Regex Tester Pattern Editor

Test a regex on your iPhone and see every match light up the moment you type it. Paste your text, write your pattern, and watch matches highlight character by character — no desktop, no compile step, no guessing. Most regex help on a phone is a static article you read. Regex Tester is a working engine: it runs your pattern through Foundation's NSRegularExpression, the same ICU syntax iOS itself uses, so what you see here is exactly what your app, script or config will do. Invalid pattern? You get a plain-English reason — unbalanced parentheses, an unclosed character class, a quantifier with nothing to repeat — instead of a cryptic engine dump. WHAT YOU GET - Every match highlighted inside your own test text, re-evaluated live as you type - A stats row with the match count, the total capture-group count and the flags currently active - Four flags toggled by tap: case-insensitive (i), multiline (m), dot-all (s), ignore-whitespace (x) - Capture-group inspection: numbered and named groups, each with its value and character range, plus the full text and range of every match - Replace preview: enter a replacement template using $1, $2, $0 or $& and watch the rewritten text update live - 19 ready-made patterns — Email, URL, IPv4, US Phone, Hex Color, ISO Date, Time 24h, ZIP Code, Credit Card, HTML Tag, Named Date, Whitespace, Integer, Decimal, Word, UUID, JWT Token, Slug, Hashtag - A search field and five filters across the library: All, Validation, Extraction, Web, Format - Copy any library pattern to the clipboard, or tap Use Pattern to load it with sample text straight into the Test tab - Copy your current pattern to the clipboard in one tap - A built-in ICU cheatsheet in six sections: Character Classes, Anchors & Boundaries, Quantifiers, Groups & References, Lookaround, Replacement Templates — plus engine notes and links to the ICU User Guide and Apple's NSRegularExpression reference - Saved patterns: keep a pattern together with its test text and flags, reload it in one tap, delete when you are done — up to 50 entries, stored locally on this device PERFECT FOR - Developers sanity-checking a pattern away from their machine - Data and log wranglers pulling IDs, dates or fields out of messy text - Students and self-taught coders learning regexp by watching it behave - Anyone writing validation rules for forms, imports or search filters WHY NOT JUST USE A WEBSITE? Online regex testers need a connection, and they want you to paste your text into someone else's server — a hard no when that text is a customer export, a log dump or anything under NDA. This runs entirely on-device, works on a plane or in a basement, and keeps a keyboard-friendly phone layout. PRIVACY Every pattern, test string and result is processed on your device and stored on your device. No account, no ads, no tracking, no upload — there is no server to send anything to. Optional local reminders can nudge you back to a pattern you left unfinished; switch them off in iOS Settings. FULL ACCESS Live matching, the 19-pattern library and the first two cheatsheet sections are free. Full Access unlocks capture-group inspection with ranges, the live replace preview, all six cheatsheet sections with engine notes and source links, and saved patterns. Three options, no free trial: - Weekly — com.levi.regextester.weekly, $9.99 per week, auto-renewing - Yearly — com.levi.regextester.yearly, $49.99 per year, auto-renewing - Lifetime — com.levi.regextester.lifetime, $89.99 one-off purchase, never renews Restore Purchases sits in the settings card on the Saved tab. Five tabs — Test, Groups, Library, Reference, Saved — in a dark interface with monospaced pattern fields and haptic feedback. Open the Test tab, paste the text that is giving you trouble, and write the pattern that fixes it. Terms of Use (EULA): https://web-levi.web.app/terms Privacy Policy: https://web-levi.web.app/privacy-policy Questions? [email protected]