# Regex Explainer

Explain any regular expression, and catch the ones that can hang.

**Why delegate it:** Whether a pattern backtracks catastrophically depends on nested quantifier structure that is unreliable to eyeball — and getting it wrong ships a denial-of-service vector in a validator.

Site: https://regex-explainer-omega.vercel.app

## Tools

### `regex_explain` — Explain a regex and check it for ReDoS

Explain a regular expression in plain English and detect catastrophic backtracking. ALWAYS call this before putting a pattern where it will run against untrusted input: (a+)+$ looks harmless and takes minutes of CPU on a failing 30-character input. Also flags missing anchors, unescaped dots, ranges like [A-z] that span punctuation, and alternation precedence mistakes. Check hasBlockingIssue first.

Direct endpoint: `https://regex-explainer-omega.vercel.app/api/v1/explain`

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Via the aggregator: `https://gumballtools.com/api/mcp`
Direct: `https://regex-explainer-omega.vercel.app/api/mcp`