---
title: "Callback Inbox for Serverless Agents ($0.003/call)"
method: POST
path: "/webhook"
tags: ["webhook", "callback", "inbox", "async", "http", "agent", "serverless", "callback-url", "receive-webhooks"]
---

# Callback Inbox for Serverless Agents ($0.003/call)

`POST /webhook`

## Request

- Base URL: `https://x402.shizu.me`
- URL: `https://x402.shizu.me/webhook`
- Auth: none declared

Give an agent with no server a public URL that catches callbacks while it isn't running. POST {ttl?} mints a capture URL; any external service can POST JSON to it free; GET ?token= drains what arrived. Receive OAuth callbacks, payment notifications, job-completion pings, or another service's async results — without hosting, ngrok, or staying alive to listen.

Paid endpoint: $0.003 per call via the x402 protocol (USDC on Base). An unpaid request returns 402 with payment requirements in the PAYMENT-REQUIRED response header; attach payment and retry.

## Response `200`

Paid result (JSON)

## Other responses

- `402`: Payment required — x402 requirements in the PAYMENT-REQUIRED response header

---

[API](https://skmtc.dev/shizu/apis/scrape402.md) · [All operations](https://skmtc.dev/shizu/apis/scrape402/llms.txt) · [OpenAPI document](https://skmtc.dev/shizu/apis/scrape402/revisions/0852d74798b8?raw)