Regex Tester online free — large files supported

Test regular expressions against sample text and see matches.

Explanation

Regex Tester is a fast, free online tool for validators. Paste your input, click Run, and get results instantly via our API-backed processing.

Input

Output

Input Format

Plain Text

Example

Example Input

Pattern: \b[A-Z][a-z]+\b
---
Text: Alice met Bob in Paris last Monday

Example Output

Pattern: \b[A-Z][a-z]+\b
Matches: 4

  Match 1: 'Alice' at position 0-5
  Match 2: 'Bob' at position 10-13
  Match 3: 'Paris' at position 17-22
  Match 4: 'Monday' at position 28-34

Use Cases

Test and validate email address patterns before implementing form validation in production code
Debug complex regex patterns for parsing log files by testing against sample log entries
Validate phone number formats across different countries and ensure proper pattern matching
Test URL matching patterns to extract domain names, query parameters, or path segments from web addresses
Verify password strength regex rules meet security requirements before deploying authentication systems
Extract and validate data patterns from CSV or text files during data migration projects

How to Use Regex Tester

Paste or type your input data in the left text area
Click the Run button to process via the API
Copy the result from the output area

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Frequently Asked Questions

How is my data processed?

Data is processed on the server via API; we do not store content beyond processing and only log minimal technical metadata.

What is Regex Tester?

Regex Tester is a free online tool that processes your input via a secure API and returns results instantly.

Is Regex Tester free to use?

Yes, Regex Tester is completely free with no registration required. You can also access it via our API with a generous free tier.

Is my data safe with Regex Tester?