Online Regex Tester
Test and debug regular expressions instantly with live matching, highlighting and flag support.
Flags
Preview
Matches List
0 foundMastering Regular Expressions
Regular Expressions (Regex) are powerful sequences of characters that define search patterns. They are essential for developers working with string validation, data scraping, and text transformation.
How to use this tool:
- 1. Enter your pattern in the regex input field (slashes are added automatically).
- 2. Choose your flags: i for case-insensitive matching or m for multiline mode.
- 3. Paste your target text into the "Test Text" area.
- 4. Review matches in the live preview and export them as needed.
Quick Syntax Guide
Frequently Asked Questions
Is my data secure?
Yes. This Regex Tester processes data locally. We do not store or transmit the text you test on our servers.
Which regex engine is used?
Our tool uses the JavaScript RegExp engine, which is standard for web-based pattern matching.
Can I export results?
Absolutely. Use the "Copy Matches" button or the "Share Result" feature to save your work.
Are lookaheads supported?
Yes, the engine supports both positive and negative lookaheads and lookbehinds in modern browsers.
Try Next
Other utilities you might find helpful
Regex Debugger
Understand regex step-by-step with explanations.
JSON Formatter
Format, validate, and minify JSON instantly.
Base64 Encoder/Decoder
Encode and decode Base64 strings and files.
SQL Explain Parser
Analyze SQL execution plans and optimize queries.
DOM Complexity Analyzer
Analyze HTML DOM structure, detect deep nesting, count nodes, and identify performance issues instantly.