All libraries

The HTTP client that made Python's networking approachable — synchronous, readable, everywhere.

A deliberately small web framework — routing and request handling, and you choose everything else.

Async web framework that derives validation, serialisation and OpenAPI docs from your type hints.

The batteries-included framework — ORM, admin, auth, migrations and templates in one coherent package.

The dataframe library that made Python a serious tool for data analysis.

The n-dimensional array that nearly every scientific Python library is built on.

SciPy is an open-source Python library used for scientific and technical computing. It builds on NumPy arrays and provides a wide range of algorithms for optimization, integration, interpolation, eigenvalue problems, algebraic equations, differential equations, and signal processing.

The foundational Python plotting library — verbose, and capable of almost any figure.

Seaborn is a Python data visualization library based on Matplotlib that provides a high-level interface for drawing attractive and informative statistical graphics.

Classical machine learning with one consistent fit/predict interface across every algorithm.

Google's end-to-end machine learning platform, strongest at production deployment.

The deep learning framework that won research, and increasingly production too.

Keras is a high-level neural networks API, written in Python and capable of running on top of TensorFlow, Microsoft Cognitive Toolkit (CNTK), or Theano. It allows for easy and fast prototyping of deep learning models with minimal code.

OpenCV-Python is a Python wrapper for the OpenCV C++ library, providing tools for computer vision, image processing, and video analysis. It allows rapid prototyping and deployment of vision applications in Python.

Forgiving HTML parser for pulling data out of pages that were never meant to be parsed.

A full crawling framework — scheduling, concurrency, retries, pipelines and throttling included.

Python's definitive database toolkit — a query builder and an ORM, usable separately.

Validation and settings management driven by type hints — the boundary guard for Python data.

Distributed task queue for work that should not happen inside a web request.

Pillow is a modern fork of the Python Imaging Library (PIL) that adds support for opening, manipulating, and saving many different image file formats in Python.

PyPDF is a pure Python library for working with PDF documents. It allows you to read, write, merge, split, and manipulate PDF files programmatically.

tox is a Python tool for automated testing in multiple environments. It allows developers to run tests across different Python versions and dependency configurations, ensuring compatibility and reliability.

Click is a Python package for creating command-line interfaces (CLI) with composable commands, automatic help page generation, and support for environment variables and configuration files.

Command-line interfaces generated from type-hinted function signatures.

Terminal output that does not look like 1985 — tables, progress bars, syntax highlighting, markdown.

Dependency management, virtual environments and publishing behind one command.

Jupyter is an open-source project that provides interactive notebooks for creating and sharing documents that contain live code, equations, visualizations, and narrative text.

NetworkX is a Python library for the creation, manipulation, and study of complex networks of nodes and edges. It provides tools to analyze the structure and dynamics of graphs and networks.

aiohttp is an asynchronous HTTP client/server framework for Python, built on top of asyncio for high-performance networking.

A Requests-compatible HTTP client that also speaks async and HTTP/2.

Sanic is a Python 3.7+ web server and web framework that’s designed for fast HTTP responses using asynchronous capabilities powered by `asyncio`. It is ideal for building high-performance APIs and web applications.

Starlette is a lightweight ASGI framework/toolkit for building high-performance asynchronous web services in Python. It provides routing, middleware, sessions, background tasks, WebSockets, and testing utilities.

Dask is a flexible library for parallel computing in Python. It allows you to scale NumPy, Pandas, and Python functions to multi-core machines or distributed clusters for large-scale data processing.

Vaex is a high-performance Python library for out-of-core DataFrames, enabling visualization and exploration of datasets larger than memory. It allows fast filtering, grouping, aggregations, and statistical computations without loading the full dataset into RAM.

Statsmodels is a Python library that provides classes and functions for the estimation of many different statistical models, as well as for conducting statistical tests and statistical data exploration.

Openpyxl is a Python library to read, write, and modify Excel 2010 xlsx/xlsm/xltx/xltm files. It allows you to create spreadsheets, read data, and perform operations on Excel files programmatically.

xlrd and xlwt are Python libraries used for reading (xlrd) and writing (xlwt) Excel files in the old .xls format. They provide tools to extract, manipulate, and create Excel spreadsheets programmatically.

PyArrow is a cross-language development platform for in-memory data, primarily designed for columnar data processing. It provides a Python interface for the Apache Arrow columnar memory format and enables efficient data interchange and analytics.

Bokeh is an interactive visualization library for Python that targets modern web browsers for presentation. It allows the creation of interactive plots, dashboards, and data applications with high-performance interactivity over large datasets.

Plotly is a Python graphing library that makes interactive, publication-quality graphs online. It supports a wide variety of chart types, including line plots, scatter plots, bar charts, 3D plots, maps, and dashboards.

Altair is a declarative statistical visualization library for Python. It allows users to create interactive and concise charts based on the Vega and Vega-Lite visualization grammars.

plotnine is a Python data visualization library based on the Grammar of Graphics, similar to ggplot2 in R. It allows building complex plots by layering components such as data, aesthetics, and geometric objects.

XGBoost (Extreme Gradient Boosting) is a high-performance, scalable, and flexible library for gradient boosting. It is widely used for supervised learning tasks such as regression, classification, and ranking.

LightGBM is a fast, distributed, high-performance gradient boosting framework based on decision tree algorithms. It is designed for efficiency and scalability, supporting large datasets and GPU acceleration.

CatBoost is a high-performance gradient boosting library from Yandex that handles categorical features automatically and efficiently. It is designed for classification, regression, and ranking tasks with minimal preprocessing.

Transformers is a Python library developed by Hugging Face that provides state-of-the-art pre-trained models for Natural Language Processing (NLP) tasks such as text classification, translation, summarization, question answering, and more.

OpenAI Gym is a toolkit for developing and comparing reinforcement learning (RL) algorithms. It provides a wide variety of environments, from classic control problems and Atari games to robotics simulations, to test and benchmark RL agents.

FastAI is a high-level deep learning library built on top of PyTorch, designed to make training neural networks fast, accurate, and accessible. It provides abstractions and best practices for vision, text, tabular, and collaborative filtering tasks.

scikit-image is a Python library for image processing that provides a collection of algorithms for segmentation, geometric transformations, color space manipulation, filtering, morphology, feature detection, and more.

ImageIO is a Python library that provides an easy interface to read and write images in a wide range of formats, including PNG, JPEG, BMP, GIF, TIFF, and more. It also supports reading and writing video files and volumetric data.

dlib is a modern C++ toolkit with Python bindings for machine learning and computer vision tasks. It includes algorithms for image processing, object detection, facial landmark detection, and general-purpose machine learning.

Loguru is a Python library that simplifies logging by providing an easy-to-use, flexible, and powerful logging system. It reduces boilerplate code and adds features like sink management, message formatting, and exception catching.

Python Fire is a library for automatically generating command-line interfaces (CLIs) from any Python object, such as functions, classes, or dictionaries. It enables rapid CLI creation without boilerplate code.

Invoke is a Python task execution library that provides a clean, high-level API for defining and running shell-oriented tasks from Python scripts. It is designed to help automate repetitive workflows, build processes, and command-line operations.

PyInquirer is a Python library that enables the creation of beautiful, interactive command-line interfaces with prompts, lists, checkboxes, and other input types inspired by Inquirer.js.

Mechanize is a Python library for stateful programmatic web browsing. It allows you to automate interaction with websites, including filling forms, clicking links, and handling cookies and sessions, similar to a web browser.

Playwright-Python is a Python library for automating web browsers. It enables end-to-end testing, web scraping, and browser automation across Chromium, Firefox, and WebKit with a single API.

The original browser automation tool — drives a real browser through the WebDriver protocol.

Requests-HTML is a Python library that combines the simplicity of the Requests library with powerful HTML parsing, web scraping, and asynchronous capabilities. It allows developers to easily fetch, parse, and manipulate HTML content.

