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Regex Tester Online — Free Tool

Develop and test Regular Expressions (Regex) in real-time against custom sample texts with visual highlighting.

/
/g
Tip: Enable g to find all matches.
Matches
12 matches
Showing up to 12 matches
Highlighted preview
Paste your test string here. Try a pattern like: \b\w+\b
Match list
#1
0–5
Paste
#2
6–10
your
#3
11–15
test
#4
16–22
string
#5
23–27
here
#6
29–32
Try
#7
33–34
a
#8
35–42
pattern
#9
43–47
like
#10
50–51
b
#11
52–53
w
#12
55–56
b
Privacy note: All processing happens entirely in your browser. No data is sent to our servers.

About this tool

Regular expressions describe text patterns for search, validation, and extraction. This tester runs your pattern against sample text and highlights matches, helping you refine syntax before shipping validation rules to production.

Test flags such as global or case-insensitive matching, and iterate quickly when building parsers for emails, IDs, or log lines. Processing stays in the browser so proprietary data does not need to leave your machine.

Common use cases

  • Validating form input patterns before deployment
  • Extracting fields from log or CSV samples
  • Learning regex syntax with immediate visual feedback

How to use

  1. Paste or type your input in the tool panel above.
  2. Choose formatting or conversion options if available.
  3. Copy the output for use in your document or project.

This page is available at /tools/regex-tester/.

Related keywords

  • regex tester
  • regular expression tester
  • regex match
  • regex flags
  • regex tool

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FAQ

What is Regex Tester?

Regex Tester is an online developer tool that develop and test Regular Expressions (Regex) in real-time against custom sample texts with visual highlighting.

How do I use the Regex Tester?

Paste your code, JSON, token, or query into the editor, run the tool, and copy the formatted or converted result into your project.

Is this tool free?

Yes—this tool is free to use with no account required.

Does it run locally in the browser?

Yes. Calculations and transformations run in your browser—your input stays on your device.