Free Regex Tester

What is this Regex tester?

A quick way to try JavaScript regular expressions with flags like g, i, and m. Paste sample text, run a test, and see matches highlighted in context along with captured groups. Great for building and debugging patterns for validation, parsing, and search.

How to use it

1. Enter a pattern and optional flags (e.g., g, i, m).
2. Paste text in the input area.
3. Click Test to highlight matches and list captured groups.

Tips

• Use g for global matches, i for case‑insensitive, m for multi‑line anchors.
• Escape backslashes in patterns (e.g., \\d for digit).
• Be careful with catastrophic backtracking on complex patterns.

Related tools

Privacy: runs entirely in your browser—no data is sent anywhere.