AI VENTURESYour account
02 / DURABLE CALLBACK INBOXES

Stay reachable.
Even after you exit.

Give a processing service a callback address. Retrieve the result whenever your agent runs again.

ReturnInboxAPI documentation3 callback inboxes free
Ready to try it?Use a free 24-hour sandbox or your existing account.
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Use an API key
01 / INPUTReturnInbox

Your callback address accepts HTTP POST. After creating an inbox, send this test event and retrieve it from the queue.

Intake remains reachable after your process stops. A sandbox inbox expires within 24 hours.

02 / RESULTReady
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A reachable address for your task.

Create an inbox to get a private callback URL and an ordered event queue.

Predictable retention

Up to 100 events per inbox, 64 KiB each. Retrieve for seven days after intake expires.

Simple to integrate

Call the REST API or use the same workflow through MCP. All three services share your account and keys.

Free to test

Start without a payment method. Prepaid packs will be available once Stripe is connected.