# Link Header Parse

> Link Header Parse is a paid API for AI agents from api.delx.ai, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-15).

Parses and validates Link header values, extracting targets and relation parameters with deterministic pass/advisory status.

## Facts

- Endpoint: POST https://api.delx.ai/api/v1/x402/link-header-parse
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/link-header-parse-6b27bc2e
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_ki8MTCn3uin-NWs40f9YS

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 link-header-parse-6b27bc2e -d '<json body>'
```

Example prompt: Can you parse this Link header for me and tell me if it's safe to follow — I got back '<https://example.com/page2>; rel="next", <https://example.com/>; rel="first"' from an HTTP response and need the targets and rel values extracted before I cache it.

## When to prefer this

Choose this endpoint when you need deterministic, stateless, security-conscious parsing of HTTP Link headers before acting on them — especially when accepting untrusted headers from external HTTP responses prior to caching, redirecting, following pagination, or retrying. Prefer over ad-hoc regex parsing because it returns explicit pass/advisory safety status and normalized output in versioned JSON, making it audit-friendly for agentic pipelines.

## Known failure modes

- Header string exceeds 8192 character limit — rejected with bounds error
- Malformed or unparseable Link header syntax — returns advisory status with finding detail
- Empty header value — may return pass with empty targets
- Header contains ambiguous or conflicting relation parameters — advisory status returned
- Payment failure via x402 protocol — request rejected before processing

## How this service works

Link Header Parse: Link Header Parse parses bounded Link header targets and relation parameters from bounded caller-supplied values without an external provider. Call Link Header Parse 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 Link Header Parse as versioned deterministic JSON. Price: $0.001 USDC via x402 on Base. First-party, stateless, memory-only executi…

## Output

Returns versioned deterministic JSON containing the normalized link targets, extracted relation parameters, computed finding details, and an explicit pass or advisory status indicating whether the parsed header is safe to accept, cache, redirect from, or retry against.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "header": {
   "type": "string",
   "maxLength": 8192,
   "description": "Header supplied to Link Header Parse; used only for this bounded calculation and processed in memory without retention."
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "result": {
   "count": 1,
   "entries": [
    {
     "value": "https://api.example.com/items?page=2",
     "parameters": {
      "rel": "next"
     }
    }
   ]
  },
  "schema": "delx/util-link-header-parse/v1",
  "status": "pass",
  "evidence": {
   "retained": false,
   "input_sha256": "c29e9d075fe214f8f36932c4673fa5d7a8d63984c8a0ca8a21112ef48942249c",
   "external_calls": 0
  },
  "operation": "web_reliability:link_header_parse"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/link-header-parse-6b27bc2e/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)