Regex Tester & Pattern Builder

Test regular expressions live with highlighted matches and groups.

Write a regular expression and watch every match light up in your text instantly — build, test, and debug patterns right on your iPhone, with no compile step and no guesswork.

Regex Tester turns your phone into a full regex workbench: live highlighting, capture groups, a replace preview, a searchable pattern library, and a built-in syntax reference.

WHAT YOU CAN DO • Live matching — type a pattern and see every match highlighted in real time as you edit • Capture groups — numbered and named groups broken out with exact ranges and colour coding • Replace preview — apply a replacement template and see the rewritten text instantly • Flags on tap — toggle case-insensitive, multiline, dot-all, and ignore-whitespace modes • Pattern library — a searchable set of ready-to-use patterns for email, URLs, dates, and more • Syntax reference — a built-in cheatsheet for tokens, quantifiers, lookarounds, and groups • Save your work — bookmark the patterns you rely on and reload them in one tap • Plain-English errors — clear explanations when a pattern will not compile

HOW IT WORKS

1. Type or paste a pattern and your test string
2. Watch matches highlight and groups break out live
3. Save, copy, or reuse patterns straight from the library

PRIVATE BY DESIGN Your patterns and test text never leave your device. No accounts, no ads, no tracking.

FULL ACCESS Full access to every feature is available through a subscription — choose weekly, yearly, or a one-time lifetime unlock.

Download Regex Tester and make regular expressions simple.

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