Test regex locally.
Zero proprietary code leaks.
Pattern is an offline development workbench. Evaluate regular expressions, inspect matches, transform string casings, encode/decode Base64 and URLs, and compare text diffs without sending confidential tokens or source code across the internet.
5 Dedicated In-App Screens
Complete tool suite running on native string evaluation engines.
Interactive Regex Engine
Real-time regex compiler with instantaneous match counter, match extraction list, case-insensitivity, and multi-line evaluation.
50+ Pattern Library
Categorized pattern catalog (Emails, IPv4/IPv6, ISO8601 Dates, Hex Colors, UUIDs, SemVer, HTML tags) with 1-tap test injection.
String Transformer
Case converters (camelCase, snake_case, kebab-case, UPPERCASE), Base64 enc/dec, URL enc/dec, and JSON quote escaping.
Text Diff Inspector
Side-by-side offline comparison between original (Text A) and modified (Text B) strings to pinpoint line-by-line additions and deletions.
Syntax & Grammar Cheatsheet
Comprehensive offline quick-reference covering character classes, greedy/lazy quantifiers, word boundaries, and capture group syntax.
Zero Telemetry Guarantee
Guaranteed zero network requests. Your proprietary strings, tokens, and payloads never leave RAM.