Tortoise-ORM is an easy-to-use, asyncio-supporting Object-Relational Mapper (ORM) for Python, designed to provide a simple, familiar interface similar to Django ORM but fully asynchronous.

Peewee is a small, expressive ORM (Object-Relational Mapping) library for Python. It provides a simple and lightweight way to interact with databases using Pythonic models and queries, supporting SQLite, MySQL, and PostgreSQL.

MongoEngine is an Object-Document Mapper (ODM) for Python that provides a high-level abstraction for working with MongoDB. It allows developers to define schemas and interact with MongoDB documents using Python classes instead of raw queries.

Paramiko is a Python library for SSH2 protocol, providing both client and server functionality. It allows you to securely connect to remote machines, execute commands, transfer files over SFTP, and manage SSH sessions programmatically.

Asyncio is Python's standard library for writing concurrent code using the async/await syntax. It provides an event loop, coroutines, tasks, and futures to facilitate asynchronous programming and I/O-bound operations.

Twisted is an event-driven networking engine written in Python. It provides a robust framework for building asynchronous networked applications, including servers, clients, and protocols for TCP, UDP, SSL/TLS, and more.

Pathlib is a Python standard library module that provides an object-oriented interface for working with filesystem paths. It simplifies file and directory manipulations across different operating systems.

Pendulum is a Python library for handling dates, times, and time zones. It provides a cleaner and more intuitive API than the standard `datetime` module, with precise parsing, formatting, and manipulation of date and time objects.

Arrow is a Python library that provides a sensible, human-friendly approach to creating, manipulating, formatting, and converting dates and times. It simplifies working with time zones and datetime arithmetic.

PyYAML is a Python library for parsing and writing YAML (YAML Ain’t Markup Language) files. It allows you to read YAML data into Python objects and serialize Python objects back into YAML format.

JSONSchema is a Python library for validating JSON data against a schema. It allows developers to ensure that JSON objects conform to a defined structure, including types, required properties, and value constraints.

SNScrape is a Python library for scraping social networking services such as Twitter, Facebook, Reddit, and more. It allows fetching posts, comments, tweets, user profiles, and other social data without using official APIs.

Social Post API is a Python library for interacting with various social media platforms to post updates, retrieve feeds, and manage user content programmatically. It provides a unified interface to handle multiple platforms like Twitter, Facebook, LinkedIn, and Instagram.

Tweepy is a Python library for accessing the Twitter API easily. It provides a convenient interface to retrieve tweets, post updates, manage followers, and interact with Twitter data programmatically.

python-twitter is a Python wrapper around the Twitter API, providing a simple interface to access Twitter data, post tweets, and manage accounts programmatically.

Instaloader is a Python library to download Instagram photos, videos, stories, IGTV, and profiles. It allows you to scrape Instagram content programmatically for personal or research purposes.

Instagrapi is a modern Python library for Instagram automation. It allows you to programmatically interact with Instagram, including posting photos and stories, managing followers, reading feeds, and downloading media.

The Facebook SDK for Python is a library that allows developers to interact with the Facebook Graph API. It provides tools for posting content, retrieving user data, managing pages, and working with Facebook Ads programmatically.

PyFacebook is a Python SDK for interacting with the Facebook Graph API. It allows developers to manage Facebook pages, post content, retrieve insights, and handle user and page data programmatically.

python-telegram-bot is a Python library that provides a pure Python interface for the Telegram Bot API. It allows developers to build bots to interact with Telegram users, send messages, handle commands, and integrate with other services.

Telethon is a Python library to interact with Telegram’s API as a user or bot. It allows you to send messages, manage groups, channels, and perform a wide range of Telegram actions programmatically.

Aiogram is a modern and fully asynchronous Python framework for building Telegram bots. It leverages Python’s asyncio capabilities to provide high-performance, scalable, and efficient bot development.

discord.py is a Python library for interacting with the Discord API. It allows developers to create bots that can interact with Discord servers, send and receive messages, manage roles, and respond to events programmatically.

Pycord is a Python library for building Discord bots, providing an easy-to-use interface for interacting with Discord’s API. It allows developers to handle events, send messages, create commands, manage servers, and automate workflows within Discord.

Hikari is a modern, fast, and type-safe Python library for building Discord bots. It is designed for high performance, asynchronous execution, and full support of Discord API features.

The default way to build a Java service — auto-configuration over a vast, mature ecosystem.

Spring Security is a powerful and highly customizable framework for authentication, authorization, and protection against common security threats in Java applications.

The JPA implementation that defined ORM on the JVM.

The JSON library the JVM ecosystem standardised on.

Gson is a Java library by Google for converting Java objects to JSON and vice versa. It supports serialization and deserialization of Java objects, including collections, generics, and nested objects.

The HTTP client behind most JVM and Android networking, including Retrofit's.

Retrofit is a type-safe HTTP client for Java and Android, developed by Square. It allows you to define REST API endpoints as Java interfaces and automatically converts HTTP responses into Java objects using converters like Gson or Jackson.

Feign is a declarative HTTP client for Java, primarily used with Spring Cloud to simplify REST API calls. It allows developers to define API clients using interfaces and annotations.

MapStruct is a Java annotation processor for generating type-safe and performant mappers that automatically convert between Java beans (DTOs and entities).

Annotations that generate boilerplate — getters, builders, constructors — at compile time.

SLF4J (Simple Logging Facade for Java) is a logging abstraction that allows developers to plug in various logging frameworks such as Logback, Log4j, or java.util.logging without changing application code.

High-performance logging with async appenders and structured output.

The JVM's standard testing framework, rebuilt around an extension model.

Mocking for unit tests, with an API that stays readable.

AssertJ is a fluent and rich assertion library for Java that allows developers to write readable and expressive unit test assertions. It provides a wide variety of assertions for core Java types, collections, exceptions, and more.

Real databases, brokers and services in Docker containers, started by your tests.

Vert.x is a toolkit for building reactive, non-blocking, and polyglot applications on the JVM. It supports asynchronous programming, event-driven architecture, and high-performance microservices.

Micronaut is a modern, JVM-based framework for building modular, easily testable microservices and serverless applications. It emphasizes low memory footprint, fast startup time, and dependency injection with compile-time optimizations.

A Java stack built for containers — fast startup, low memory, first-class native compilation.

Distributed event log for streaming data between systems at scale.

Asynchronous network application framework — the engine under a great deal of JVM infrastructure.

Jersey is the reference implementation of JAX-RS (Java API for RESTful Web Services) for building RESTful web services in Java. It simplifies creating web services with annotations, dependency injection, and automatic JSON/XML support.

RestEasy is a JAX-RS implementation for building RESTful web services in Java. It provides tools to create REST APIs easily with annotations, dependency injection, exception handling, and integrates well with JBoss/WildFly or standalone servlet containers.

Apache CXF is a framework for building robust web services in Java. It supports both RESTful (JAX-RS) and SOAP-based (JAX-WS) services, providing tools for service creation, client generation, and integration with various transports and data bindings.

MyBatis is a persistence framework that simplifies working with relational databases in Java. Unlike full ORM frameworks, it focuses on mapping SQL queries to Java objects, giving developers control over SQL while reducing boilerplate code.

jOOQ (Java Object Oriented Querying) is a fluent API for typesafe SQL query construction in Java. It allows developers to write SQL in a natural, type-checked way while mapping results directly to Java objects, combining the flexibility of SQL with the safety of Java.

Google's core Java libraries — collections, caching, primitives and utilities.

Apache Commons Lang provides a host of helper utilities for the java.lang API, making everyday Java development easier. It includes functionality for String manipulation, object reflection, concurrency, number handling, date/time, and more.

Apache Commons IO provides utilities for working with Java I/O, including file and directory manipulation, file filters, input/output stream handling, and file monitoring. It simplifies common I/O operations and reduces boilerplate code.

