Online regex tester and debugger with real-time match highlighting, detailed explanations, substitutions, unit tests, benchmarking, and code generation. Supports PCRE2, JavaScript, Python, Go, Java, .NET, Rust, POSIX ERE, and POSIX BRE.
RegExr: Learn, Build, & Test RegEx
RegExr is an online tool to learn, build, & test Regular Expressions (RegEx / RegExp).
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.
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.
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
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.
A new era for software testing - <antirez>
Antithesis: autonomous software testing
Try the Antithesis autonomous testing platform and find bugs in your software with perfect reproducibility
MirrorCode: A benchmark for real-world software projects
Semble: Fast and Accurate Code Search for Agents
Fast and Accurate Code Search for Agents. Uses ~98% fewer tokens than grep+read
GoogleChromeLabs/wpt-gen
A CLI tool to analyze feature specs and generate the required web platform tests
Javascript unit testing tools
I have compared1 few different tools for unit testing Javascript code. The frameworks I looked intowere QUnit, Mocha JS, tape, AVA, Jasmine, Karma and Jest. ...