# WWW-Authenticate Header Parser

> WWW-Authenticate Header Parser 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 normalizes the WWW-Authenticate HTTP challenge header, extracting the authentication scheme and parameters for validation or downstream use.

## Facts

- Endpoint: POST https://api.delx.ai/api/v1/x402/www-authenticate-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/www-authenticate-header-parser-a83fdbbf
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_SUAGkIE2TCvjntwBsMS6v

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 www-authenticate-header-parser-a83fdbbf -d '<json body>'
```

Example prompt: Parse this WWW-Authenticate header for me and tell me what auth scheme and parameters it contains: 'Bearer realm="https://auth.example.com", error="invalid_token", error_description="The token is expired"'

## When to prefer this

Use this endpoint when your agent needs to programmatically parse, validate, or normalize a WWW-Authenticate header from an HTTP 401 or 407 response before deciding how to authenticate, cache, redirect, or retry. It is especially useful when handling untrusted or caller-supplied headers where you need a deterministic, in-memory, no-retention parse without building custom parser logic. Prefer this over manual string parsing when you need a structured, versioned JSON output with an explicit pass/advisory status.

## Known failure modes

- Empty or missing header field returns an advisory/fail status
- Malformed or unbounded header string may return parsing errors or advisory status
- Header exceeding 8192 character limit is rejected
- Completely unparseable input returns an advisory status rather than a hard error
- Payment failure (x402) prevents the call from being processed

## How this service works

Www Authenticate Parse: Www Authenticate Parse parses an authentication challenge scheme and bounded parameters from bounded caller-supplied values without an external provider. Call Www Authenticate 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 Www Authenticate Parse as versioned deterministic JSON. Price: $0.001 USDC via x402 on Base. First-party, stat…

## Output

Returns versioned deterministic JSON containing: the normalized WWW-Authenticate header evidence, the extracted authentication scheme (e.g. Bearer, Basic, Digest), parsed bounded parameters (e.g. realm, error, nonce, qop), and an explicit pass or advisory status indicating whether the header is well-formed and safe to process.

## Request schema (JSON Schema)

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

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "result": {
   "value": "bearer realm=api, error=invalid_token",
   "parameters": {}
  },
  "schema": "delx/util-www-authenticate-parse/v1",
  "status": "pass",
  "evidence": {
   "retained": false,
   "input_sha256": "4214e8b22b696222b9f2658c1f35c91515b02b4e02228ba03d6c3d0f684fac3e",
   "external_calls": 0
  },
  "operation": "web_reliability:www_authenticate_parse"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/www-authenticate-header-parser-a83fdbbf/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)