Regex Shuttle vs regex101

Regex Shuttle is a free browser-based tool for testing, explaining, and learning regular expressions. As users type, it highlights matches and displays match details, groups, and indices. Its explainer separates expressions into tokens and gives plain-English descriptions, while a library provides ready-to-use patterns to copy or open in the tester. A cheat sheet covers regex characters, quantifiers, anchors, groups, and flags. The tool can preview find-and-replace results in real time, including capture-group references such as $1 and $2. It uses JavaScript's built-in RegExp engine, so its behavior follows JavaScript regex behavior in browsers and Node.js. The maker says it supports capturing groups, lookahead and lookbehind assertions, named groups, and Unicode patterns. Regex processing occurs locally in the browser; patterns and test strings are not uploaded, collected, or shared with third parties. The maker says it continues working offline after its first load. No signup or email is required, and the interface is available in English and Chinese. The Free plan is free, with no limits or ads.

regex101 is an online workspace for building, testing and debugging regular expressions. Its editor supports PCRE2, JavaScript, Python, Golang, Java,.NET 10.0, Rust, POSIX ERE, POSIX BRE and legacy PCRE. Explanations show how parts of a pattern match according to the selected flavor, and a step-through debugger helps follow matching. Match results can be exported as JSON, JSON Lines, CSV or plain text. Developer options include HTTP APIs, an MCP server, editor links and a separately licensed parser package. The workspace API stores editor data but does not provide a remote matching endpoint. File loaders read text, bytes and supported documents locally in the browser; saving or sharing workspace input can send it to the workspace service. Free includes core tools, one test string and saved workspaces with an account. Pro costs €4.99 a month, billed yearly, and adds multiple test strings, substitution pipelines, advanced benchmarking, formatting and an ad-free workspace. Enterprise is a self-hosted option with documented deployment on Linux using Docker Compose, MySQL and Redis.