Terms of Service

Last updated: October 5, 2026

By using Mailsnail you agree to these terms. They're written to be short and unambiguous. If anything is unclear, email hello@mailsnail.dev and we'll clarify before you continue.

1. The service

Mailsnail is an MCP server and HTTP API that prints and mails physical letters and certified mail to US addresses via USPS on your behalf. You (or an AI agent acting under your account) compose the content; we handle production and delivery through our print supplier, Click2Mail.

2. Your account

  • You must be 18 or older to use the service.
  • You are responsible for everything sent through your account, including everything sent by AI agents you authorize.
  • Keep your API keys and sign-in credentials secret. If one leaks, email hello@mailsnail.dev immediately.

3. Acceptable content

You may not use the service to send mail that:

  • Threatens, harasses, defames, or impersonates another person.
  • Violates US federal, state, or postal law (this includes but isn't limited to USPS Domestic Mail Manual rules on non-mailable matter).
  • Contains content that infringes someone else's intellectual property.
  • Promotes fraud, illegal goods, or misleading commercial offers.
  • Targets recipients for unsolicited bulk mail without lawful basis.

We do not review the content of every piece before it is printed, and you are responsible for what you send. The recipient address must pass our print supplier's USPS address check, which is not a content check. We reserve the right to refuse or hold any piece that appears to violate this policy and to suspend accounts that abuse the service.

4. Payment, balance and auto-reload

  • Mail is paid for from a prepaid balance. You fund it on a Stripe-hosted checkout page. Stripe processes the payment and collects your card details; we never see or store your full card number. By default the checkout is a one-time payment: we do not save your card and do not charge it again. The balance can only be spent on Mailsnail postage and printing.
  • Current prices are on the pricing page. Sending a piece deducts its price from your balance. For letters, a preview shows the proof and the exact price before anything is charged, and the price shown is the price deducted. Checking an address, previewing a letter, and checking your balance or the status of a piece are free.
  • Instead of adding funds to your balance, you can pay for a single letter by card. That is a separate one-time Stripe payment of a price that includes the card processing fee, so it is a little higher than the price from a balance. We do not save the card or charge it again. For letters, the preview shows both prices.
  • Auto-reload is optional and is off unless you opt in. You opt in by asking your AI assistant for a funding link that saves your card; Stripe's checkout page then shows the terms, and you agree to them by paying. Once it is on, when your balance falls below a threshold (default $10), or is too low to cover a piece you are sending, we charge your saved card the reload amount (default $25, between $10 and $500). If one reload would not cover a piece, we charge a multiple of it, never more than $500 in one charge. The amounts are shown on Stripe's checkout page before you pay. Accounts that set up auto-reload before it became opt-in keep it until they turn it off.
  • If a reload charge is declined, auto-reload turns off until you add a working card, and a send that needed the reload does not go through.
  • You can turn auto-reload off at any time. Turning it off is free, stops automatic charges, and keeps your card on file. Ask your AI assistant to turn it off (the turn_off_auto_reload tool), email hello@mailsnail.dev, or, if you use the REST API, send PATCH /v1/billing/auto-reload with {"enabled": false}. On a team account, only an organization admin can do this.
  • If a piece fails before it is submitted for printing, its price is returned to your balance automatically. Unspent balance can be refunded to the original card on request: email hello@mailsnail.dev. Mail that has been submitted for printing cannot be recalled or refunded.
  • Prices may change. The price shown with a proof is the price you pay for that piece.

5. Delivery

Once a piece is handed to USPS, delivery is governed by USPS. We'll surface tracking and status when available, but we're not liable for delays or losses caused by the carrier.

6. Your content

You retain ownership of everything you send. You grant us a limited license to print, fold, address, and post each piece, and to share it with our print supplier for that purpose. How we keep and delete records is described in the privacy policy.

7. Service availability

We aim for high availability but make no uptime guarantee. We may perform maintenance that temporarily affects the service.

8. Liability

The service is provided “as is.” Our maximum aggregate liability for any claim is the amount you paid us in the 12 months before the claim. We aren't liable for indirect, incidental, or consequential damages.

9. Termination

You can close your account any time by emailing hello@mailsnail.dev. We can suspend or terminate accounts that violate these terms, with or without notice depending on severity.

10. Changes

We'll update this page when these terms change. Continuing to use the service after a change means you accept the new terms.

Contact

hello@mailsnail.dev