Developer
JSON Formatter / Validator
Validate, format and compact JSON without uploading your input.
Open toolRegex Tester
Inspect JavaScript regular-expression matches in a terminable browser worker.
Maximum 200,000 characters. Input is not stored.
Ready. Use Ctrl/⌘ + Enter to run.
Completed and failed run counts are stored only on this device.
How to use this tool
Enter text, a JavaScript pattern without slash delimiters and flags. Results include indexes and captured groups.
Supported input and limits
500-character pattern, 1,000-match limit and a 3-second execution deadline. Offsets are JavaScript UTF-16 indexes. Maximum main input: 200,000 characters.
Frequently asked questions
Does my input leave my browser?
No. A local worker processes it; text and files are not uploaded or stored.
Can a costly pattern freeze the page?
Processing runs in a disposable worker that is terminated after the time limit.
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