Mailbox.bot

What is Mailbox.bot?

Mailbox.bot is a postal mail API and MCP server that lets AI agents send physical mail. It provides two live workflows: outbound physical mail via API and inbound forwarded document context for reply loops. It is for developers and operators building AI agents that need to send letters, certified mail, postcards, and documents or process inbound postal mail context.

How to use Mailbox.bot?

Add the MCP server to your client config with a url of https://mailbox.bot/api/mcp and an Authorization header with a bearer token. Alternatively, use the REST API directly with POST /v1/mail and required headers. A sandbox mode with test keys (sk_agent_test_) is available for dry runs.

Key features of Mailbox.bot

• Outbound physical mail via API (PDF, DOCX, letters, certified)
• Inbound document context with OCR-backed reply loop
• Postal threads linking inbound and outbound events
• Certified mail, Priority, FedEx, UPS shipping
• Batch mail up to 10,000 pieces with volume discounts
• Sandbox with test keys, dry runs, lifecycle simulation

Use cases of Mailbox.bot

• An AI agent sends a certified letter to a customer with proof of delivery
• A workflow forwards scans from existing virtual mailboxes for agent review and reply
• An agent processes batch mailings of notices or invoices
• A human-in-the-loop flow pauses outbound mail for approval before printing
• Testing postal integration without real costs using sandbox keys

FAQ from Mailbox.bot

What is outbound mail in Mailbox.bot?

Submit a PDF, facility prints, stuffs, stamps, and mails it with photo proof. Classes include USPS First Class, Certified, and FedEx/UPS.

How does inbound forwarding work?

Operators forward scans, photos, PDFs, or virtual mailbox notices to private aliases on forward.mailbox.bot. Agents read context and draft linked replies using inbound_capture_id and postal_mail_thread_id.

Is a real mailing mailbox address available?

A mailbox.bot-issued street address with mailbox number for agents begins issuing August 31, 2026 for approved accounts. It is separate from the live forwarded inbound context.

What pricing does Mailbox.bot offer?

The inbound context + outbound mail plan is $0/month. A real mailing mailbox address is planned at $10/month. Outbound pricing starts at $1.00 for a 1-page First Class letter.

What billing safeguards are available?

The X-Max-Cost-Cents header limits cost per request, dry_run=true prevents actual charges, and daily spend caps can be set via the dashboard.