Regex

Regex Pattern Builder

Build JavaScript regex source from literal text or a character mode and quantifier, with clear case-insensitive usage guidance.

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Generated pattern

Your result will appear here.

Output is JavaScript pattern source only, without slash delimiters or flags. Case insensitive requires the i flag when using the generated pattern. Literal text is used only in Exact text mode.

Limits: 16,384 pattern code units, 200,000 text code units, 2,000 matches or split parts, and 4,000,000 output code units. User regex execution requires a local worker with a 1,500 ms timeout. Oversized results fail rather than being truncated.

Processed locally in your browser. Inputs and results are not uploaded or saved by this page.

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What does this tool do?

Build JavaScript regex source from literal text or a character mode and quantifier, with clear case-insensitive usage guidance. Code Station Regex tools use the JavaScript regular expression engine. Inputs: Literal text, Character matching mode, Quantifier, Case sensitivity. Outputs: Generated pattern.

How to use it?

Choose a character matching mode and quantifier. Enter literal text only for Exact text and choose case sensitivity. Choose “Build pattern”, then copy individual result values if needed. Clear removes all inputs and results and restores option defaults.