RegExr is an online tool to learn, build, & test Regular Expressions (RegEx / RegExp).
regex101: build, test, and debug regex
Regular expression tester with syntax highlighting, explanation, cheat sheet for PHP/PCRE, Python, GO, JavaScript, Java, C#/.NET, Rust.
Regex Crossword
A crossword puzzle game using regular expressions. Earn achievements completing puzzle challenges. Easy tutorials for people new to regular expressions.
Fast regex search: indexing text for agent tools · Cursor
How we're building indexes for regular expression search so agents can find text in large monorepos without the 15-second ripgrep waits.
brevity1swos/rgx
regex101 for the terminal — real-time matching, 3 engines, capture groups, replace mode, syntax highlighting, plain-English explanations, undo/redo, mouse support. Written in Rust.
A DEVELOPER PROVED THE REGEX YOU'VE WRITTEN A THOUSAND TIMES IS SECRETLY A COMPILER AND THAT ALMOST NO ONE WHO USES THEM HAS ANY IDEA WHAT ACTUALLY RUNS 36 minutes from Paul Wankadia, the engineer behind a regex engine that compiles your pattern straight down to raw machine code https://t.co/pMhg9AxYbJ
A DEVELOPER PROVED THE REGEX YOU'VE WRITTEN A THOUSAND TIMES IS SECRETLY A COMPILER AND THAT ALMOST NO ONE WHO USES THEM HAS ANY IDEA WHAT ACTUALLY RUNS36 minutes from Paul Wankadia, the engineer behind a regex engine that compiles your pattern straight down to raw machine code… https://t.co/XgyFxNmImW pic.twitter.com/pMhg9AxYbJ— slash1s (@slash1sol) June 5, 2026
le0pard/re2js
RE2JS is the JavaScript port of RE2, a regular expression engine that provides linear time matching
RegEx match open tags except XHTML self-contained tags
I need to match all of these opening tags: <p> <a href="foo"> But not self-closing tags: <br /> <hr class="foo" /> I came up with this and wanted to make
Markdown Guide
A free and open-source reference guide that explains how to use Markdown.
BurntSushi/ripgrep
ripgrep recursively searches directories for a regex pattern while respecting your gitignore
Automator User Guide for Mac
Learn how to use Automator on your Mac to automate much of what you do on your computer.
Semble: Fast and Accurate Code Search for Agents
Fast and Accurate Code Search for Agents. Uses ~98% fewer tokens than grep+read
Compiling Match Statements to Bytecode
Full pipeline deep dive for purple garden: AST, BB SSA IR, Bytecode, Optimisations
bradleyjkemp/grpc-tools
A suite of gRPC debugging tools. Like Fiddler/Charles but for gRPC.