# Delx Commerce — X402 Response Header Shape Validator

> Delx Commerce — X402 Response Header Shape Validator is a paid API for AI agents from commerce.delx.ai, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-02).

Validates and parses an X402 payment response header to confirm it matches the expected shape/encoding, returning a verifiable pass/fail result with evidence.

## Facts

- Endpoint: POST https://commerce.delx.ai/api/v1/x402/x402-response-header-shape?utm_source=zero.xyz
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-02
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/delx-commerce-x402-response-header-shape-validator-5d2cd12f
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_H00d80fKS2dhC6NNqpLmj

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 delx-commerce-x402-response-header-shape-validator-5d2cd12f -d '<json body>'
```

Example prompt: Can you check whether this x402 response header is correctly shaped and passes validation: 'X-Payment-Response: eyJzY2hlbWEiOiJ4NDAyIn0='?

## When to prefer this

Use this endpoint when you need a lightweight, stateless, verifiable check that an X402 response header conforms to the expected shape and encoding before trusting or forwarding a payment confirmation. Prefer it over manual parsing when you need cryptographic evidence (SHA-256 of input) that the check was performed, or when operating in an agent pipeline that requires auditability and proof of non-retention of sensitive header data.

## Known failure modes

- Header string exceeds 8192 character limit — request rejected
- Malformed or non-x402 header — shape_valid returns false with status 'fail'
- Empty or missing header field — validation cannot proceed
- Network timeout or service unavailability — HTTP 5xx response
- Invalid payment / insufficient USDC balance — HTTP 402 returned before processing

## How this service works

Pay-per-result APIs for agents. No signup. Exact price. Verifiable delivery. USDC on Base + Solana via x402.

## Output

Returns a JSON object containing: a 'status' field ('pass' or 'fail'), a 'result' object with 'shape_valid' boolean and 'encoding' type (e.g. 'base64_json'), an 'operation' identifier, a 'schema' version string, and an 'evidence' block with SHA-256 hash of the input, a 'retained: false' flag confirming no data storage, and external_calls count (0).

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "header": {
   "type": "string",
   "maxLength": 8192,
   "description": "Header supplied to X402 Response Header Shape; used only for this bounded calculation and processed in memory without retention."
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "result": {
   "encoding": "base64_json",
   "shape_valid": true
  },
  "schema": "delx/util-x402-response-header-shape/v1",
  "status": "pass",
  "evidence": {
   "retained": false,
   "input_sha256": "568768ddc248cedc248ab1ccfdcc4bd01ee9005aa08eff63b5e7df553e7ff724",
   "external_calls": 0
  },
  "operation": "delivery_contract:x402_response_header_shape"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/delx-commerce-x402-response-header-shape-validator-5d2cd12f/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from commerce.delx.ai](https://www.zero.xyz/host/commerce.delx.ai/llms.txt)