ToolwebHow to use this tool
- Enter text and a pattern without surrounding / delimiters.
- Choose g/i/m/s/u flags and a replacement.
- Inspect highlighting, captures, line/column locations and replacements.
Capture a code and number
- Input and settings
- A-123 · pattern ([A-Z])-(\d+) · replacement $1:$2
- Result
- A:123 · captures A, 123
Without g, only the first match/replacement is processed.
Processing rules and reading the result
Uses the browser’s JavaScript RegExp syntax. Indices are UTF-16 offsets; line/column fields help locate matches. Empty matches advance to prevent endless enumeration.
Limits and checks before use
Limits: 200,000 input characters, 500 pattern characters, 1.5 seconds and 1,000 matches. Long matches/captures may be truncated for display. PCRE/Python regex behavior may differ.
Common questions
What do cancellation and timeout do?
They terminate the worker, stopping regex execution. Review complex patterns on smaller inputs.