KoguNavi

KoguNavi tool

Regex Tester

Try a JavaScript regular expression against sample text and inspect matches, indexes, capture groups, and replacement output.

Local in browser

Runs in your browser for this tool.

Current tools are designed to run in your browser. As a general habit, avoid pasting passwords, private keys, or production secrets into any website.

Flags

Matches

Matches with indexes, capture groups, optional named groups, simple highlights, and an optional replacement preview.

What it helps with

  • Test a pattern against sample text
  • Inspect capture groups
  • Preview simple replacements before using them elsewhere

How to use

  1. Enter a JavaScript regular expression pattern and choose flags.
  2. Paste sample text and optionally add replacement text.
  3. Review matches, indexes, capture groups, highlights, and the replacement preview.

Examples

Capture key values

Input

{"pattern":"(?<key>\\w+)=(\\d+)","flags":"g","text":"id=42 count=7","replacement":"$1: $2"}

Output

id=42, count=7

Good to know

  • JavaScript regex syntax may differ from other languages.
  • Some patterns can be slow in the browser.
  • Shows the first 500 matches.
  • This tool is for testing, not security validation.

FAQ

Which regex syntax is used?
This tool uses JavaScript regular expression syntax.
What happens with invalid patterns?
Syntax errors are shown as readable messages without crashing the page.
Does this validate regex security?
No. It is for interactive testing and debugging, not security validation.

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