Does this tester support ECMAScript 2018 named groups?

Yes, use the syntax (? ...) to name capture groups, which will appear in the groups array output just like they do in native browser environments.

How do I enable lookbehind assertions?

Lookbehinds are supported in the underlying ECMAScript engine since ES2018; simply write (?<=...) or (?!...) in your pattern and ensure the text context matches the assertion rules.

Why does my dot . not match newlines?

By default, . excludes newlines; add the s flag to enable dotAll mode, which allows the dot to match any character including line breaks.

What should I do after refining my regex pattern?

Use the generated code snippets to implement the logic directly, or move to our regex find and replace tool for batch processing multiple files or logs.

Regex Tester Online: Live Matches & Group Highlights

Q: Why does my dot . not match newlines?

By default, . excludes newlines; add the s flag to enable dotAll mode, which allows the dot to match any character including line breaks.

Q: What should I do after refining my regex pattern?

Use the generated code snippets to implement the logic directly, or move to our regex find and replace tool for batch processing multiple files or logs.

Test your regular expressions against sample text live. This tool uses the actual ECMAScript regex engine, supporting modern features like named groups (?<name>...) and lookbehind (ES2018+), and highlights every match group in real-time.

Regex Pattern:

g (global) i (ignore case) m (multiline) s (dotAll) u (unicode) y (sticky)

Sample Text:

Enter a pattern and text to see results.

Highlighted Matches:

Code Exports:

Python:

JavaScript:

Debug and Validate Regular Expressions Live

Automation developers and data engineers building scraping pipelines or log parsers need to validate modern ECMAScript regex features against their raw datasets immediately. This powerful online regex tester runs your patterns against the actual ECMAScript engine, ensuring compatibility and accuracy. You can verify complex extractions, including named groups and lookbehinds, without guessing the regex flavor. Whether you're parsing complex logs or extracting data from web pages, this tool provides instant feedback and detailed insights into your regex matches.

The interactive interface highlights every match group live as you type, giving you a clear visual representation of how your pattern interacts with your sample text. This rapid feedback loop is invaluable for refining patterns and ensuring they capture exactly what you intend, dramatically speeding up your development workflow.

How to Use This Regex Tester

Enter your regular expression in the pattern field and select the required flags (like `g` for global or `s` for dotAll).
Paste the sample text or log data you want to analyze into the content area.
Observe the live results: matches are instantly highlighted in the sample text while a detail panel lists each occurrence and its captured groups.
Inspect the groups array output for undefined values in un-captured slots or verify the exact index positions of matches.
Export working syntax instantly using the generated Python re.compile or JavaScript /pattern/flags snippet for easy integration into your projects.

FAQ

Q: Does this tester support ECMAScript 2018 named groups?: A: Yes, use the syntax (?<name>...) to name capture groups, which will appear in the groups array output just like they do in native browser environments.
Q: How do I enable lookbehind assertions?: A: Lookbehinds are supported in the underlying ECMAScript engine since ES2018; simply write (?<=...) or (?<!...) in your pattern and ensure the text context matches the assertion rules.
Q: Why does my dot . not match newlines?: A: By default, . excludes newlines; add the s flag (dotAll mode) to enable it to match any character including line breaks.
Q: What should I do after refining my regex pattern?: A: Use the generated code snippets to implement the logic directly, or move to our regex find and replace tool for batch processing multiple files or logs.