Apache Commons Collections extends the Java Collections Framework with additional interfaces, implementations, and utilities for manipulating and transforming collections. It includes features like Bag, MultiMap, BidiMap, and advanced iterators.

Apache Commons Configuration provides a unified API for accessing configuration data from various sources, including properties files, XML, INI, JSON, and databases. It supports hierarchical configurations, automatic reloading, and combined configuration sources.

Google Guice is a lightweight dependency injection framework for Java. It allows you to manage object creation and dependencies declaratively using annotations, reducing boilerplate and promoting loose coupling.

Apache HttpClient is a robust and feature-rich HTTP client library for Java. It allows sending HTTP requests, handling responses, managing connections, cookies, authentication, and supporting advanced features like redirects and timeouts.

Jakarta Mail (formerly JavaMail) is a Java API for sending, receiving, and managing email messages using protocols such as SMTP, IMAP, and POP3. It provides a simple interface for building email applications and integrating email functionality into Java applications.

Flyway is an open-source database migration tool for Java that allows developers to version, manage, and automate database schema changes. It supports SQL-based migrations as well as Java-based migrations for complex transformations.

RxJava is a Java library for composing asynchronous and event-based programs using observable sequences. It provides powerful operators for managing concurrency, data streams, and transformations in a functional style.

Project Reactor is a reactive library for building non-blocking, asynchronous, and event-driven applications on the JVM. It provides types like Mono and Flux to handle zero-to-one and zero-to-many reactive sequences respectively, following the Reactive Streams specification.

RabbitMQ Java Client is a Java library for interacting with RabbitMQ, a message broker that implements the Advanced Message Queuing Protocol (AMQP). It enables applications to send, receive, and process messages asynchronously and reliably.

Apache ActiveMQ is a popular open-source message broker that implements JMS (Java Message Service). The ActiveMQ Java Client library allows Java applications to send, receive, and process messages asynchronously and reliably across distributed systems.

Redisson is a Java client for Redis that provides a high-level, distributed Java data structures framework. It allows Java applications to interact with Redis using objects, collections, locks, atomic variables, and other advanced features in a thread-safe and cluster-aware manner.

Arquillian is a powerful testing platform for Java that simplifies integration and functional testing of Java EE and Jakarta EE applications. It allows developers to execute tests inside real runtime containers rather than mocks, ensuring realistic behavior and deployment conditions.

WireMock is a flexible and powerful Java library for mocking HTTP services. It allows developers to stub, simulate, and test interactions with external APIs, enabling reliable and isolated testing of client code without depending on real external services.

Awaitility is a Java DSL (Domain Specific Language) for testing asynchronous code. It allows developers to wait for a certain condition to be met within a specified time period, making testing of async operations, background tasks, or event-driven systems more reliable and readable.

Apache Maven is a powerful build automation and project management tool for Java and other JVM-based languages. It provides a uniform build system, dependency management, and a project object model (POM) to define project structure, plugins, and external libraries.

Gradle is a modern build automation tool for Java, Kotlin, and other JVM-based languages. It provides a flexible, high-performance build system with support for dependency management, multi-project builds, and incremental compilation, making it ideal for complex enterprise projects.

Apache Shiro is a powerful and easy-to-use Java security framework that performs authentication, authorization, cryptography, and session management. It simplifies securing applications by providing a flexible and intuitive API.

Java JWT libraries provide tools for creating, parsing, and validating JSON Web Tokens (JWT) in Java applications. They are widely used for implementing stateless authentication, secure token-based authorization, and claims-based identity management.

FastUtil is a Java library that provides fast and memory-efficient collections for primitive types, including maps, sets, lists, and more. It offers specialized implementations that avoid the overhead of boxing/unboxing primitive types, improving performance in high-throughput applications.

Logback is a popular Java logging framework intended as a successor to Log4j. It provides powerful configuration options, fast performance, and a rich set of appenders and layouts for logging messages in various formats and destinations.

Micrometer is a metrics instrumentation library for Java applications that provides a vendor-neutral interface for capturing application metrics and exposing them to monitoring systems. It supports counters, gauges, timers, distribution summaries, and more.

Protocol Buffers (Protobuf) is a language-neutral, platform-neutral, and extensible mechanism for serializing structured data. It is used to efficiently encode data for communication between services, storage, or configuration in Java applications.

Apache Avro is a data serialization system that provides compact, fast, and binary data serialization for Java and other languages. It is widely used in big data ecosystems for storing and transmitting structured data efficiently.

Jetty is a lightweight, high-performance Java HTTP server and servlet container. It provides an embedded web server, making it easy to integrate into Java applications for serving web content, REST APIs, or acting as a backend server.

Apache HttpComponents is a set of Java libraries for client-side and server-side HTTP communication. The most commonly used module is HttpClient, which provides a robust and flexible API for sending HTTP requests and handling responses.

Spring Cloud provides a suite of tools for building distributed systems and microservices in Java. It integrates with Spring Boot to offer service discovery, configuration management, load balancing, circuit breakers, messaging, and cloud-native patterns.

Consul and Eureka are popular service discovery tools for microservices. Java clients integrate applications with these services, enabling automatic registration, service lookup, and health monitoring for distributed systems.

Apache POI is a Java library for reading and writing Microsoft Office file formats, including Excel, Word, and PowerPoint. It enables Java applications to manipulate spreadsheets, documents, and presentations programmatically.

iText and Apache PDFBox are Java libraries for creating, manipulating, and reading PDF documents. They allow developers to generate dynamic PDFs, extract content, fill forms, merge or split documents, and manage metadata programmatically.

Jsoup is a Java library for working with real-world HTML. It provides a convenient API for fetching URLs, parsing HTML, extracting and manipulating data, and cleaning user-submitted content to prevent XSS attacks.

Quartz is a powerful and widely used Java library for scheduling and executing jobs. It allows developers to define tasks, schedule them with cron-like expressions or fixed intervals, and manage job execution in enterprise applications.

Ehcache and Caffeine are Java caching libraries that improve application performance by storing frequently accessed data in memory, reducing expensive database or API calls. They support in-memory and optionally persistent caching with flexible eviction and expiration policies.

MapDB is an embedded Java database and caching library that provides fast, concurrent, and off-heap key-value storage. It supports maps, sets, queues, and other collections with optional persistence to disk or memory-mapped files.

Apache Ignite is a distributed in-memory data grid and caching platform for Java. It provides high-performance key-value storage, SQL querying, ACID transactions, compute grid, and integration with other data sources.

Hazelcast is a distributed in-memory data grid and caching platform for Java. It provides high-performance storage for key-value data, distributed maps, queues, topics, and support for distributed computing, clustering, and transactions.

JavaCV provides Java bindings for OpenCV and other computer vision libraries, allowing developers to process images and videos, detect objects, and apply advanced computer vision algorithms in Java applications.

Deeplearning4j (DL4J) is an open-source, distributed deep learning library for Java and JVM-based languages. It allows building, training, and deploying neural networks for tasks like image recognition, NLP, time series analysis, and more.

ND4J (N-Dimensional Arrays for Java) is a scientific computing library for the JVM, providing high-performance n-dimensional arrays, linear algebra operations, and GPU acceleration. It serves as the foundation for Deeplearning4j and other Java-based ML frameworks.

Weka is a collection of machine learning algorithms for data mining tasks in Java. It provides tools for classification, regression, clustering, association rule mining, and data preprocessing, with both a GUI and programmatic API.

MOA is an open-source Java framework for data stream mining. It provides tools for classification, regression, clustering, and concept drift detection on high-speed streaming data.

Apache Flink is a powerful open-source framework for distributed stream and batch data processing. Flink ML provides machine learning libraries for building scalable models on streaming and batch data.

Apache Spark is an open-source distributed computing system for big data processing. Spark MLlib provides scalable machine learning algorithms for classification, regression, clustering, and collaborative filtering, usable in Java, Scala, and Python.

