Build and test regular expressions visually
Use the regex builder to assemble a common pattern from structured parts, then test it against sample text. It is a quick way to start with a readable pattern before refining special cases in the regex tester.
How it works
- Choose a pattern type or add the tokens you need.
- Adjust boundaries, character classes, repetition, and flags.
- Test the generated expression against representative input before shipping it.
Capabilities and limits
- Builds common patterns such as slugs, identifiers, hex colors, versions, and keys.
- Shows a live expression you can copy into your project.
- Does not replace testing against the full range of production input.
Examples
Slug
^[a-z0-9]+(?:-[a-z0-9]+)*$Matches lowercase URL slugs such as release-notes-2026.
Semantic version
^v?\d+\.\d+\.\d+$Matches v1.2.3 or 1.2.3 without prerelease labels.
Frequently asked questions
What is the difference between the builder and tester?
The builder starts common patterns from controls; the tester is better for running a finished expression against larger sample text.
Should I always use anchors?
Use ^ and $ when the whole value must match. Leave them out when searching for a match within longer text.