Developer / Debugging
Regex Tester
Test regular expressions instantly with live match feedback and editable text input. Test patterns, toggle flags, inspect capture groups, preview replacements, and see matches highlighted in real time.
3
Matches
gm
Flags
26
Pattern chars
Valid
Regex state
Loaded sample regex
Highlighted matches
Replacement result
Match details
Why this one is useful
Seeing matches highlighted in context is much faster than guessing whether a pattern worked from a single true or false.
Replacement preview makes the tool useful for cleanup and transformation tasks, not just validation.
Capture groups, named groups, and flag toggles keep the feedback loop tight, which is the whole point of a good regex tool.
Common uses
Validating IDs, routes, and filename patterns.
Extracting values from logs, copied responses, or pasted text.
Testing multiline and case-insensitive search rules.
Previewing text replacements before writing application code.
Why this page has value
Regex pages only become worth bookmarking when they show context, captures, and replacement behavior clearly. This page is built to shorten the loop between writing a pattern and trusting the result.
Workflow notes
Most regex work is iterative. You tweak flags, check the highlighted matches, inspect capture groups, and confirm the replacement result before that pattern ever reaches production code.
Privacy and trust
Patterns and test input stay in the browser, which makes the page safer for copied logs, sample records, support text, and internal validation rules.
Can I preview replacements as well as matches?
Yes. The tool includes a replacement preview so you can validate cleanup logic instead of testing only whether a pattern matches.
Does it show capture groups?
Yes. Both numbered groups and named groups are surfaced in the match detail panel.
Is this useful for multiline or case-insensitive patterns?
Yes. Flag controls let you test common regex modes without rewriting the pattern each time.
Related tools
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