Apache Beam is an open-source unified programming model for defining and executing data processing pipelines, both batch and streaming. It provides Java, Python, and Go SDKs and can run on multiple runners like Flink, Spark, and Dataflow.

Apache Camel is a versatile open-source integration framework that provides routing and mediation rules for connecting different systems. It implements Enterprise Integration Patterns (EIPs) and supports hundreds of components for various protocols and data formats.

Apache NiFi is an open-source data integration and automation tool for designing, managing, and monitoring data flows. It supports real-time data ingestion, routing, transformation, and delivery between systems.

The HTTP client behind an enormous share of software — every protocol, every platform.

The cryptography and TLS library most of the internet depends on.

The DEFLATE compression library that gzip, PNG and countless formats are built on.

Xlib is the standard C library for interfacing with the X Window System (X11) on Unix-like operating systems. It allows applications to create and manage windows, handle user input events, draw graphics, and communicate with the X server.

A complete SQL database in a single file, embedded directly in your process.

libxml2 is a C library for parsing XML documents. It provides a comprehensive set of functions for reading, validating, navigating, and manipulating XML data efficiently, and supports standards like XPath, XInclude, and XPointer.

Jansson is a C library for encoding, decoding, and manipulating JSON data. It provides simple and intuitive APIs to parse JSON strings, build JSON objects, arrays, and write JSON to files or memory.

A tiny JSON parser in a single C file you can drop into any project.

Cross-platform access to graphics, audio, input and windowing for games and multimedia.

GTK (GIMP Toolkit) is a multi-platform toolkit for creating graphical user interfaces. In Python, GTK is accessible via the PyGObject library, allowing developers to build desktop applications with windows, dialogs, buttons, menus, and more.

The cross-platform async I/O library extracted from Node.js.

libpng is the official PNG reference library for C. It provides functions to read, write, and manipulate PNG (Portable Network Graphics) images, supporting compression, filtering, and color types.

libjpeg-turbo is a high-speed version of the standard JPEG image codec library, using SIMD instructions (MMX, SSE2, NEON, AltiVec) to accelerate JPEG compression and decompression.

OpenAL (Open Audio Library) is a cross-platform 3D audio API designed for efficient rendering of multichannel spatialized audio. It is used in games, simulations, and multimedia applications to provide immersive sound experiences.

Terminal user interfaces — windows, colours and keyboard handling in a text console.

Check is a unit testing framework for C that allows developers to write test cases for their code in a simple and structured way. It provides assertions, test fixtures, and test suites to ensure code correctness.

Unity is a cross-platform game engine that allows developers to create 2D, 3D, VR, and AR games. While Unity primarily uses C#, low-level plugins and performance-critical components can be developed using C or C++ for integration via Unity's Native Plugin Interface.

Poppler is a PDF rendering library based on the xpdf-3.0 code base. It provides tools and APIs to extract text, render pages, and manipulate PDF files in C and C++ applications.

MuPDF is a lightweight, high-performance PDF, XPS, and EPUB rendering library written in C. It allows text extraction, page rendering, and manipulation of PDF documents with minimal memory usage.

CMocka is a lightweight, modern unit testing framework for C. It provides a simple API for writing unit tests, mocking functions, and verifying behavior in C programs.

pthread (POSIX Threads) is a standard C library for creating and managing threads. It provides APIs for multithreading, synchronization, and concurrency control in C programs on POSIX-compliant systems.

Cairo is a 2D graphics library that supports vector graphics, including drawing shapes, text, and images. It provides high-quality rendering for multiple output targets such as screens, PDFs, SVGs, and image buffers.

FreeType is a C library for rendering fonts, supporting various font formats such as TrueType, OpenType, Type1, and CFF. It provides functionality to load, rasterize, and render glyphs for text display in applications.

LevelDB is a fast, lightweight, single-purpose key-value storage library written in C++. It provides ordered mapping from string keys to string values with support for batch writes, snapshots, and iterators.

bzip2 is a high-quality data compression library and tool that uses the Burrows-Wheeler algorithm and Huffman coding. It provides better compression ratios than traditional gzip for many types of files.

LZ4 is an extremely fast lossless compression algorithm and library. It focuses on compression and decompression speed while maintaining reasonable compression ratios, making it ideal for real-time applications and large data streams.

libwebsockets is a lightweight C library for building WebSocket servers, clients, and HTTP(S) servers. It supports asynchronous, event-driven communication over WebSocket and HTTP protocols.

libevent is a high-performance C library that provides asynchronous event notification. It allows applications to execute callbacks when file descriptors, signals, or timers become active, enabling scalable network servers and event-driven programs.

libev is a high-performance event loop library in C that provides asynchronous I/O, timers, signals, and child process handling. It is designed for efficiency and scalability in networked and event-driven applications.

GLFW is an open-source library for creating windows, contexts, and handling input and events in OpenGL, OpenGL ES, and Vulkan applications. It is designed to be simple, portable, and lightweight, ideal for graphics and game development.

A vast collection of peer-reviewed C++ libraries, many of which became the standard library.

The most complete cross-platform C++ application framework — GUI and much else.

POCO (Portable Components) is a set of modern C++ libraries that provide building blocks for network-centric, portable applications. It includes modules for networking, HTTP, XML, JSON, threading, file system access, and more.

JSON that behaves like a native C++ type — intuitive, header-only, widely adopted.

Fast, safe, Python-style string formatting — the basis of C++20's `std::format`.

Very fast C++ logging, header-only, with synchronous and asynchronous modes.

Header-only C++ testing with expressive assertions and no external dependencies.

Google's C++ testing framework, paired with GoogleMock for mocking.

Google's binary serialisation format with schema-driven code generation.

The computer vision library — image processing, detection, tracking and calibration.

Header-only linear algebra with expression templates that eliminate temporaries.

Cereal is a C++11 library for serialization of data structures. It allows converting C++ objects to JSON, XML, or binary formats, and deserializing them back into objects efficiently and safely.

cxxopts is a lightweight C++ library for parsing command-line options. It provides a simple and modern API to define options, parse arguments, and handle help messages, making it ideal for CLI applications.

Range-v3 is a C++ library that extends the standard library with a powerful range-based API. It provides composable, lazy-evaluated views and actions on sequences, enabling expressive and functional-style operations on containers and iterators.

SFML (Simple and Fast Multimedia Library) is a multimedia library written in C++ that provides simple APIs for graphics, window management, audio, and networking. It is designed to be user-friendly and portable, ideal for 2D games and multimedia applications.

Assimp (Open Asset Import Library) is a portable and extensible library that imports and processes 3D models in various formats. It provides a unified API for loading meshes, materials, animations, and scene data from files like OBJ, FBX, COLLADA, and many more.

Bullet Physics is a professional-grade physics simulation library for real-time collision detection, rigid body dynamics, soft body dynamics, and vehicle simulation. It is widely used in games, VR, robotics, and film production.

OGRE (Object-Oriented Graphics Rendering Engine) is a scene-oriented, flexible 3D rendering engine written in C++. It abstracts low-level graphics APIs like OpenGL and Direct3D, providing a high-level interface for rendering 3D graphics in applications such as games, simulations, and visualizations.

Magnum is a lightweight and modular C++11/C++14 graphics middleware for 2D and 3D graphics, game development, and visualization. It builds on top of modern OpenGL, Vulkan, and WebGPU APIs, offering a clean, extensible framework for rendering, math, input, and asset management.

Armadillo is a high-quality C++ linear algebra library that provides efficient matrix and vector operations, while offering a syntax similar to MATLAB. It is designed for both speed and ease of use, making it popular in scientific computing, machine learning, and signal processing.

MLPack is a fast, flexible, and scalable C++ machine learning library. It provides a wide range of machine learning algorithms and data science tools with a focus on high performance and ease of use, while also offering bindings for Python, Julia, and other languages.

