regex101 vs RegExr

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.

RegExr is a free web tool for learning, building, and testing regular expressions. It supports JavaScript and PHP/PCRE expressions, with results that change as you type. Hovering over a match or expression reveals details, and the Explain tool describes an expression in plain English. Tests mode lets users assemble examples that an expression should match or reject. Replace and List produce custom outputs, while Details shows capture groups. Learning resources include a cheatsheet, reference, help pages, and examples. Users can search and rate Community Patterns, then save and share expressions. Signing in keeps favorites and patterns in My Patterns. A saved expression gets a public link, and a Community-shared copy cannot be edited or deleted. The listed RegExr plan costs nothing. The project README credits Grant Skinner and gskinner.com as creators and identifies this version as GPL v3 licensed. It directs issue and feature requests to GitHub and regular-expression questions to Stack Overflow.