21 languages · 466 libraries · 2004+ examples
Know what to reach for,
and why
Not another API reference. Guides to what each language and library is actually for — where it fits, what it competes with, and the trade-offs you usually discover six months in.
How it works
The same structure on every page
So you always know where to look, whichever language or library you land on.
Honest trade-offs
Each language guide states what it is genuinely good at and genuinely bad at — the GIL, Java's startup cost, Rust's learning curve. Choosing well means knowing the price.
When to use, when not to
Library pages answer the real question. Concrete situations where it fits, situations where it does not, and the alternatives worth weighing against it.
Code that shows the idiom
Annotated examples of how the language is actually written, plus the pitfalls that catch everyone — mutable defaults, N+1 queries, dangling references.
Guides
Languages
History, key facts, strengths, trade-offs, idiomatic code, a learning path, and the mistakes everyone makes.
Python
84 libraries
The readable general-purpose language that became the default for data, AI and automation.
Java
74 libraries
The enterprise workhorse — thirty years old, still runs a large share of the world's back ends.
JavaScript
59 libraries
The only language that runs natively in every browser — and, since Node.js, on the server too.
TypeScript
28 libraries
JavaScript with a type system bolted on top — all the reach, far fewer runtime surprises.
C
30 libraries
The portable assembler that every other language is eventually implemented in.
C++
43 libraries
Zero-overhead abstraction — you pay only for what you use, and what you use is fast.
C#
28 libraries
Microsoft's flagship language — pragmatic, feature-rich, and no longer Windows-only.
Go
28 libraries
Deliberately small. Compiles in seconds, deploys as one binary, handles concurrency without ceremony.
Rust
28 libraries
Memory safety without a garbage collector — the compiler proves your code is sound before it runs.
Kotlin
28 libraries
Java's pragmatic successor — null safety, coroutines and half the boilerplate, on the same JVM.
Swift
19 libraries
Apple's modern systems-and-apps language — safe by default, fast, and increasingly cross-platform.
PHP
10 libraries
Powers a large share of the web — and the modern version is nothing like the one people remember.
Ruby
10 libraries
Optimised for programmer happiness — and, with Rails, for shipping a product faster than anyone expects.
Dart
Guide only
Google's language for Flutter — one codebase compiled to native mobile, desktop and web.
Scala
Guide only
Object-oriented and functional programming unified on the JVM — powerful, and demanding.
Elixir
Guide only
Modern syntax on a runtime built for systems that are not allowed to go down.
SQL
Guide only
Describe the result, not the steps — the most widely used language in software, by some distance.
R
Guide only
Built by statisticians for statistics — and still the place new methods appear first.
Lua
Guide only
A few hundred kilobytes of scripting language, embedded in more software than you realise.
Haskell
Guide only
Purely functional and lazily evaluated — where the type system does most of the arguing.
Zig
Guide only
A C replacement with no hidden control flow, no hidden allocations and no preprocessor.
Catalogue
Popular libraries
A cross-section — each with installation, worked examples, best practices and the alternatives worth weighing.
Requests
The HTTP client that made Python's networking approachable — synchronous, readable, everywhere.
Web & HTTP5 examplesReact Query
Server state management — caching, revalidation, retries and background updates for data you fetch.
Web & HTTP5 examplesSpring Boot
The default way to build a Java service — auto-configuration over a vast, mature ecosystem.
Web & HTTP5 examplesPandas
The dataframe library that made Python a serious tool for data analysis.
Data & Analytics5 examplesSQLite
A complete SQL database in a single file, embedded directly in your process.
Databases & Caching7 examplesTailwind CSS
Utility classes that keep styling in the markup and the CSS bundle small.
UI & Graphics6 examples
About
Common questions
What is this site for?
Documentation tells you how a library works once you have already chosen it. This site is for the step before that: understanding what a language or library is actually for, what it competes with, and whether it fits your problem. Every page is written to be read start to finish, not searched for one API call.
How is this different from the official docs?
Official docs are authoritative and rarely comparative — they cannot tell you to use something else. Each library page here adds a plain summary, concrete situations where the library is the right call, situations where it is not, and named alternatives with the reason they differ. Then it links you to the official documentation for the details.
Is the content free?
Yes, all of it, with no account required. The site is supported by advertising.
How current is this?
Language guides cover releases through 2025 and note where a feature is recent enough that older tutorials will disagree. Library entries describe stable, widely-used versions. Where a library's API changed significantly between major versions, the page says so — that is usually the thing that costs people an afternoon.