Live match highlighting, capture groups, all flags and a replace preview — test any regex on your own device.
//g
2 matches
Test string
Contact krupal@infytool.com or sales@example.org for details.
Capture groups (first match)
$1
krupal
$2
infytool
$3
com
Replace with (use $1, $2 for groups)
Runs in your browser. Files are never uploaded — you can go offline after the page loads.
How to use the Regex Tester
Type your pattern and toggle flags.
Matches highlight live in your test string.
Add a replacement to preview the result.
Easy to use
Drop files, pick options, download. Whole folders at once, no signup, no daily limit.
Best quality
The same engines the professionals use — SVGO, resvg, MozJPEG, libwebp, libavif — compiled to run in your browser.
Private & secure
Files are processed on your device and never uploaded. Close the tab and nothing remains anywhere.
See exactly what your pattern matches
Write a regular expression and watch every match light up in your test text as you type, with a breakdown of the
capture groups for the first match. Toggle the g, i, m, s, u and y flags, and add a replacement string (with $1, $2
back-references) to preview the substituted output.
It uses JavaScript’s own RegExp engine, so what works here works in your JS or TypeScript code — and it all runs in
your browser. To clean the matched text afterwards, try the Text Cleaner.
Frequently asked questions
Which regex engine is this?
JavaScript’s built-in RegExp — the same engine your browser and Node use — so what works here works in your JS/TS code.
How does replace work?
Type a replacement using $1, $2 (or $<name>) for capture groups and the result updates live. Invalid patterns show the error instead of crashing.
Most online converters upload your file to a server. InfyTool ships the actual encoders to your browser as WebAssembly instead, so processing happens inside your tab — faster for batches, and nothing to delete afterwards.
No upload, ever. Turn off Wi-Fi after the page loads and every tool keeps working.
No limits. No file-size cap, no queue, no watermark, no account.
Runs on your CPU. Batches use several cores in parallel; nothing is throttled.