Regex Tester

Write a pattern, paste some text and see every match, group and explanation update as you type. Everything runs in your browser — the share link carries the whole session.

Regex quick reference

Regular expression

ECMAScript (JavaScript) flavor

/gm

Matching…

Test string

153 chars

Function

Matches are highlighted in the test string; details are under Match information. Switch to Substitution to replace matches, or List to output a template for each match.

Code generator

const regex = /(?<year>\d{4})-(?<month>\d{2})-(?<day>\d{2})/gm;
const str = "Release dates:\nv1.0 shipped on 2024-03-18 after a long beta.\nv1.1 followed on 2024-07-02, and v2.0 on 2025-01-27.\nNot dates: 2024-3-8, 20240318, 24-03-18";

for (const match of str.matchAll(regex)) {
  console.log(`Found "${match[0]}" at ${match.index}`, match.slice(1), match.groups);
}

Explanation

/(?<year>\d{4})-(?<month>\d{2})-(?<day>\d{2})/gm

(?<year>\d{4})Named Capture Group "year" (group 1)
- \d{4}matches a digit (equivalent to [0-9])
  - {4}matches the previous token exactly 4 times
-matches the character - (index 45) literally (case sensitive)
(?<month>\d{2})Named Capture Group "month" (group 2)
- \d{2}matches a digit (equivalent to [0-9])
  - {2}matches the previous token exactly 2 times
-matches the character - (index 45) literally (case sensitive)
(?<day>\d{2})Named Capture Group "day" (group 3)
- \d{2}matches a digit (equivalent to [0-9])
  - {2}matches the previous token exactly 2 times

Flags

gglobal — Find all matches instead of stopping after the first.
mmultiline — ^ and $ match at the start and end of each line, not only of the whole string.