# Saylor Innovations x402 WhoAmI Echo

> Saylor Innovations x402 WhoAmI Echo is a paid API for AI agents from saylorinnovations.com, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-12).

Echoes the caller's public IP, user agent, and x402 payment details the server received, for debugging x402 client integrations.

## Facts

- Endpoint: GET https://saylorinnovations.com/api/x402/whoami?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-12
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/saylor-innovations-x402-whoami-echo-94670645
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_lJ5RGR57NntfLdy-XsmaV

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 saylor-innovations-x402-whoami-echo-94670645
```

Example prompt: Can you hit the Saylor Innovations x402 whoami endpoint and tell me what IP address, user agent, and payment details the server actually received from my client?

## When to prefer this

Use this endpoint specifically when debugging an x402 payment client integration — it is the only endpoint that reflects back both network identity (IP, user agent) AND the x402 payment object the server actually parsed, making it ideal for verifying end-to-end x402 payment header transmission. Prefer it over general HTTP echo services when payment protocol correctness is what you need to verify.

## Known failure modes

- Payment validation failure if x402 payment header is malformed or missing — server may reject with 402
- Null IP or user agent if the server cannot determine those values from the request context
- Network timeout if the endpoint is temporarily unavailable
- Invalid payment amount or currency returns an error before echoing details

## How this service works

Echo your public IP, user agent and payment as the server saw them - for debugging an x402 client

## Output

A JSON object containing: the caller's public IP address (string or null), the user agent string (string or null), a payment object with the x402 payment details the server received, and a received_at ISO timestamp indicating when the request arrived.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET",
      "POST",
      "PUT",
      "PATCH",
      "DELETE",
      "HEAD"
     ],
     "type": "string"
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "json"
    },
    "example": {
     "type": "object",
     "required": [
      "ip",
      "payment",
      "received_at"
     ],
     "properties": {
      "ip": {
       "type": [
        "string",
        "null"
       ],
       "description": "IP address"
      },
      "payment": {
       "type": "object"
      },
      "user_agent": {
       "type": [
        "string",
        "null"
       ],
       "description": "User-agent the rules were evaluated for"
      },
      "received_at": {
       "type": "string",
       "description": "Received at (UTC unless a time zone is given)"
      }
     }
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/saylor-innovations-x402-whoami-echo-94670645/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from saylorinnovations.com](https://www.zero.xyz/host/saylorinnovations.com/llms.txt)