# Allow Header Normalize

> Allow Header Normalize 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).

Normalizes and sorts HTTP Allow header method values into a canonical, deterministic form for validation and analysis.

## Facts

- Endpoint: POST https://api.delx.ai/api/v1/x402/allow-header-normalize
- 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/allow-header-normalize-74f4fd3b
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_eKacqx0DK5NJSKFTpkjuy

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 allow-header-normalize-74f4fd3b -d '<json body>'
```

Example prompt: Can you normalize this Allow header value for me — 'GET, POST, OPTIONS, DELETE, PUT' — so I know exactly what methods are listed in canonical sorted order before I cache the response?

## When to prefer this

Choose this endpoint when you need a stateless, deterministic, versioned normalization of an HTTP Allow header before caching, redirecting, retrying, or programmatically inspecting a web response. Ideal for agents that need consistent, canonical representation of server-advertised methods without building custom parsing logic.

## Known failure modes

- Malformed or empty header string returns advisory/fail status with finding detail
- Header exceeding 8192 character limit rejected
- Non-HTTP-method tokens in header may trigger advisory status
- Payment failure or insufficient USDC balance blocks request

## How this service works

Allow Header Normalize: Allow Header Normalize normalizes and sorts methods advertised by an Allow header from bounded caller-supplied values without an external provider. Call Allow Header Normalize 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 Allow Header Normalize as versioned deterministic JSON. Price: $0.001 USDC via x402 on Base. First-party, stateless,…

## Output

Returns a versioned deterministic JSON object containing the normalized and sorted list of HTTP methods from the Allow header, the computed validation finding, and an explicit pass or advisory status indicating whether the header is well-formed.

## Request schema (JSON Schema)

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

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "result": {
   "methods": [
    "GET",
    "OPTIONS",
    "POST"
   ],
   "normalized": "GET, OPTIONS, POST"
  },
  "schema": "delx/util-allow-header-normalize/v1",
  "status": "pass",
  "evidence": {
   "retained": false,
   "input_sha256": "0ecd36e96bbca98170b9eedc601e2bf858ebd547ce42de08db555b94ebabf822",
   "external_calls": 0
  },
  "operation": "web_reliability:allow_header_normalize"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/allow-header-normalize-74f4fd3b/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)