43 developer tools & websites

Docs, debuggers and things that save an afternoon. Every developer site in the directory, each one checked by a person.

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Web Check

Web Check is the all-in-one OSINT and security tool, for revealing the inner workings of any website
- Developer
- Free
- web-check.xyz
Cheatography

Thousands of community-made cheat sheets for programming languages, tools and shortcuts, all printable.
- Developer
- Free
- cheatography.com
Cursify

A library of animated cursor effects for React and Next.js, from trails to spotlights, each with copy-paste code.
- Developer
- Free
- cursify.ui-layouts.com
Originkit

A library of animated website components, from text effects to scroll reveals, to copy into code or Framer.
- Developer
- Free
- originkit.dev
Staying

Paste code and watch it run step by step, with variables, arrays and the call stack drawn as it goes.
- Developer
- Freemium
- staying.fun
UI Ball

Small, lightweight loading spinners and other UI bits for the web, ready to copy as CSS, React or SVG.
- Developer
- Free
- uiball.com
Free for Developers

A long, maintained list of services with genuine free tiers for developers: hosting, databases, CI, email, monitoring and more.
- Developer
- Open source
- free-for.dev
Anime.js

A small JavaScript animation library with a homepage that shows off what it can do. Timelines, staggering and SVG morphing with a pleasant API.
- Developer
- Open source
- animejs.com
Bundlephobia

Type an npm package and see what it costs your users: minified and gzipped size, download time, and lighter alternatives, before you install it.
- Developer
- Open source
- bundlephobia.com
Can I email

Like Can I use, but for email clients. Look up any HTML or CSS feature and see whether Gmail, Outlook and Apple Mail will actually render it.
- Developer
- Free
- caniemail.com
dbdiagram.io

Type tables and relations in a tiny markup language and watch the entity-relationship diagram draw itself next to your code.
- Developer
- Freemium
- dbdiagram.io
Decker

A HyperCard-style multimedia sketchbook with 1-bit graphics. Draw cards, add buttons and a little scripting, and you have a zine, a game or a tool.
- Developer
- Open source
- internet-janitor.itch.io
Devhints

Hundreds of one-page cheatsheets for languages, frameworks and CLI tools, written to answer the question you have right now and nothing more.
- Developer
- Open source
- devhints.io
grep.app

Search a million public GitHub repositories at once, with regex, in milliseconds. The quickest way to see how real code uses a function or config option.
- Developer
- Free
- grep.app
Hoppscotch

Send REST, GraphQL and WebSocket requests straight from a browser tab. A fast, self-hostable alternative to Postman that opens instantly.
- Developer
- Open source
- hoppscotch.io
HTTP Cats

A cat photo for every HTTP status code, served at http.cat/404 and friends. Half joke, half the reference you end up linking in API docs.
- Developer
- Free
- http.cat
JWT.IO

Paste a JSON Web Token to decode its header and payload and check the signature. The first tab everyone opens when auth goes wrong.
- Developer
- Free
- jwt.io
Mockaroo

Describe the fields you need and get a thousand rows of believable fake data as CSV, JSON or SQL, from names and addresses to IBANs and car models.
- Developer
- Freemium
- mockaroo.com
React Bits

Over a hundred animated React components, from text effects to WebGL backgrounds, each with a live preview and props to play with before you copy it.
- Developer
- Open source
- reactbits.dev
readme.so

Click together a README from ready-made sections like installation, usage and license, edit them side by side with a preview, and copy the Markdown.
- Developer
- Open source
- readme.so
Shadertoy

Thousands of GPU shaders running live in the browser, from fractal landscapes to whole demoscene worlds in a few hundred lines. Fork any of them and tweak.
- Developer
- Free
- shadertoy.com
Transform

Paste JSON and get TypeScript types, a Go struct or a Zod schema back. Dozens of one-way converters between the formats you keep retyping by hand.
- Developer
- Open source
- transform.tools
Uiverse

A community gallery of buttons, loaders, toggles and cards made in plain CSS or Tailwind. Copy the code of any one you like, no attribution needed.
- Developer
- Open source
- uiverse.io
Wokwi

Wire an Arduino, ESP32 or Pico on a virtual breadboard, flash real firmware and watch LEDs blink and displays light up, with no hardware on your desk.
- Developer
- Freemium
- wokwi.com
Compiler Explorer

Type code on the left, watch the assembly appear on the right, colour-matched line by line, across dozens of compilers. The fastest way to see what yours actually does.
- Developer
- Open source
- godbolt.org
IT Tools

A drawer of small developer utilities — hashes, JWT decoding, cron parsing, colour conversion, QR codes — in one tidy interface you can also self-host.
- Developer
- Open source
- it-tools.tech
Public APIs

A gigantic curated list of free APIs, sorted by category, with auth and CORS support noted for each one.
- Developer
- Open source
- github.com
DevDocs

Documentation for hundreds of APIs in one fast, searchable, offline-capable interface. Entirely keyboard driven.
- Developer
- Open source
- devdocs.io
web.dev

Guidance on performance, accessibility and modern browser capabilities, straight from the Chrome team.
- Developer
- Free
- web.dev
Shields.io

Concise, consistent and legible badges for your README, generated from live data about your project.
- Developer
- Open source
- shields.io
crontab.guru

A cron schedule expression editor that translates five cryptic fields into a plain English sentence.
- Developer
- Free
- crontab.guru
patterns.dev

A free book on design patterns and component patterns for modern web apps, with runnable examples.
- Developer
- Free
- patterns.dev
Carbon

Turn source code into a beautiful image for slides and posts, with real syntax themes and window chrome.
- Developer
- Open source
- carbon.now.sh
explainshell

Paste a shell command and get every flag and argument annotated with the matching line from the man page.
- Developer
- Free
- explainshell.com
Refactoring Guru

Design patterns and refactorings explained with clear diagrams and code in a dozen languages.
- Developer
- Freemium
- refactoring.guru
QuickRef.ME

Dense, well-organised cheat sheets for languages, tools and commands. The one you keep in a pinned tab.
- Developer
- Open source
- quickref.me
regex101

Build, debug and explain regular expressions with a live match view and a step-by-step breakdown of every token.
- Developer
- Freemium
- regex101.com
roadmap.sh

Community-drawn learning roadmaps for frontend, backend, devops and more, with resources at every node.
- Developer
- Open source
- roadmap.sh
JSON Crack

Paste JSON, YAML or CSV and watch it explode into an interactive node graph you can actually read.
- Developer
- Freemium
- jsoncrack.com
Can I Use

Browser support tables for every web platform feature, with usage share so you know what you can actually ship.
- Developer
- Free
- caniuse.com
Learn Git Branching

The best way to finally understand rebase: an animated, level-based sandbox for real git commands.
- Developer
- Open source
- learngitbranching.js.org
CyberChef

The cyber swiss army knife: encode, decode, compress, hash and parse anything by dragging operations into a recipe.
- Developer
- Open source
- gchq.github.io
MDN Web Docs

The reference for HTML, CSS and JavaScript that actually gets updated. Documentation the whole web agrees on.
- Developer
- Free
- developer.mozilla.org

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