# Would Pay Again – Book Sponsor Slot 4

> Would Pay Again – Book Sponsor Slot 4 is a paid API for AI agents from wouldpayagain.com, paid per call via x402, $1.75/call, status unknown (last checked 2026-10-10).

Books an advertisement sponsorship slot (slot #4) in the Would Pay Again newsletter about the x402 machine-payments economy, paid via USDC on Base.

## Facts

- Endpoint: POST https://wouldpayagain.com/api/ads/book/sponsor-4?utm_source=zero.xyz
- Price: $1.75/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-10
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/would-pay-again-book-sponsor-slot-4-11cef4db
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_FMhbbDcWdTGPtXg1I0XxE

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 would-pay-again-book-sponsor-slot-4-11cef4db -d '<json body>'
```

Example prompt: Book sponsorship slot 4 in the Would Pay Again newsletter — I want to advertise my x402-compatible product to their machine-payments audience, and I'm happy to pay in USDC on Base.

## When to prefer this

Use this endpoint when you want to purchase advertising slot #4 specifically in the Would Pay Again newsletter and can pay in USDC on Base via the x402 protocol. This is the right choice for reaching an audience of developers, agents, and enthusiasts focused on machine-to-machine payments and the x402 economy. Choose this over generic ad networks when your target audience is specifically the crypto/x402/autonomous-payments community.

## Known failure modes

- Payment failure if Base wallet has insufficient USDC balance
- Slot already booked — slot 4 may be unavailable for the requested period
- Request body missing required fields (type, method, bodyType, body) returns validation error
- Blockchain settlement delay causing timeout before tx confirmation
- API returns non-200 if the x402 payment header is malformed or missing

## How this service works

A newsletter about the x402 machine-payments economy, sold over x402 itself. USDC on Base.

## Output

Returns a JSON object confirming the booking with fields: ok (boolean success), status (e.g. 'pending_review'), confirmed (boolean), booking_id (integer), tearsheet URL (link to booking details page), and settlement_tx (Base blockchain transaction hash of the USDC payment).

## 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",
    "bodyType",
    "body"
   ],
   "properties": {
    "body": {
     "type": "object"
    },
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "POST",
      "PUT",
      "PATCH"
     ],
     "type": "string"
    },
    "bodyType": {
     "enum": [
      "json",
      "form-data",
      "text"
     ],
     "type": "string"
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {}
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "ok": true,
  "status": "pending_review",
  "confirmed": true,
  "tearsheet": "https://wouldpayagain.com/api/ads/booking/6",
  "booking_id": 6,
  "settlement_tx": "0x…"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/would-pay-again-book-sponsor-slot-4-11cef4db/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from wouldpayagain.com](https://www.zero.xyz/host/wouldpayagain.com/llms.txt)