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Regex Tester

Test and debug regular expressions in real-time with pattern highlighting.

Test and debug regular expressions in real-time with pattern highlighting.

/
text.txt
plaintext·0 chars·1 lines
Ln 1, Col 1·UTF-8·LF
matches.jsonRead-Only
json·0 chars·1 lines
Ln 1, Col 1·UTF-8·LF

Regex Tester

UseDaily's free online regex tester lets you write and test regular expressions against sample text in real time. See all matches highlighted instantly, adjust flags on the fly, and debug your patterns without leaving the browser.

How to Use

Enter your regex pattern in the pattern field and set flags as needed. Paste your test text into the editor. Matches are highlighted and listed immediately as you type.

Who Is This For?

1

Developers

Build and debug regex patterns for validation, parsing, and search logic.

2

Data Engineers

Test extraction patterns against raw text before running them in production pipelines.

3

Content Editors

Use regex to find and verify patterns in large text blocks.

Key Features

Real-Time Matching

Highlights all regex matches in the input text as you type your pattern.

Flag Support

Supports g (global), m (multiline), i (case-insensitive), and other standard flags.

Match Inspection

Lists all captured groups and match positions for detailed debugging.

Privacy Focused

All processing happens in your browser. Your data is never sent to any server.

Frequently Asked Questions

Yes. UseDaily's regex tester is completely free with no account required.
It uses JavaScript's native RegExp engine, which supports ECMA-262 syntax including lookahead, named groups, and Unicode mode.
Yes. Enable the 'm' flag to match ^ and $ at line boundaries rather than string boundaries.
Yes. The editor supports all special regex characters and auto-escapes them when needed.