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Regex Tester & Debugger — Test Regular Expressions Online Free

Test regular expressions in real time with interactive flags and match highlights.

Interactive Tool Workspace

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Processing Limits & Device Capabilities

Processed client-side in browser memory. Recommended maximum file size is 50 MB on desktop and 15 MB on mobile.

Zero Cloud Transmission: Zero bytes are uploaded to any server. File handling is constrained only by available device RAM.

How to Use Regex Tester & Debugger

  1. Enter your regular expression pattern in the Pattern box.
  2. Select active flags (g: Global, i: Case Insensitive, m: Multiline).
  3. Paste your test text in the workspace.
  4. View highlighted matches and captured group breakdowns in real time.

About Regex Tester & Debugger

Regex Tester provides instantaneous pattern validation for data scrapers, form validation rules, and string parsing scripts with safety limits.

Frequently Asked Questions

Are dangerous regexes safeguarded?

Yes! Execution runs with input length limits and timeout safeguards to prevent catastrophic backtracking.

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