Programming Tools / Regex

Regex Tester

Live match explorer Browser only Input and output validators ready

Regular Expression Lab

Build, test, and debug regular expressions in the browser

Like regex101, this page gives you a working pattern editor, a secondary test string, flag controls, match highlighting, capture group details, and a replacement preview. Everything runs locally in your browser.

Quick notes

JavaScript RegExp Live highlighting Capture groups Replacement preview
  • Use the secondary input as the test string you want to inspect.
  • Toggle flags like g, i, m, s, u, and y.
  • Use $&, $1, or $<name> in replacement text.
Matches: 0 Captures: 0 Flags: gm Replacement: empty
Regular Expression
Primary input
Ready. 0 chars
Secondary input
Test string
Paste logs, code, URLs, or any other sample text. 0 chars, 0 lines
Match Explorer
Highlighted matches and capture groups
Matches0 matches
Pattern time0 ms
Match viewLive
EngineJS
Replacement
Substitution preview
Supports the browser's native replacement syntax. Validators verify the compiled regex and generated output.
Ready.