# x402 Echo Service - Message Storage

> x402 Echo Service - Message Storage is a paid API for AI agents from x402-echo-service.fly.dev, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-15).

Stores a text message and returns a UUID handle that can be used to retrieve it later

## Facts

- Endpoint: POST https://x402-echo-service.fly.dev/api/echo
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x402-echo-service-fly-dev-fc7492e0
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_1lAdS2lIHSsmjwEyIwL-3

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 x402-echo-service-fly-dev-fc7492e0 -d '<json body>'
```

Example prompt: Store this message for me so I can retrieve it later: 'Meeting notes from Monday: discuss budget, review Q3 targets, confirm team offsite date.'

## When to prefer this

Use this endpoint when you need a simple, lightweight way to store a text message and get back a UUID handle for later retrieval, especially in x402 payment-enabled agentic workflows where a quick ephemeral key-value store is needed without setting up dedicated storage infrastructure.

## Known failure modes

- Missing X-PAYMENT header returns HTTP 402 with payment requirements including accepted assets and payTo address
- Empty or missing 'message' field in request body returns validation error
- Service unavailable on the fly.dev host returns 503 or connection error
- Payment amount insufficient returns 402 with maxAmountRequired details
- Malformed JSON body returns 400 bad request

## How this service works

Store a message and receive a UUID handle for retrieval

## Output

Returns a JSON object containing an 'id' field with a UUID string that serves as the handle to retrieve the stored message later.

## Example request

```json
{
 "message": "Test message for echo service: This is a sample message to verify the storage and retrieval functionality."
}
```

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "message"
 ],
 "properties": {
  "message": {
   "type": "string",
   "description": "A message to store"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "id": {
  "type": "string",
  "description": "UUID handle for retrieving the stored message"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x402-echo-service-fly-dev-fc7492e0/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402-echo-service.fly.dev](https://www.zero.xyz/host/x402-echo-service.fly.dev/llms.txt)