Regex Tester
Test JavaScript regular expressions with flags, highlights, capture groups, and replacement output.
Matches
4
Groups
8
Flags
gm
Pattern
Flags
Results
Regex compiled
4 matches found.
/\b(?<tool>RavensMove|JSON Formatter|Regex Tester)\b/gm
Highlight
Matches
RavensMove
JSON Formatter
Regex Tester
Regex Tester
Replacement Preview
[RavensMove] ships a [JSON Formatter] and a [Regex Tester].
Use the [Regex Tester] to check groups, match indexes, and replacement output.What is a Regex Tester?
A regex tester runs a regular expression against sample text and shows where the expression matches. It is useful for checking validation rules, parsers, search filters, log patterns, and text cleanup rules before moving the pattern into code.
This tester uses the JavaScript regular expression engine in your browser. Enter the pattern without surrounding slash delimiters, choose the flags you need, and inspect matches, indexes, capture groups, named groups, and replacement output.
JavaScript Regex Flags
gfinds every match instead of stopping after the first match.iignores letter case.mlets^and$match line starts and line ends.slets.match newline characters.uenables Unicode-aware matching.ymatches from the regex engine’s current sticky position.
Regex Tester Use Cases
- Validate emails, slugs, IDs, dates, or log fragments.
- Extract capture groups from text before writing parser code.
- Preview a replacement string before using
String.prototype.replace. - Compare case-sensitive and case-insensitive matches.
For adjacent developer data work, use the JSON Formatter to validate and inspect API payloads.
If you need to encode or decode text values before matching them, use the Base64 Encoder Decoder.