About Us

RegexMate is a free online regular expression tester. It exists for one reason: regex debugging is where text cleaning and log extraction go to die — a pattern that almost works, a capture group in the wrong place, a tab frozen solid by catastrophic backtracking. Getting from "almost" to "works" should take seconds, not an afternoon.

What the Tool Does

Paste a pattern and test text, and RegexMate shows you everything the engine sees. Three ideas shaped every design decision:

• Show the structure, not just the syntax. The pattern is parsed into an abstract syntax tree and drawn as a railroad diagram — alternations branch, quantifiers loop, capture groups box their contents with solid borders and numbers, non-capturing groups get dashed borders. You see the boundaries the parentheses really create.
• Support the whole workflow. Match lists every hit with its capture groups, Replace runs templates with $1 references, Split carves text at matches. One tab covers testing, cleaning and extraction.
• Make the danger visible. Nested quantifiers like (a+)+ are flagged the moment you type them, and every execution is timed — so catastrophic backtracking is caught before your tab freezes, not after.

Our Approach

We believe a debugging tool must itself be trustworthy. That is why the entire engine runs in your browser:

• No uploads. Your patterns and test text are processed locally with JavaScript and never sent to any server — safe for logs, customer data and source code.
• No sign-up. No accounts, no email walls, no watermarks.
• No stored history. Close the tab and everything is gone.

The Name

"RegexMate" pairs the tool with its purpose — a mate that reads your regex with you. The site is styled like a railway signal box because that is the mental model: your pattern is a track, characters ride it left to right, alternations switch points, quantifiers loop back around, and the signal goes green when the structure is sound. Every pattern deserves to be on the right track.

Get in Touch

Found a pattern that renders incorrectly, or have an idea that would speed up your workflow? We would love to hear from you — visit our contact page and drop us a line.