Caffe is a deep learning framework made with expression, speed, and modularity in mind. Written in C++, it provides a clean architecture for defining, training, and deploying deep neural networks, with bindings for Python and MATLAB.

SOCI is a C++ database access library that provides a clean, type-safe, and object-oriented abstraction over SQL databases. It acts like a lightweight ORM but retains full SQL control, offering both simplicity and flexibility.

RocksDB is an embeddable, high-performance, persistent key-value store developed by Facebook. It is based on LevelDB but optimized for fast storage, low-latency access, and high throughput on flash drives and SSDs.

LMDB (Lightning Memory-Mapped Database) is a high-performance, memory-mapped key-value store developed by the OpenLDAP project. It is compact, transactional, and highly efficient, designed for read-heavy workloads with low latency.

Cap’n Proto is a fast data interchange format and RPC system. It provides schema-based serialization similar to Protocol Buffers, but with zero-copy design, enabling extremely fast message passing and storage.

FlatBuffers is a highly efficient cross-platform serialization library developed by Google. It allows direct access to serialized data without parsing/unpacking, making it ideal for games, mobile apps, and high-performance applications.

Brokerless messaging patterns — sockets that speak pub/sub, request/reply and push/pull.

High-performance RPC over HTTP/2, with generated clients and servers from a schema.

uWebSockets is a highly efficient C++ WebSocket and HTTP library designed for scalability and minimal resource usage. It supports millions of concurrent connections and powers some of the largest real-time applications, including trading platforms and messaging systems.

Intel oneTBB (Threading Building Blocks) is a C++ template library that simplifies parallel programming by providing high-level abstractions for tasks, parallel loops, pipelines, and concurrent data structures. It enables developers to harness multicore processors efficiently without directly managing threads.

OpenMP (Open Multi-Processing) is an API that supports multi-platform shared-memory multiprocessing programming in C, C++, and Fortran. It provides a set of compiler directives, runtime library routines, and environment variables for parallelizing code easily on multi-core CPUs.

HPX (High Performance ParalleX) is a C++ runtime system for parallel and distributed applications. It provides a standards-conforming API for asynchronous task-based programming, scalability across many cores, and distributed computing with an emphasis on performance portability.

The Guidelines Support Library (GSL) is a set of C++ utilities developed to help programmers follow the C++ Core Guidelines. It provides types and functions such as span, not_null, owner, and utilities for safer memory and pointer usage.

EnTT is a fast and flexible C++ Entity-Component-System (ECS) library used in game development and simulation. It provides efficient memory management, entity lifecycle handling, component storage, and iteration utilities for building scalable and data-driven applications.

CLI11 is a C++11 header-only library for parsing command line arguments. It provides an expressive, modern C++ API for handling flags, options, subcommands, and configuration files with minimal boilerplate.

loctest is a lightweight and minimal C++ testing framework designed to provide simple and readable unit tests. It focuses on clarity and small binary size, making it a good choice for embedded systems and projects that don’t require heavy testing infrastructure.

Trompeloeil is a modern C++14 mocking framework for unit testing. It provides a type-safe, expressive API for creating mocks, setting expectations, and verifying interactions between objects.

glog is Google’s C++ logging library that provides application-level logging with different severity levels (INFO, WARNING, ERROR, FATAL). It is designed for robustness, simplicity, and performance, making it suitable for large-scale systems.

plog is a portable, simple, and extensible C++ logging library. It supports multiple logging destinations, severity levels, thread safety, and works across platforms with minimal dependencies.

A comprehensive React component library implementing Material Design.

Ant Design is a React UI library with a set of high-quality components and design guidelines for building rich, enterprise-level web applications. It emphasizes consistency, usability, and customization.

Chakra UI is a simple, modular, and accessible component library for React applications. It provides composable components with built-in theming, responsive styles, and accessibility support by default.

Headless UI is a set of completely unstyled, accessible UI components for React and Vue. It provides the functionality and accessibility features, leaving styling fully up to you.

Unstyled, accessible component primitives — behaviour without opinions about appearance.

Not a dependency — components you copy into your project and own outright.

Mantine is a modern React component library that provides over 100 fully featured components and hooks. It supports server-side rendering, dark theme, accessibility, and offers an extensive set of form and data display components.

Evergreen is a React UI framework developed by Segment. It provides a set of polished, flexible, and accessible components designed for enterprise-grade web applications.

React Bootstrap is a popular UI framework that rebuilds Bootstrap components entirely with React. It removes jQuery dependencies while keeping the same look and feel of traditional Bootstrap.

NextUI is a modern React UI library built with accessibility, dark mode, and theming support out of the box. It offers a sleek design system with customizable and easy-to-use components.

Aceternity UI is a modern component collection built with Next.js, React, Tailwind CSS, and Framer Motion. It offers stunning animated effects and copy-and-paste components (no npm package required), perfect for visually engaging UI buildouts.

Tailwind UI is a premium set of professionally designed, fully responsive UI components built with Tailwind CSS. It includes application UI, marketing UI, and e-commerce components ready to use in React, Vue, and plain HTML.

HyperUI is a free collection of open-source Tailwind CSS components. It provides a wide range of copy-and-paste components such as cards, modals, forms, navigation, and more.

UIverse is a free collection of open-source, copy-paste UI components built with CSS, Tailwind CSS, and React. It provides a wide range of modern components, including buttons, loaders, cards, inputs, and more.

Angular Material is the official UI component library for Angular, built with Google's Material Design system. It provides a wide range of reusable, accessible, and customizable UI components.

NG-ZORRO is an Angular UI component library based on Ant Design. It provides a wide range of high-quality, accessible, and enterprise-ready UI components specifically for Angular applications.

PrimeNG is a comprehensive UI component library for Angular, offering a wide range of rich and responsive components including forms, data tables, charts, menus, and more, following modern design patterns.

Vuetify is a Material Design component framework for Vue.js, providing a comprehensive suite of reusable, accessible, and responsive UI components.

Element Plus is a Vue 3 UI component library that provides a rich set of high-quality, reusable components for building modern web applications with a clean design aesthetic.

Naive UI is a Vue 3 component library that offers a complete, customizable, and TypeScript-friendly set of components for building modern web applications.

Quasar is a Vue.js framework that allows developers to build responsive websites, mobile apps (with Cordova or Capacitor), and Electron desktop apps using a single codebase. It provides a rich set of UI components, utilities, and build tools.

PrimeVue is a rich set of open-source UI components for Vue.js applications. It provides a variety of ready-to-use components like buttons, tables, charts, forms, dialogs, and more with modern design and accessibility support.

Utility classes that keep styling in the markup and the CSS bundle small.

Flowbite is a component library built on top of Tailwind CSS that provides ready-to-use interactive UI components such as buttons, modals, dropdowns, and navigation menus.

DaisyUI is a plugin for Tailwind CSS that provides a set of accessible, responsive, and themeable UI components. It extends Tailwind with ready-made components like buttons, forms, cards, modals, and more.

Lucide is a simple, consistent, and customizable icon library for web projects. It offers a wide range of open-source, SVG-based icons that are lightweight and easy to integrate.

Heroicons is a set of free, MIT-licensed high-quality SVG icons for UI development. It provides both outline and solid styles, optimized for modern web applications.

Phosphor is a flexible and versatile icon library for web and mobile projects. It offers a wide range of customizable icons in multiple weights, styles, and formats, suitable for React, Vue, or plain HTML usage.

Tailblocks is a collection of ready-to-use Tailwind CSS blocks for building websites quickly. It provides pre-designed sections like headers, footers, pricing, features, testimonials, and more.

TailwindComponents is a community-driven library of free and open-source Tailwind CSS components and templates. It provides ready-to-use UI elements like buttons, cards, navigation bars, forms, and full-page templates.

Predictable state container with a strict unidirectional data flow and time-travel debugging.

A small, hook-based store with almost no ceremony.

