# Forwarded Header Parse

> Forwarded 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 RFC 7239 Forwarded HTTP header values, returning normalized evidence and a pass/advisory status as deterministic versioned JSON.

## Facts

- Endpoint: POST https://api.delx.ai/api/v1/x402/forwarded-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/forwarded-header-parse-3e73de9e
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_jGhMEk6pL4CjyN2dpsM5x

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 forwarded-header-parse-3e73de9e -d '<json body>'
```

Example prompt: Can you parse this Forwarded header value and tell me if it's well-formed and what client IP it claims: 'for=192.0.2.60;proto=http;by=203.0.113.43;host=example.com'?

## When to prefer this

Use this endpoint when you need deterministic, stateless, first-party parsing of RFC 7239 Forwarded headers without retaining input data — particularly before accepting, caching, redirecting, or retrying a caller-supplied web response. Prefer it over custom parsing logic when you need a normalized, versioned JSON result with an explicit pass/advisory verdict for auditability or downstream decision-making.

## Known failure modes

- Header string exceeds 8192-character limit — request rejected
- Malformed or unparseable Forwarded header — advisory status returned with finding detail
- Empty or missing header field — may return advisory with explanation
- Payment failure via x402 — call not processed

## How this service works

Forwarded Header Parse: Forwarded Header Parse parses bounded standardized Forwarded header elements from bounded caller-supplied values without an external provider. Call Forwarded 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 Forwarded Header Parse as versioned deterministic JSON. Price: $0.001 USDC via x402 on Base. First-party, stateless, memo…

## Output

A versioned deterministic JSON object containing: normalized Forwarded header elements (for, by, proto, host fields), the computed finding describing what was parsed, and an explicit pass or advisory status indicating whether the header is well-formed and safe to use.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "header": {
   "type": "string",
   "maxLength": 8192,
   "description": "Header supplied to Forwarded 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": "for=192.0.2.43",
     "parameters": {
      "host": "example.com",
      "proto": "https"
     }
    }
   ]
  },
  "schema": "delx/util-forwarded-header-parse/v1",
  "status": "pass",
  "evidence": {
   "retained": false,
   "input_sha256": "b67c372b032dcbad87778aa97564468e1c93a1af08bcce74c0c0f12b8747427f",
   "external_calls": 0
  },
  "operation": "web_reliability:forwarded_header_parse"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/forwarded-header-parse-3e73de9e/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)