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PostalForm MPP Orders
mailprintlettersphysicalpostalweb
PostalForm MPP Orders is a paid API for AI agents from PostalForm at postalform.com, paid per call via MPP, $3.4/call (dynamic — varies by input), status unknown (last checked 2026-10-11).
Create or reuse an MPP machine order to print and mail a physical letter, postcard, or form to a recipient via postal service.
Price / call$3.4varies by input
Success—
StatusUnknown
How this service works
Unauthenticated calls return 402 Payment Required with WWW-Authenticate: Payment challenges. Retry the exact same body with Authorization: Payment after settlement.
Output
Returns a UUID order_id, payment status (is_paid, payment_status), mailpiece type (letter or postcard), postcard size if applicable, current fulfillment step, price in USD, machine payment details including protocol (x402/mpp), network, recipient wallet, and settlement reference, plus a campaign_url for bulk orders.
Example use cases
Example prompt
“Use PostalForm to mail a physical letter to John Smith at 123 Main St, Springfield IL 62701 — the sender is Acme Corp at 456 Oak Ave, Chicago IL 60601 — and use this PDF I have for the content.”
Technical details
Endpoint
POSThttps://postalform.com/api/machine/mpp/orders?utm_source=zero.xyzWhen to prefer
Use this endpoint when an AI agent needs to physically mail a document, letter, postcard, or form to a real postal address — especially for single-recipient or bulk campaigns using PDF, text, or HTML templates. Prefer over alternatives when payment is handled via x402/MPP crypto payment protocols and physical delivery is required rather than digital communication.
Side effects
- 402 Payment Required on unauthenticated call — must retry with Authorization: Payment header after settlement
- Invalid or missing required fields (recipient_name, sender/recipient address, content) returns 422 validation error
- PDF or HTML content malformed or too large returns content error
- Conflicting oneOf schema branches (e.g. both bulk and single-recipient fields) causes schema validation failure
- Address ID not found in account returns 404 or validation error
- Bulk template mode mismatch (text mode but no template_text provided) returns validation error
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| — | ||
| bulk | object | |
| form | object | Nested single-mailpiece workflow form payload. Discover available forms with GET /api/machine/forms, fetch the selected schema with GET /api/machine/forms/{slug}/schema, then send this form object instead of pdf or letter. Statutory workflows requiring coordinated service on multiple recipients are intentionally excluded. |
| color | boolean | Defaults to false. |
| format | string | Optional shorthand for letter.format when letter is provided. Defaults to text. |
| letter | — | Letter content for PostalForm to render server-side into a PDF. Provide exactly one of pdf, form, or letter. |
| certified | boolean | Proof-mail add-on. Uses USPS Certified Mail for US destinations, Canada Post Registered Mail through PostGrid for Canadian destinations, and PinGen registered mail for supported European destinations. Defaults to false. |
| err_email | string | Optional destination for err_delivery=email. Defaults to buyer_email when omitted. Not valid for physical PS Form 3811. |
| file_name | string | Optional display file name. |
| buyer_namerequired | string | Buyer / wallet owner display name. |
| mail_class | string | Mail service level. Defaults to standard. |
| request_idrequired | string | Client-generated idempotency key for one logical mailing. Reuse the same value on payment retries, and generate a fresh UUID for a legitimate second order even if the payload is identical. |
| buyer_emailrequired | string | Required for Stripe receipt delivery. |
| sender_namerequired | string | |
| double_sided | boolean | Defaults to true. |
| err_delivery | string | Defaults to manual USPS retrieval. Email makes PostalForm acquire and email the electronic receipt when available. |
| postcard_size | string | Required when mailpiece_type is postcard. The uploaded PDF must match the exact 2-page bleed template for that size. See /postcard-pdf-guidelines. |
| mailpiece_type | string | Optional mailpiece type. Defaults to letter. Set to postcard only when pdf is a fully composed postcard PDF that follows the published postcard layout guide. Nested workflow form and letter payloads are letter-only. |
| recipient_name | string | |
| sender_address_id | string | Loqate Address id. The leading segment carries the country, for example US|... or CA|.... The country must be one of US, CA, AT, BE, CH, DE, ES, FR, GB, IN, LU, NL. Required for sender Address mode. |
| signature_required | boolean | Request USPS signature on delivery. Defaults to false. Forced false for postcards or when mail_class is standard. |
| restricted_delivery | boolean | Requests USPS Restricted Delivery for addressee-only delivery. Requires certified_return_receipt=true. |
| sender_address_text | string | Human-readable address text for sender Address mode. |
| sender_address_type | string | Address strategy for the sender. Omit to default to Address when manual fields are absent. |
| recipient_address_id | string | Loqate Address id. The leading segment carries the country, for example US|... or CA|.... The country must be one of US, CA, AT, BE, CH, DE, ES, FR, GB, IN, LU, NL. Required for recipient Address mode. |
| return_receipt_format | string | Electronic selects the signed USPS PDF. Physical selects the mailed PS Form 3811 green card. Requires certified_return_receipt=true. |
| sender_address_manual | object | Manual sender address. Required for sender Manual mode. |
| recipient_address_text | string | Human-readable address text for recipient Address mode. |
| recipient_address_type | string | Address strategy for the recipient. Omit to default to Address when manual fields are absent. |
| certified_return_receipt | boolean | Return Receipt add-on for US Certified Mail. Defaults to the electronic format. Ignored for Canada Post Registered Mail and PinGen registered-mail destinations where receipt/confirmation is part of the registered service rather than a separate add-on. |
| recipient_address_manual | object | Manual recipient address. Required for recipient Manual mode. |
Output
Schema · Response
| Field | Type | Description |
|---|---|---|
| x402 | object | |
| statusrequired | string | |
| is_paidrequired | boolean | |
| currencyrequired | — | |
| order_idrequired | string | Canonical server order id. This may differ from request_id when PostalForm reuses an existing unpaid draft. |
| certified | boolean | |
| err_email | — | |
| price_usdrequired | — | |
| err_status | string | |
| page_count | — | |
| status_url | string | Poll this same order after either payment path. |
| next_action | string | |
| campaign_url | — | Bulk campaign dashboard route for mailing_campaign orders. Null for single-recipient orders. |
| checkout_url | — | Signed hosted-checkout fallback for this exact prepared PDF, letter, form, postcard or ordinary bulk order. Give this to the buyer when no compatible wallet is available. GET only reviews; continuing selects hosted payment. Null when payment has started or the order is closed. Poll status_url for a fresh link. |
| current_steprequired | — | |
| err_delivery | string | |
| tracking_url | — | |
| postcard_sizerequired | — | |
| mailpiece_typerequired | string | |
| payment_statusrequired | string | |
| machine_paymentrequired | object | |
| payment_channelrequired | — | |
| payment_options | array | |
| tracking_number | — | |
| err_delivered_at | — | |
| payment_intent_idrequired | — | |
| usps_tracking_url | — | |
| restricted_delivery | boolean | |
| return_receipt_format | string | |
| err_document_available | boolean | |
| postcard_guidelines_urlrequired | — | Canonical postcard PDF formatting guide. Present for postcard responses and null for letter responses. |
| certified_return_receipt | boolean |
Tags
mailprintlettersphysicalpostalweb
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