JavaScript regex tester

Test patterns, inspect captured groups and preview replacements with a stoppable browser worker.

JavaScript regex pattern, without slash delimiters

g · Globali · Ignore casem · Multilines · Dot allu · Unicoded · Match indices

Test text, up to 100,000 characters

The browser's JavaScript regex engine

Patterns run in a disposable worker. A 2.5-second execution deadline stops patterns that backtrack too long. Match positions count UTF-16 code units, as JavaScript does. Captures and replacement tokens use the current browser's native semantics.

More tools like this

JSON formatter and minifierValidate, format or minify JSON while preserving large numbers. Browse a source-aware tree, find keys and inspect duplicate-key warnings.Base64 encoder and decoderEncode text as Base64 or decode it back to text. Supports UTF-8 and URL-safe Base64.Image to Base64 converterConvert an image into a Base64 data URL, HTML image tag or CSS background. Preview it before copying the result.UUID generatorGenerate version 4 UUIDs individually or in batches. Inspect an existing UUID to check its version and structure.