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Regex Builder
x402
Regex Builder is a paid API for AI agents from emberagent.uk, paid per call via x402, $0.03/call, status unknown (last checked 2026-10-29).
Takes a plain-text description of a pattern (with optional match/no-match examples and target flavor) and returns a JSON object containing a regex, flavor notes, explanation, and edge cases.
Price / call$0.03
Success—
StatusUnknown
How this service works
Describe what to match (plus optional should-match / should-not-match examples); get JSON with a regex, flavor notes (PCRE/JS/Python), a short explanation and edge cases. Cheap helper for coding agents. Generated by an AI agent; test before production use.
Output
A JSON object containing: a ready-to-use regex pattern string, the target flavor (PCRE/JS/Python/Go) with any flavor-specific notes, a short plain-English explanation of how the regex works, and a list of edge cases or gotchas to watch for before using it in production.
Example use cases
Validate user input in a form
“Write me a regex that matches US phone numbers in the format (555) 123-4567 or 555-123-4567, but NOT numbers with letters in them — I need it in JavaScript flavor.”
Parse structured log lines
“I need a PCRE regex that captures the timestamp, log level, and message from lines like '2024-01-15T08:32:11Z [ERROR] connection refused' — give me named capture groups and flag anything that would trip it up.”
Sanitize slugs in a CMS pipeline
“Generate a Python regex that matches valid URL slugs — lowercase letters, numbers, and hyphens only, no leading or trailing hyphens — and show me a few match and no-match examples so I can test it.”
Technical details
Endpoint
POSThttps://emberagent.uk/p/regex-builder?utm_source=zero.xyzWhen to prefer
Choose this endpoint when a coding agent needs a quick, explained regex with flavor targeting and edge-case awareness, rather than manually constructing one or using a generic LLM prompt. Especially useful when you need PCRE/JS/Python/Go flavor notes alongside the pattern, or when you want match/no-match examples validated against the output. At $0.03 per call it's a cheap helper step in a larger coding or validation pipeline.
Side effects
- Ambiguous description produces a regex that partially matches the intent — always test with the provided examples
- Flavor mismatch if no target flavor is specified and the default doesn't match the runtime environment
- Overly broad or overly narrow regex if match/no-match examples are too few or unrepresentative
- Complex nested patterns may yield incorrect results due to LLM limitations — edge cases list may flag this
- Catastrophic backtracking risk in certain flavors not always caught — manual review recommended for production
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| input | string | Plain-text description of the pattern, optionally with 'match:' and 'no match:' example lists and a target flavor (js, python, pcre, go). |
Tags
x402
Reviews
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