RegexLearn

regexlearn.com is a free, open-source platform that turns regular expressions from a black art into a skill you can pick up in an afternoon. Learn step by step in 21 languages, keep the cheatsheet nearby, and test your patterns live in the playground.

Features

• Step-by-Step Learning: Interactive lessons that progress from the basics to advanced patterns, one small step at a time. Matches light up as you type, and your progress is saved in your browser.
• Courses: Two lesson tracks are available: Regex 101 for fundamentals and Regex for SEO for practical, search-focused usage.
• Cheatsheet: A concise summary of regex syntax with a live example for every entry.
• Playground: A private, browser-based sandbox to write and test regex patterns. Everything runs locally; nothing you type is sent to a server.
• Shortcut Friendly: Move through lessons, toggle flags, and reveal answers from the keyboard.
• Works Everywhere: Responsive on phones and tablets, with right-to-left support for Arabic and Persian.

Supported Languages

Available in 21 languages:

Speak a language that isn't listed? Adding it is a single pull request: copy the en folder in src/localization/, translate the JSON files, and you've brought regex to every developer who reads in your language. Prefer to start a conversation first? Open an issue.

Translation Guidelines

• English is the reference. Translate from src/localization/en and keep exactly the same keys in every file.
• Leave code as it is. Text between backticks (`[a-z]`, `OK`) is rendered as code; don't translate it, and keep every pair of backticks.
• Keep the line breaks. \n marks a line break inside a lesson text; keep it in the same place.
• Match the lesson. Each step asks the learner to type a specific answer, so a translated instruction must still lead to that exact answer.

Development

Built with Next.js, React, TypeScript, and Tailwind CSS. The site is exported as static HTML.

Requires Node.js 20.9 or newer (the pinned version is in .node-version).

npm install   # install dependencies
npm run dev   # start the dev server at http://localhost:3003
npm run lint  # lint the project
npm run build # static production build in out/

Local environment variables belong in .env or one of Next.js's .env.*.local files. These files are ignored by Git and must not contain values intended for source control.

Contributing

RegexLearn is shaped by its community: lessons, translations, and fixes in this repo came from contributors around the world. Spotted a typo, a bug, or an awkward translation? A small pull request is all it takes to improve the experience for thousands of learners.

• Please target the main branch with your pull requests.
• main is production: every pull request merged into it is deployed to regexlearn.com automatically, so please make sure npm run build passes before opening one.

Our Sponsors

Sponsorship

RegexLearn is free for everyone, and sponsors are what keep it that way. Sponsorship puts your brand in front of a worldwide audience of developers at the exact moment they're learning. Want your logo up there? Get in touch.

License

This project is licensed under the MIT License. See the LICENCE file for details.