# Regex Builder from Natural Language

> Regex Builder from Natural Language is a paid API for AI agents from dev-5090-box.tailfb4c1f.ts.net, paid per call via x402, $0.02/call, status unknown (last checked 2026-10-12).

Converts a plain-English description of a pattern into a regex and a matching test string

## Facts

- Endpoint: POST https://dev-5090-box.tailfb4c1f.ts.net/v1/regex-build?utm_source=zero.xyz
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-12
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/regex-builder-from-natural-language-0db7a59b
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_W7o5evJ3Ns2oEvF-dUN75

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability regex-builder-from-natural-language-0db7a59b -d '<json body>'
```

Example prompt: Build me a regex that matches email addresses, and give me a test string that it should match.

## When to prefer this

Choose this endpoint when you need a quick, ready-to-use regex generated directly from a plain-English description without having to write or debug patterns manually. It's ideal for developers prototyping validation logic, agents building dynamic input sanitizers, or tools that need to generate and immediately test a regex in one round-trip call. Prefer it over general-purpose chat endpoints when you want a minimal, structured response (just the regex + test string) rather than a verbose explanation.

## Known failure modes

- Ambiguous natural language description may produce an incorrect or overly broad regex
- Very complex multi-rule patterns may result in a regex that partially mismatches edge cases
- The test string returned may not cover all branches of the regex
- Model may occasionally hallucinate invalid regex syntax
- Upstream LLM unavailable or GPU resource exhausted returns a 5xx error

## How this service works

Build a regex from a natural-language description. Returns just the regex + one test string.

## Output

Returns a regular expression pattern string and a single example test string that the regex matches, with no extra explanation or prose.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "usage": {
   "type": "object"
  },
  "choices": {
   "type": "array"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/regex-builder-from-natural-language-0db7a59b/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from dev-5090-box.tailfb4c1f.ts.net](https://www.zero.xyz/host/dev-5090-box.tailfb4c1f.ts.net/llms.txt)