Recoil is a state management library for React that provides a simple and flexible way to share state across components. It allows for fine-grained state updates, derived state, and asynchronous selectors while integrating seamlessly with React's concurrent features.

MobX is a simple, scalable, and battle-tested state management library for JavaScript applications. It allows you to manage application state outside of components while keeping your UI automatically in sync with state changes.

Jotai is a primitive and flexible state management library for React. It provides atoms as units of state, allowing fine-grained control over state updates without the boilerplate of larger libraries like Redux.

The routing standard for React single-page applications.

Vue Router is the official router for Vue.js, enabling navigation between components and views in a Vue application. It provides declarative routing, nested routes, dynamic route matching, and navigation guards.

Form state built on uncontrolled inputs, so typing does not re-render the whole form.

Formik is a popular React library for building and managing forms with ease. It simplifies form state management, validation, and submission handling while reducing boilerplate code.

VeeValidate is a form validation library for Vue.js that allows you to validate forms and inputs declaratively. It provides built-in validation rules, custom rules, and integrates seamlessly with Vue's reactivity system.

Declarative animation for React — layout transitions, gestures and exit animations.

The professional animation engine — precise timelines, scroll triggers, framework-agnostic.

Anime.js is a lightweight JavaScript animation library that works with CSS properties, SVG, DOM attributes, and JavaScript objects. It enables creating smooth, powerful, and complex animations with a simple API.

Promise-based HTTP client with interceptors and automatic JSON handling.

Lightweight data fetching with stale-while-revalidate caching.

Server state management — caching, revalidation, retries and background updates for data you fetch.

The utility belt that predates most of what JavaScript later added natively.

Modular date utilities — import only the functions you use, no wrapper object.

The original JavaScript date library — now officially in maintenance mode.

A 2 KB Moment.js replacement with a nearly identical API.

Ramda is a practical functional library for JavaScript programmers. It provides a suite of utility functions for functional programming, emphasizing immutability, currying, and composition.

The long-standing JavaScript test runner, with mocking and snapshots included.

A fast, Vite-native test runner with a Jest-compatible API.

End-to-end testing with a live, interactive test runner in the browser.

End-to-end browser testing with auto-waiting, across Chromium, Firefox and WebKit.

The build tool that made front-end development feel instant.

The bundler that defined a decade of front-end tooling — endlessly configurable.

Rollup is a JavaScript module bundler that compiles small pieces of code into something larger and more complex, such as a library or application. It uses ES modules to produce optimized, tree-shaken bundles.

Parcel is a fast, zero-configuration web application bundler. It supports JavaScript, TypeScript, CSS, HTML, images, and more out of the box without requiring a complex configuration.

Gin is a high-performance HTTP web framework for Go with a martini-like API. It provides routing, middleware, JSON binding and validation on top of net/http, and is one of the most widely used Go web frameworks.

Echo is a minimalist, high-performance Go web framework with a strong middleware system, automatic TLS via Let's Encrypt, and first-class data binding and validation. It emphasises an explicit, well-typed handler signature.

Fiber is a Go web framework built on fasthttp rather than net/http, with an API deliberately modelled on Express.js. It targets maximum raw throughput and low memory allocation.

chi is a lightweight, idiomatic HTTP router for Go that is fully compatible with net/http. Handlers are plain http.HandlerFunc, so any standard-library middleware works without adaptation.

gorilla/mux is a powerful URL router and dispatcher for Go, supporting matching on host, path, headers, query values and HTTP methods. It is part of the long-established Gorilla web toolkit.

Resty is a simple, chainable HTTP and REST client for Go, adding retries, middleware, automatic marshalling and response parsing on top of net/http.

GORM is the most widely used ORM for Go, offering associations, hooks, migrations, transactions and eager loading over a struct-based model definition.

sqlx is a thin set of extensions over Go's database/sql that adds struct scanning, named parameters and helpers, without becoming an ORM.

pgx is a PostgreSQL driver and toolkit for Go that bypasses database/sql to expose PostgreSQL-specific features and significantly better performance.

sqlc generates fully type-safe Go code from your SQL queries. You write .sql files; it produces Go functions with typed parameters and return structs.

go-redis is the most widely used Redis client for Go, supporting cluster mode, sentinel, pipelining, pub/sub and streams with a context-aware API.

Cobra is the CLI framework behind kubectl, Hugo, GitHub CLI and Docker, providing nested subcommands, flag parsing, help generation and shell completion.

Viper is a configuration library that merges defaults, config files, environment variables, flags and remote key stores into one lookup, with live reloading.

Zap is Uber's structured logging library for Go, designed for very low allocation overhead in hot paths while producing machine-readable JSON.

zerolog is a zero-allocation JSON logger for Go with a chainable API, aimed at the same performance goals as Zap with a lighter interface.

Testify adds assertions, mocks and test suites on top of Go's standard testing package, and is the most widely used Go testing library.

The official Go implementation of gRPC — typed RPC over HTTP/2 with generated clients and servers, streaming in both directions, deadlines and interceptors.

The Go implementation of Protocol Buffers — compact binary serialisation with a schema, generated types and forward and backward compatibility.

Sarama is a pure-Go client for Apache Kafka, supporting producers, consumer groups, offset management and the admin API with no cgo dependency.

The Go client for NATS, a lightweight messaging system supporting publish/subscribe, request/reply and queue groups, with optional persistence via JetStream.

go-playground/validator performs struct validation from field tags, covering required fields, ranges, formats, cross-field rules and custom validators.

golang-jwt is the maintained community fork of dgrijalva/jwt-go, providing JSON Web Token signing, parsing and validation.

Colly is a fast web scraping framework for Go with callback-based parsing, automatic rate limiting, caching, cookie handling and parallel collectors.

GJSON reads values from JSON with a dot-notation path syntax, without defining structs or unmarshalling the whole document.

A cron-expression job scheduler for Go, supporting standard cron syntax, descriptive shortcuts, time zones and second-level precision.

The official Go instrumentation library for Prometheus, providing counters, gauges, histograms and summaries plus an HTTP handler to expose them.

The Go SDK for OpenTelemetry — vendor-neutral distributed tracing, metrics and logs that can be exported to Jaeger, Tempo, Datadog or any OTLP backend.

Bubble Tea is a framework for building terminal user interfaces in Go, based on the Elm architecture of model, update and view.

Zod is a TypeScript-first schema declaration and validation library. One schema produces both the runtime check and the static type, so the two can never drift apart.

Valibot is a schema validation library with an API similar to Zod's but built around tree-shakeable functions, producing dramatically smaller client bundles.

TypeBox builds JSON Schema objects that also carry TypeScript types, so one definition serves runtime validation, static typing and OpenAPI documentation.

tRPC gives you end-to-end type safety between a TypeScript server and client with no code generation, no schema files and no build step.

Prisma is a next-generation ORM with a declarative schema, generated type-safe client, and a migration system that produces reviewable SQL.

Drizzle is a TypeScript ORM whose query builder mirrors SQL closely, with no code generation step and a very small runtime suitable for serverless and edge environments.

Kysely is a type-safe SQL query builder for TypeScript. It is not an ORM — you write SQL structure, and the types follow your database schema exactly.

NestJS is a structured Node.js framework built on TypeScript decorators, with dependency injection, modules and a strong architectural convention.

ts-pattern brings exhaustive pattern matching to TypeScript, with full type narrowing and a compile-time guarantee that every case is handled.

neverthrow provides a Result type for TypeScript, making failure part of a function's return type instead of an invisible exception.

typescript-eslint lets ESLint parse and lint TypeScript, including rules that use full type information to catch bugs a syntax-only linter cannot see.

tsx runs TypeScript files directly with no build step, using esbuild for near-instant transpilation. It is the modern replacement for ts-node.

tsup bundles TypeScript libraries with almost no configuration, producing ESM and CommonJS output plus declaration files in one command.

type-fest is a collection of essential TypeScript utility types that the standard library does not include, from deep partials to JSON value types.

class-validator validates objects using decorators on class properties, and is the validation layer built into NestJS.

tsyringe is a lightweight dependency injection container for TypeScript from Microsoft, using decorators and constructor injection.

openapi-typescript generates TypeScript types from an OpenAPI schema, giving a typed client for an API you do not control.

