# ZenVault X.echo

> ZenVault X.echo is a paid API for AI agents from api.zenvault.eu, paid per call via x402, $0.005/call, status unknown (last checked 2026-10-02).

Echoes a submitted payload back as a created resource with a one-time management token, serving as a test or validation endpoint for the x402 micropayment protocol.

## Facts

- Endpoint: POST https://api.zenvault.eu/v1/x402/echo?utm_source=zero.xyz
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-02
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/zenvault-x-echo-364075a4
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_1zAMhIjq7pMRUQBNfzRMh

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 zenvault-x-echo-364075a4 -d '<json body>'
```

Example prompt: Send a test echo request to ZenVault's x402 endpoint with my payload and get back the echoed resource and management token so I can verify my micropayment integration is working.

## When to prefer this

Choose this endpoint when you need to test or validate an x402 micropayment integration specifically on the ZenVault platform, confirm round-trip payload integrity, or obtain a one-time management token as part of a paid API workflow. It is best suited for developer testing, integration smoke-testing, and verifying that x402 payment headers are correctly formed and accepted.

## Known failure modes

- Payment not included or malformed x402 header — results in 402 Payment Required
- Invalid or malformed request body — may return 400 Bad Request
- Management token is one-time use; reusing it will fail
- Service unavailability at api.zenvault.eu returns 5xx errors
- Insufficient USDC balance causes payment failure and request rejection

## How this service works

ZenVault X.echo

## Output

A JSON object containing the created (echoed) resource — mirroring the submitted payload — plus a one-time management token that can be used for subsequent resource management operations.

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/zenvault-x-echo-364075a4/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.zenvault.eu](https://www.zero.xyz/host/api.zenvault.eu/llms.txt)