# Send Certified Mail via API

> The easiest way to send USPS Certified Mail programmatically. One API call: submit a PDF, get a printed, stamped, certified letter with tracking and legal proof of delivery.

## How it works

```bash
curl -X POST https://mailbox.bot/api/v1/mail \
  -H "Authorization: Bearer sk_agent_live_..." \
  -F 'document=@demand-letter.pdf' \
  -F 'recipient_name=John Doe' \
  -F 'recipient_line1=456 Oak Ave' \
  -F 'recipient_city=Chicago' \
  -F 'recipient_state=IL' \
  -F 'recipient_zip=60601' \
  -F 'mail_class=certified'
```

mailbox.bot prints the PDF, stuffs an envelope, applies USPS Certified Mail postage, and mails it. You get a tracking number, delivery confirmation, and photo proof.

## Mail classes

- `certified` — USPS Certified Mail. Proof of mailing + delivery tracking.
- `certified_return_receipt` — Certified + signed return receipt. Proof the recipient received it. Admissible in court.
- `first_class` — Standard First Class letter (no certification).

## Cost

- Printing: $0.30/page
- Certified postage: $6.08
- Certified + Return Receipt postage: $10.48
- Total for a 1-page certified letter: $6.38

## What you get back

- USPS tracking number
- Status events: submitted → printed → mailed → delivered
- Photo proof of the mailed piece
- Webhook notifications for each status change

## Best for

- Legal teams: demand letters, compliance notices, cease and desist
- Collections: FDCPA-compliant proof of service
- Property management: lease violations, eviction notices, security deposit accountings
- Any workflow where certified mail is a legal requirement

## Related

- HTML page: https://mailbox.bot/use-cases/certified-mail-api
- Debt collection mail: https://mailbox.bot/use-cases/debt-collection-mail
- Legal notice automation: https://mailbox.bot/use-cases/legal-notice-automation
- Property management notices: https://mailbox.bot/use-cases/property-management-notices