SuperJSON serialises JavaScript values that JSON cannot represent — Date, Map, Set, BigInt, undefined and RegExp — and restores them on the other side.

ts-morph wraps the TypeScript compiler API in a navigable, mutable object model, making programmatic code analysis and refactoring practical.

TypeDoc generates API documentation directly from TypeScript source and TSDoc comments, using the type information rather than parsing comments alone.

Effect is a library for building typed, composable programs where errors, dependencies and asynchrony all appear in the type signature.

fp-ts brings typed functional programming to TypeScript, with Option, Either, Task and the type-class hierarchy those structures come from.

TypeORM is a decorator-based ORM for TypeScript supporting both Active Record and Data Mapper patterns, with migrations, relations and a query builder.

MikroORM is a TypeScript ORM built on the Data Mapper, Unit of Work and Identity Map patterns, tracking entity changes and flushing them in one transaction.

InversifyJS is a full-featured inversion of control container for TypeScript, with decorators, scopes, tagged bindings and middleware.

ts-jest is a Jest transformer that runs TypeScript tests with full type checking during the test run.

io-ts provides runtime type validation built on fp-ts, representing decoding failures as an Either rather than by throwing.

tsd tests your TypeScript type definitions, asserting that types resolve as intended and that invalid usage is correctly rejected.

Serde is Rust's serialisation framework, converting between Rust data structures and formats such as JSON, YAML, TOML, MessagePack and many more via derive macros.

Tokio is the dominant asynchronous runtime for Rust, providing a work-stealing scheduler, async networking, timers, synchronisation primitives and task management.

Axum is a web framework from the Tokio team, built on Tower and Hyper, with routing and handler argument extraction driven entirely by the type system.

Actix Web is a mature, extremely fast Rust web framework with an extractor-based API, built-in middleware and first-class WebSocket support.

reqwest is the standard high-level HTTP client for Rust, with async and blocking APIs, JSON support, connection pooling, cookies and proxies.

clap is Rust's command-line argument parser, generating parsing, validation, help text and shell completions from a derived struct.

thiserror derives the std::error::Error implementation for your custom error enums, including display messages and source chaining.

anyhow provides a boxed, dynamically typed error for application code, with easy context attachment and a captured backtrace.

SQLx is an async, pure-Rust SQL toolkit that verifies your queries against a real database at compile time, without being an ORM.

Rayon turns sequential iterator chains into parallel ones by changing iter() to par_iter(), with work-stealing and guaranteed data-race freedom.

tracing provides structured, contextual diagnostics for Rust, recording spans of time as well as events — which is what makes async code debuggable.

The regex crate provides regular expressions with guaranteed linear-time matching, avoiding the catastrophic backtracking possible in most other engines.

Chrono provides date and time handling for Rust: timezone-aware timestamps, parsing, formatting and duration arithmetic.

Itertools extends Rust's iterators with dozens of adaptors the standard library omits: chunking, grouping, cartesian products, deduplication and more.

Criterion is a statistics-driven benchmarking library for Rust that detects performance regressions between runs and produces detailed reports.

proptest is a property-based testing library that generates random inputs to falsify stated properties, then shrinks any failure to a minimal case.

Tonic is a native Rust gRPC implementation built on Tokio, Hyper and Tower, with code generation from .proto files and full streaming support.

Ratatui builds rich terminal user interfaces in Rust with an immediate-mode API, layout system and a library of widgets.

indicatif renders progress bars, spinners and multi-progress displays for Rust command-line programs.

Mockall generates mock implementations of Rust traits and structs, with expectations on arguments, call counts and return values.

Diesel is a safe, extensible ORM and query builder for Rust that catches invalid queries at compile time through its type-level schema representation.

SeaORM is an async, dynamic ORM for Rust with relations, a query builder, migrations and entity generation from an existing database.

Hyper is a low-level, correct and fast HTTP implementation for Rust, supporting HTTP/1 and HTTP/2 for both clients and servers.

Tower defines a single Service abstraction — an async function from request to response — plus composable middleware for timeouts, retries, rate limiting and load balancing.

rand is Rust's random number generation crate, covering fast general-purpose generators, cryptographically secure sources and distribution sampling.

The uuid crate generates and parses universally unique identifiers, supporting versions 4 through 8 including the time-ordered v7.

nom is a parser combinator library for Rust that builds parsers from small composable functions, working on bytes or strings with zero copying.

Bevy is a data-driven game engine for Rust built on an Entity Component System, with a renderer, audio, input, physics integration and hot-reloading assets.

Entity Framework Core is Microsoft's official ORM for .NET, translating LINQ queries into SQL with change tracking, migrations and relationship management.

Dapper is a micro-ORM that maps SQL results onto objects with almost no overhead, leaving the SQL entirely under your control.

Serilog is a structured logging library for .NET that treats log events as data with named properties rather than formatted strings.

Polly is a .NET resilience library providing retry, circuit breaker, timeout, bulkhead isolation, rate limiting and fallback as composable policies.

FluentValidation defines validation rules in a strongly-typed fluent API, separate from the model itself.

xUnit.net is the most widely used .NET testing framework, with a minimal API, parallel execution by default and constructor-based test setup.

Moq is the most widely used .NET mocking library, creating test doubles for interfaces and virtual members with a LINQ-based setup syntax.

FluentAssertions provides readable, chainable assertions for .NET with failure messages that explain precisely what differed.

MediatR implements the mediator pattern for .NET, dispatching requests to handlers and decoupling callers from implementations, with a pipeline for cross-cutting behaviour.

AutoMapper maps between object types by convention, removing hand-written property assignments between entities and DTOs.

Json.NET (Newtonsoft.Json) is the long-established JSON library for .NET, with extensive customisation, LINQ to JSON and broad format tolerance.

Autofac is a mature .NET IoC container offering features beyond the built-in one: assembly scanning, decorators, property injection and fine-grained lifetime scopes.

Hangfire runs background jobs in .NET with persistent storage, automatic retries, scheduling and a web dashboard — no separate service required.

MassTransit is a distributed application framework for .NET, abstracting over RabbitMQ, Azure Service Bus, Amazon SQS and Kafka with sagas and routing built in.

Refit turns a C# interface into a REST client, generating the HTTP calls from attributes at build time with no reflection at runtime.

BenchmarkDotNet is a .NET benchmarking library that handles warm-up, statistics, memory measurement and multi-runtime comparison automatically.

Swashbuckle generates OpenAPI documents and a Swagger UI from ASP.NET Core controllers, models and XML documentation comments.

CsvHelper reads and writes CSV files in .NET with class mapping, type conversion and streaming for files larger than memory.

Bogus generates realistic fake data for .NET — names, addresses, emails, dates and text — for tests, seeding and demonstrations.

ImageSharp is a fully managed, cross-platform 2D graphics library for .NET, handling decoding, resizing, format conversion and drawing with no native dependencies.

NSubstitute is a mocking library for .NET with a deliberately minimal syntax, aiming to read as natural language rather than as configuration.

SignalR adds real-time bidirectional communication to ASP.NET Core, negotiating WebSockets where available and falling back automatically.

Quartz.NET is a full-featured job scheduler for .NET with cron triggers, persistent job stores, clustering and misfire handling.

Humanizer converts values into human-readable forms — relative dates, pluralisation, number words, byte sizes and cased strings.

Scrutor adds assembly scanning and decoration to the built-in .NET dependency injection container, without replacing it.

FastEndpoints is a REST API framework for .NET built on minimal APIs, using the REPR pattern — one class per endpoint with its own request and response types.

