Create a free account and get 10% off every order — for life. Applies automatically at checkout when you're logged in.
FairSoftware

Free tool

Regex Tester & Builder

Test regular expressions live, inspect capture groups, and preview replacements.

Matches

Order date: 2024-06-15, shipped 2024-06-18.

Capture groups

#GroupValue
1full match2024-06-15
group 12024
group 206
group 315
year2024
month06
day15
2full match2024-06-18
group 12024
group 206
group 318
year2024
month06
day18

Common patterns

Related free tools

This tool is free and unrelated to what we sell. FairSoftware supplies genuine one-off Microsoft licences — Office licences and Windows licences, delivered by email.

About this tool

Write a regular expression and see it match your text as you type. Every match is highlighted, capture groups and named groups are listed, and flags can be toggled without editing the pattern. A library of common patterns — email, URL, UK postcode, IPv4, dates, hex colours — gives you a tested starting point instead of a blank box.

How to use the Free Regex Tester & Builder

  1. Type or paste your regular expression (without the surrounding slashes).
  2. Toggle the flags you need: global, ignore case, multiline, dot-all, unicode.
  3. Paste the text you want to test against.
  4. Read the highlighted matches and the capture-group table underneath.
  5. Or pick a common pattern from the list and adapt it to your needs.

Frequently asked questions

Which regex flavour is this?
JavaScript (ECMAScript) regular expressions, as implemented by your browser. Most patterns are portable, but lookbehind and some Unicode property escapes differ between languages.
Is my text sent anywhere?
No. Matching runs in your browser with the native RegExp engine.
Why does my pattern match nothing?
Check the flags first — without the global flag only the first match is returned, and case sensitivity catches people out constantly. Invalid patterns show an error message instead.
Can it hang on a bad pattern?
Certain nested quantifiers can backtrack catastrophically. The tool guards long-running matches, but simplify the pattern if you hit that.

Related free tools

← Browse all free online tools