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RelayBox 24-Hour Callback Inbox
x402
RelayBox 24-Hour Callback Inbox is a paid API for AI agents from relaybox-phcqcexu4a-uc.a.run.app, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-27).
Provisions a durable, ordered 24-hour callback inbox with acknowledgment and replay support for reliable event delivery to AI agents or webhooks.
Price / call$0.01
Success—
StatusUnknown
How this service works
Buy a 24-hour durable callback inbox. Ordered events, acknowledgment and replay. See /llms.txt for required recovery headers.
Output
Returns a provisioned inbox resource including a unique callback URL, inbox ID, expiry time (24 hours from creation), and the required recovery/replay headers (as documented in /llms.txt) needed to retrieve ordered events and acknowledge receipt.
Example use cases
Agent fleet callback coordination
“I need a durable inbox that lasts 24 hours so my agent fleet can receive ordered webhook callbacks with acknowledgment — set one up for me now.”
Async API response collection
“Create a 24-hour callback inbox with replay support so I can reliably catch the async response from a long-running external API call, even if my listener drops momentarily.”
Temporary event buffer for integrations
“I'm wiring up a third-party integration and need a short-lived inbox that guarantees ordered delivery and lets me replay missed events — can you provision an inbox-24h for me?”
Technical details
Endpoint
POSThttps://relaybox-phcqcexu4a-uc.a.run.app/v1/inboxes?utm_source=zero.xyzWhen to prefer
Choose RelayBox when you need a durable, short-lived callback inbox with guaranteed ordered event delivery, acknowledgment, and replay capability — especially for AI agent workflows where the consumer may be intermittently offline and cannot afford to miss async callbacks. Prefer this over generic webhook receivers (e.g. webhook.site, requestbin) when ordered delivery and replay are critical requirements and a 24-hour window is sufficient.
Side effects
- Payment failure: USDC payment of $0.01 not confirmed, inbox not created
- Invalid plan: only 'inbox-24h' is accepted as a plan value — other values rejected
- Inbox expiry: inbox automatically expires after 24 hours, events no longer deliverable
- Missing recovery headers: events cannot be replayed without the correct headers returned at creation
- Service unavailability: Google Cloud Run cold-start or quota limits may cause transient 503 errors
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| plan | — |
Tags
x402
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