Zephium

Zephium turns your iPhone into a portable regex workbench. Type any regular expression and watch every token — literals, anchors, quantifiers, lookaheads, capture groups, and more — light up with an instant, human-readable breakdown. Your test string updates in real time: matches glow in neon-cyan the moment a valid pattern lands, while unmatched regions stay dim so you can see exactly what's working and why. Toggle flags (global, case-insensitive, multiline, dot-all) and track every numbered and named capture group, all without leaving your phone.

Browse a built-in Catalogue of curated patterns spanning 26 categories — from network addresses and ISO dates to SemVer validation and multi-constraint lookahead chains. Open any entry directly in the Workbench, adapt it to your needs, then save it to your personal Vault with custom notes and an optional reference photo of the real-world source text. Export a polished pattern card to your Photos library and share it with your team in one tap.

Twenty structured lessons take you from literals and anchors all the way to catastrophic backtracking, POSIX extensions, and real-world log-line parsers — with inline workbench exercises so every concept clicks before you move on. Once you have the fundamentals, put them to the test across 30 timed challenges in three tiers — Apprentice, Journeyman, and Expert — with span-exact scoring that rewards precision, not luck.

Whether you're debugging a gnarly production pattern on the go or levelling up your regex skills one lesson at a time, Zephium is the workbench that fits in your pocket.