OPENVIST TOOLS · FREE TO USE
Regex Tester — JavaScript
Test a JavaScript regular expression locally, highlight matches and inspect numbered and named capture groups.
Runs locally in your browserJavaScript engine · 256 KiB text · 4 KiB pattern · 3-second limit. Indices use UTF-16 code units.
Uses your browser’s JavaScript RegExp engine, not Python, PHP or Rust. Enter a pattern without / delimiters. Flags: g, i, m, s, u, y. Without g, only the first match is returned. Positions are zero-based UTF-16 code units; end positions are exclusive. Null captures mean an unmatched group. Limits: 256 KiB text, 4 KiB pattern, 200 capture groups, 1,000 matches and 5 MiB output. The worker is terminated after 3 seconds; no partial report is returned.
Load an example or provide your input to begin.
Result
Highlighted matches
A vertical marker indicates a zero-length match. Capture values and positions are listed in the JSON report below.
Downloads contain your processed data. Review them before sharing.
What this tool does
Uses your browser’s JavaScript RegExp engine, not Python, PHP or Rust. Enter a pattern without / delimiters. Flags: g, i, m, s, u, y. Without g, only the first match is returned. Positions are zero-based UTF-16 code units; end positions are exclusive. Null captures mean an unmatched group. Limits: 256 KiB text, 4 KiB pattern, 200 capture groups, 1,000 matches and 5 MiB output. The worker is terminated after 3 seconds; no partial report is returned.
Use the example to understand the accepted input. Field names, when applicable, are literal. Inputs are not executed, and Sitemap Inspector never requests the listed URLs.
Worker processing stops after 3 seconds; results are limited to 5 MiB. Initial sitemap XML parsing runs locally before that worker timeout. Inputs and results are cleared when you reload the page. Nothing is executed from the supplied files.
A practical example
Extract version-like tokens from a small text and inspect capture groups using the browser’s JavaScript engine.
Example input
Pattern: v([0-9]+)\.([0-9]+)\.([0-9]+) Flags: g Text: OpenViST v0.5.0
What to expect
One match: v0.5.0; captures 0, 5 and 0. This pattern matches a spelling, not full semantic-version validity.
Use the controls above to enter this example. Load example may use a different sample; check the selected operation and options.
Continue with a related recipe
These scripts address related tasks. Review each recipe’s runtime, inputs, recorded tests and limits; its behavior may differ from this browser tool.