# Cookie Domain Match

> Cookie Domain Match is a paid API for AI agents from api.delx.ai, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-14).

Evaluates whether a cookie's Domain attribute matches a request host according to RFC host-only and Domain cookie matching rules, returning a deterministic pass/advisory verdict.

## Facts

- Endpoint: POST https://api.delx.ai/api/v1/x402/cookie-domain-match
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/cookie-domain-match-5afa745c
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_P30ehuY_j8Y_dN5dn8-Vs

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 cookie-domain-match-5afa745c -d '<json body>'
```

Example prompt: Check whether the cookie domain '.example.com' matches the request host 'api.example.com' using RFC cookie domain matching rules — I need a deterministic pass or advisory verdict.

## When to prefer this

Use this endpoint when an agent needs a deterministic, RFC-compliant ruling on whether a cookie's Domain attribute (or host-only flag) applies to a given request host — particularly before accepting, caching, redirecting, or retrying a caller-supplied web response. Prefer this over custom logic when you need an auditable, versioned, stateless ruling that can be embedded in a pipeline without side effects or external lookups.

## Known failure modes

- Missing or empty request_host or cookie_domain fields returns a validation error
- Malformed hostnames (e.g. containing invalid characters) may produce an advisory/fail status
- Inputs exceeding 8192 characters are rejected
- Payment not included or insufficient USDC balance causes x402 payment failure
- Network or service unavailability returns an HTTP error

## How this service works

Cookie Domain Match: Cookie Domain Match evaluates host-only or Domain cookie matching for a request host from bounded caller-supplied values without an external provider. Call Cookie Domain Match before accepting, caching, redirecting, or retrying a caller-supplied web response. Returns normalized web evidence, the computed finding, and an explicit pass or advisory status for Cookie Domain Match as versioned deterministic JSON. Price: $0.001 USDC via x402 on Base. First-party, stateless, memor…

## Output

Returns versioned deterministic JSON containing: normalized web evidence (the sanitized input values), the computed cookie domain match finding (whether a host-only or Domain-attribute match succeeded), and an explicit pass or advisory status indicating whether the cookie is considered valid for the request host.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "request_host": {
   "type": "string",
   "maxLength": 8192,
   "description": "Request Host supplied to Cookie Domain Match; used only for this bounded calculation and processed in memory without retention."
  },
  "cookie_domain": {
   "type": "string",
   "maxLength": 8192,
   "description": "Cookie Domain supplied to Cookie Domain Match; used only for this bounded calculation and processed in memory without retention."
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "result": {
   "host": "api.example.com",
   "domain": "example.com",
   "matched": true
  },
  "schema": "delx/util-cookie-domain-match/v1",
  "status": "pass",
  "evidence": {
   "retained": false,
   "input_sha256": "a57277a00c736509ccdbdcbce69bc2a0db8554bde0c9b457722c07c13b3b210c",
   "external_calls": 0
  },
  "operation": "web_reliability:cookie_domain_match"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/cookie-domain-match-5afa745c/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.delx.ai](https://www.zero.xyz/host/api.delx.ai/llms.txt)