Regex Test Mcp

Local MCP server that runs JavaScript regex patterns through the real JS engine, returning exact match offsets, groups and replace results.

What you can do

• Test a pattern against text and get matched status, first match, start and end offsets, capture groups and named groups
• Find all non-overlapping matches, always global and safe against zero-width loops
• Apply replacements with $1, $ and $& syntax and get the new string plus a replaced flag
• Rely on actual JS semantics for lookahead, anchors, named groups and Unicode escapes instead of model guesses

When to use it

Useful when an assistant needs to verify regex behavior rather than describe it from memory: checking whether a pattern matches, getting correct group indices for nested captures, or confirming replacement output before it goes into code.

Requirements

Runs as a local stdio process, typically launched with npx from the npm package @mukundakatta/regex-test-mcp, so Node.js and network access for the first install are needed. No authentication, environment variables or headers are declared.