Regex Tester
Test a regular expression against text, inspect matches, and catch syntax errors locally in your browser.
Quick answer
Regex Tester helps estimate the result from your inputs in the browser. Use the output as a planning number, then compare it with your records, provider terms, or official guidance before making a final decision.
Patterns and text stay in your browser. Avoid overly complex expressions on very large text because JavaScript regular expressions can be slow.
Calculator
Results update as you type
Matches found
Review the matching values before using this expression in a filter, automation, or data-cleaning step.
Breakdown
Formula
The math behind the result
matches = all text segments that satisfy pattern + flags
How it works
A clean flow from input to answer
- 1Enter a pattern and optional flags such as i or m.
- 2Paste text to test against the expression.
- 3Review the first 100 matches before using the pattern elsewhere.
FAQ
Common questions
Which flags can I use?
Use standard JavaScript flags such as g, i, m, s, u, v, y, or d.
Does this send my text anywhere?
No. Matching happens locally in your browser.
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