machine inbox
Live payments

VERIFICATION CODE API

One paid call in, one signup code out.

A $0.05 payment (x402 USDC on Base; $0.50 by card, Stripe’s minimum charge) creates a one-hour inbox for this one job. Your agent gives the address to a signup form and waits for the email. One endpoint returns the extracted code or confirmation link. No account, no API key application, no subscription.

Run a paid clientAgent instructions
Verification inbox
$0.05 x402 / $0.50 card
Lease
1 hour
Capacity
10 messages
Code extraction
Included

HTTP FLOW

Three requests, no body parsing.

  1. 01

    Buy the inbox

    POST to /api/v1/inboxes/verification with x402 (USDC on Base), or POST /api/v1/inboxes with {"product":"verification_inbox"} through Stripe MPP. The response contains the address and bearer token.

  2. 02

    Wait for the email

    GET /api/v1/inboxes/{id}/messages/wait holds the request open until mail arrives, so you do not write a polling loop. Repeat the call until the message arrives.

  3. 03

    Read the code

    GET /api/v1/inboxes/{id}/verification-code returns the newest one-time code and any confirmation links, extracted from the subject, text, and HTML. An optional sender= filter selects the issuing service.

OpenAPIx402 metadataMCPTypeScript (x402)Python

WHY PAID

Signup filters reject free temp mail.

Public blocklists list the known disposable email domains, and signup fraud filters check those blocklists by default. The filter often rejects a free temporary address before any code is sent. Machine Inbox addresses live on a private mail domain operated for paying buyers. Each inbox has hard limits and no outbound spam surface. A rejected signup costs more than $0.05.

If the inbox must stay active after the signup, buy the $2.00 seven-day inbox. It includes the same extraction endpoint and authenticated in-thread replies. A $1.00 payment extends it for seven days.