Regex Tester

Test regular expressions and highlight matches in text.

Pattern

Flags

Test string

Result

Matches will be highlighted here.

What is Regex Tester?

Test JavaScript regular expressions against sample text. Matches are highlighted. Use for debugging patterns.

1. Enter a regex pattern and optional flags (g, i, m).

2. Enter or paste test text. Matches will be highlighted below.

Generate regular expressions from common patterns.

Explain regular expressions in plain language.

Compare two texts and see differences.

Remove duplicate lines from text.

Sort lines of text alphabetically.

Count words, characters, and lines.

Format, validate, and beautify JSON with syntax highlighting.

Test regular expressions and highlight matches.

Encode text to Base64.

Generate UUID v4 identifiers.

Decode and inspect JWT header and payload.