# AgentFeeds Echo Test Endpoint

> AgentFeeds Echo Test Endpoint is a paid API for AI agents from api.agentfeeds.jp, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-14).

Echoes a query string message back — an x402 payment integration test endpoint for developers validating paid API calls.

## Facts

- Endpoint: GET https://api.agentfeeds.jp/v1/sample/echo
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/agentfeeds-echo-test-endpoint-8e4a2d8d
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_ZgpRv0URqwU1DXIbVzBBY

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 agentfeeds-echo-test-endpoint-8e4a2d8d
```

Example prompt: Echo the message 'hello x402 test' through the AgentFeeds paid echo endpoint so I can confirm my x402 USDC micropayment integration is working end-to-end.

## When to prefer this

Use this endpoint when you need to verify that your x402 micropayment integration is correctly set up — it is the simplest possible paid API call (just an echo) and is purpose-built for E2E testing of payment flows. Not useful for production data retrieval.

## Known failure modes

- Missing 'msg' query param — endpoint may return empty or default response
- Payment failure — x402 handshake fails if USDC balance is insufficient (402 Payment Required)
- Message exceeds 200 characters — may be rejected or truncated
- Network timeout — endpoint unreachable
- Invalid x402 payment header — authentication/payment step fails

## How this service works

x402 payment E2E test endpoint (echoes query). Factual data only; not investment advice.

## Output

The endpoint returns the echoed text message that was sent as the 'msg' query parameter, confirming that the x402 payment was processed and the API call succeeded.

## 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"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "properties": {
      "msg": {
       "type": "string",
       "description": "text to echo (max 200 chars)"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "data": {
   "echo": "hello"
  },
  "kind": "factual_data",
  "product": "sample.echo"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/agentfeeds-echo-test-endpoint-8e4a2d8d/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.agentfeeds.jp](https://www.zero.xyz/host/api.agentfeeds.jp/llms.txt)