# x402.shizu.me FIFO Message Queue (Drop/Pop)

> x402.shizu.me FIFO Message Queue (Drop/Pop) is a paid API for AI agents from x402.shizu.me, paid per call via x402, $0.002/call, status unknown (last checked 2026-09-14).

Pops (dequeues) the oldest message from a named FIFO channel, enabling async coordination between agents that don't run simultaneously.

## Facts

- Endpoint: GET https://x402.shizu.me/drop
- Price: $0.002/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x402-shizu-me-fifo-message-queue-drop-pop-cccb9956
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_Q8N8UQWOxIiigW8SqpWGR

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-shizu-me-fifo-message-queue-drop-pop-cccb9956
```

Example prompt: Pop the next message from my 'order-results' channel — I'm the consumer agent and want to pick up whatever my producer left there.

## When to prefer this

Use this endpoint when a consumer agent needs to pick up data left by a producer agent that ran at a different time, and you need guaranteed FIFO ordering. Ideal for lightweight async agent-to-agent handoffs where both agents can't run concurrently. Prefer this over polling REST APIs or pub/sub when simplicity and FIFO semantics matter and message size is under 8KB.

## Known failure modes

- Channel is empty — no message available to pop, returns null or empty body
- Invalid or missing channel parameter — request rejected
- Message exceeds 8KB limit (relevant for enqueue side)
- Queue at 1000-message capacity — new enqueues may be rejected
- Payment not provided or insufficient — x402 payment required before message is delivered
- Network timeout or service unavailability

## How this service works

A FIFO mailbox for handing data between agents. POST {channel, message} enqueues JSON; GET ?channel= pops the oldest message. Use it to coordinate a producer agent and a consumer agent that never run at the same time. Message up to 8KB, up to 1000 queued per channel.

## Output

Returns the oldest enqueued JSON message on the specified channel (FIFO order), removing it from the queue. If no message is waiting, likely returns an empty or null response. Messages can be up to 8KB; up to 1000 messages can be queued per channel.

## Request schema (JSON Schema)

```json
{
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "properties": {
  "input": {
   "type": "object",
   "properties": {
    "method": {
     "const": "GET"
    },
    "queryParams": {
     "type": "object",
     "properties": {
      "channel": {
       "type": "string"
      }
     },
     "required": [
      "channel"
     ]
    }
   },
   "required": [
    "method"
   ]
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "depth": 1,
  "queued": true,
  "channel": "job-99"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x402-shizu-me-fifo-message-queue-drop-pop-cccb9956/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402.shizu.me](https://www.zero.xyz/host/x402.shizu.me/llms.txt)