Mapperly is a source generator that produces object mapping code at compile time, with no reflection and no runtime cost.

NLog is a flexible .NET logging platform with rich routing rules, many targets and configuration that can be changed without recompiling.

The coroutine runtime for Kotlin, providing structured concurrency, dispatchers, channels and Flow for asynchronous and reactive programming.

Ktor is JetBrains' asynchronous framework for HTTP servers and clients in Kotlin, built on coroutines with a plugin-based architecture.

Kotlin's official serialisation library, generating encoders at compile time with a compiler plugin — no reflection, and Multiplatform-compatible.

Exposed is JetBrains' SQL library for Kotlin, offering both a typed DSL that mirrors SQL and a lightweight DAO layer.

Koin is a pragmatic dependency injection framework for Kotlin using a DSL, with no code generation, no reflection and no annotation processing.

MockK is a mocking library built for Kotlin, supporting coroutines, final classes, objects, extension functions and constructor mocking.

Kotest is a Kotlin testing framework with multiple spec styles, a large assertion library, property-based testing and data-driven test support.

Arrow brings typed functional programming to Kotlin: Either and Option for errors, typed error DSLs, optics, and resource-safe operations.

detekt is a static analysis tool for Kotlin, detecting code smells, complexity problems, potential bugs and style violations, with baseline support for existing codebases.

The official Kotlin Multiplatform date and time library, providing Instant, LocalDate, LocalDateTime and time zone handling across JVM, Android, iOS and JS.

Jetpack Compose is Android's declarative UI toolkit, describing interfaces as composable functions of state rather than as mutable view hierarchies.

Room is Android's persistence library, providing a typed abstraction over SQLite with compile-time query verification and Flow observation.

Hilt is Android's recommended dependency injection framework, built on Dagger with a simplified API and Android lifecycle-aware components.

SQLDelight generates typesafe Kotlin APIs from .sq files containing plain SQL, working across Android, JVM, iOS and JS.

Coil is an image loading library for Android and Compose Multiplatform, built on coroutines with automatic memory and disk caching.

Okio is a library for I/O in Kotlin and Java, offering buffered sources and sinks, a multiplatform filesystem abstraction and efficient byte handling.

Moshi is a JSON library for Kotlin and Java from Square, with a code-generating adapter option that respects Kotlin's null safety and default values.

Turbine is a small testing library for Kotlin Flows, providing a clear API for asserting on emissions, completion and errors.

ktlint is an anti-bikeshedding linter and formatter for Kotlin that enforces the official style guide with essentially no configuration.

JetBrains' extension of Jetpack Compose to desktop, iOS and web, letting one declarative UI codebase target several platforms.

Voyager is a navigation library for Compose Multiplatform with type-safe screens, nested navigators, tabs and integrated screen-scoped models.

A Kotlin Multiplatform key-value storage library wrapping SharedPreferences on Android, NSUserDefaults on Apple platforms and equivalents elsewhere.

Kermit is a Kotlin Multiplatform logging library from Touchlab that routes to Logcat on Android, os_log on Apple platforms and stdout elsewhere.

Ktorm is a lightweight Kotlin ORM with a strongly-typed DSL whose operators mirror SQL closely, plus an optional entity-object layer.

Store from Dropbox coordinates network fetching and local caching behind one API, providing single-source-of-truth data loading for Kotlin applications.

Paging 3 loads large datasets incrementally on Android, handling page requests, retries, placeholders and Compose integration.

WorkManager schedules deferrable, guaranteed background work on Android, surviving process death and reboots while respecting battery restrictions.

kotlinx-cli is JetBrains' Multiplatform command-line argument parser, with typed options, subcommands and generated help.

Alamofire is Swift's most widely used HTTP networking library, layering request building, validation, retry and authentication over URLSession.

TCA is a state management library for SwiftUI and UIKit, structuring applications around reducers, effects and composable feature modules.

Vapor is the leading server-side Swift web framework, built on SwiftNIO with routing, middleware, an ORM and authentication.

SwiftNIO is Apple's event-driven network application framework, providing the non-blocking I/O foundation for high-performance Swift servers.

GRDB is a SQLite toolkit for Swift offering raw SQL, a query interface, database observation and record types, with strong concurrency guarantees.

Apple's official library for building command-line tools in Swift, generating parsing, validation and help text from a declared struct.

Apple's package of production-grade data structures missing from the standard library: OrderedDictionary, OrderedSet, Deque and Heap.

Apple's package of sequence and collection algorithms: chunking, windows, combinations, permutations, unique and product.

Kingfisher downloads and caches images for Swift applications, with SwiftUI and UIKit integration, processors and prefetching.

SwiftLint enforces Swift style and conventions, with hundreds of configurable rules, autocorrection and custom rule support.

SnapshotTesting records views, data structures and any other value as a reference artefact and fails tests when the output changes.

Quick is a behaviour-driven testing framework for Swift and Objective-C; Nimble is its matcher library, providing expressive assertions and async expectations.

Swinject is a dependency injection framework for Swift, using a container with registered factories, object scopes and assemblies.

Realm is an embedded object database for Swift with live, auto-updating objects, reactive queries and optional device-to-cloud sync.

SwiftLog is Apple's logging API package, defining a common interface that libraries log against and applications route to a backend of their choice.

Factory is a compile-time-safe dependency injection container for Swift, using static properties and property wrappers rather than runtime type lookup.

Apple's build plugin that generates type-safe Swift client and server code from an OpenAPI document.

Lottie renders Adobe After Effects animations exported as JSON, natively and at runtime, on iOS and macOS.

Apple's open-source implementation of the CryptoKit API, providing hashing, HMAC, symmetric and public-key cryptography across Apple platforms and Linux.

Laravel is the most popular PHP framework, providing routing, an ORM, queues, caching, authentication, validation and testing in one coherent package.

Symfony is a set of reusable PHP components and a full-stack framework, favoured for large, long-lived enterprise applications.

Doctrine is a Data Mapper ORM for PHP with a Unit of Work, its own query language (DQL), and a migrations system.

PHPUnit is the standard testing framework for PHP, with assertions, test doubles, data providers and code coverage reporting.

PHPStan is a static analysis tool for PHP that finds type errors, undefined methods and impossible conditions without running the code.

Guzzle is PHP's standard HTTP client, with PSR-7 message support, middleware, concurrent requests and streaming.

Monolog is PHP's standard logging library, implementing PSR-3 with handlers for files, syslog, Slack, Sentry, Elasticsearch and dozens more.

Carbon extends PHP's DateTime with a fluent API, human-readable differences, localisation and testing helpers.

Pest is a testing framework built on PHPUnit with a concise closure-based syntax, expectations API and built-in parallel execution.

PHP-DI is a dependency injection container with autowiring, PHP-based configuration and support for the PSR-11 container interface.

Rails is a full-stack web framework covering routing, ORM, migrations, background jobs, mailers, caching and testing, built on convention over configuration.

RSpec is Ruby's behaviour-driven testing framework, with nested example groups, expressive matchers and built-in test doubles.

Sidekiq is a high-performance background job processor for Ruby, using threads and Redis to run many jobs per process.

RuboCop is a Ruby static code analyser and formatter, enforcing the community style guide with hundreds of configurable cops and autocorrection.

Sinatra is a minimal Ruby web framework — routes are blocks, there is no imposed structure, and the whole application can be one file.

Puma is a concurrent HTTP server for Ruby, using a thread pool and optional worker processes, and is the default server for Rails.

Devise is a flexible authentication solution for Rails built on Warden, providing registration, sessions, password recovery, confirmation and lockout as composable modules.

FactoryBot builds test objects from declarative factories, replacing static fixtures with composable, overridable definitions.

Pundit provides object-oriented authorisation for Rails using plain Ruby policy classes, one per model.

Kaminari is a pagination library for Rails and ActiveRecord, with scope-based paging, customisable views and support for non-ActiveRecord collections.