# SiteCheck Regex Generator

> SiteCheck Regex Generator is a paid API for AI agents from api.sitecheck-api.workers.dev, paid per call via x402, $0.002/call, status unknown (last checked 2026-10-16).

Generates a tested regular expression pattern from example match/non-match strings and a plain-English description

## Facts

- Endpoint: POST https://api.sitecheck-api.workers.dev/api/regex/generate?utm_source=zero.xyz
- Price: $0.002/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-16
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/sitecheck-regex-generator-61d4406b
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_MSbwnXpfEcONKWtqb0LZR

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 sitecheck-regex-generator-61d4406b -d '<json body>'
```

Example prompt: Generate a regex pattern that matches strings like 'INV-2024-0042' and 'INV-1999-9999' but not 'INV-24-42' or 'INVOICE-2024-0042' — it should match invoice IDs with a 4-digit year and 4-digit sequence number.

## When to prefer this

Choose this endpoint when you need a tested regex generated from concrete examples rather than writing one by hand. It's especially useful when you can enumerate what should and shouldn't match but can't easily articulate the formal grammar. Prefer it over asking a general LLM for regex because the output is automatically back-tested against your examples and includes a pass/fail report.

## Known failure modes

- Invalid or contradictory match/non-match examples that cannot be reconciled into a single pattern
- Too many or too few examples (outside 1-10 match items)
- Examples exceed 300-character limit per string
- Description too vague for pattern generation
- Pattern generation may produce a pattern that overfits or underfits edge cases not covered by provided examples
- Payment failure returns 402 status

## How this service works

A regular expression from a description, with examples that must match and examples that must not. The pattern is returned only when every example passes when tested in the service (one retry with the failures). Patterns with nested quantifiers are refused to avoid catastrophic backtracking. Examples are up to 10 strings of 300 characters each.

## Output

Returns a JSON object containing: the generated regex pattern string, optional flags, a plain-English explanation of what the pattern matches, a test summary showing whether all provided match/non-match examples passed, counts of matches and non-matches tested, and a timestamp. A note reminds that the pattern was only verified against the provided examples.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "matches": {
   "type": "array",
   "description": "Strings the pattern must match (1-10 items, each max 300 characters)"
  },
  "nonMatches": {
   "type": "array",
   "description": "Strings the pattern must not match (0-10 items, each max 300 characters)"
  },
  "description": {
   "type": "string",
   "description": "What the pattern should match, in plain words (max 500 characters)"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "note": "Tested only against the examples you gave; it may still match or miss other inputs.",
  "flags": "",
  "tests": {
   "passed": true,
   "matches": 2,
   "nonMatches": 3
  },
  "pattern": "^\\d{5}$",
  "checkedAt": "2026-10-15T18:21:15.842Z",
  "explanation": "The pattern ^\\d{5}$ matches a string that starts with and ends with exactly 5 digits, ensuring a five-digit postal code."
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/sitecheck-regex-generator-61d4406b/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.sitecheck-api.workers.dev](https://www.zero.xyz/host/api.sitecheck-api.workers.dev/llms.txt)