PostalForm Postcards API

openapi: 3.2.0
info:
  title: PostalForm Projects Public Postcards API
  version: '2026-05-06'
  description: Public PostalForm Projects API for customer SDKs. Includes document uploads, quotes, mail orders, credits, API keys, and signed customer webhooks.
servers:
- url: https://projects.postalform.com
tags:
- name: Postcards
paths:
  /api/v1/postcards/quotes:
    post:
      summary: Quote a postcard mailpiece
      description: Postcards require a fully composed two-page PDF and a postcard_size of 4x6, 6x9, or 11x6. Postcards are first-class, color, double-sided mailpieces and do not support certified or registered mail.
      security:
      - bearerAuth: []
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/CreatePostcardQuoteRequest'
      responses:
        '200':
          description: Postcard quote.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Quote'
      operationId: createPostcardQuote
      tags:
      - Postcards
  /api/v1/postcards:
    post:
      summary: Create a test or live postcard order from a postcard quote
      security:
      - bearerAuth: []
      parameters:
      - name: Idempotency-Key
        in: header
        required: true
        schema:
          type: string
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/CreateLetterRequest'
      responses:
        '200':
          description: Idempotent replay.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Letter'
        '201':
          description: Created postcard order.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Letter'
      operationId: createPostcard
      tags:
      - Postcards
  /api/v1/postcards/{order_id}:
    get:
      summary: Retrieve a postcard order, timeline, tracking fields, and customer webhook…
      security:
      - bearerAuth: []
      parameters:
      - $ref: '#/components/parameters/OrderId'
      responses:
        '200':
          description: Postcard order detail.
          content:
            application/json:
              schema:
                allOf:
                - $ref: '#/components/schemas/Letter'
                - type: object
                  properties:
                    timeline:
                      type: array
                      items:
                        $ref: '#/components/schemas/MailOrderEvent'
                    webhook_events:
                      type: array
                      items:
                        $ref: '#/components/schemas/WebhookEvent'
      operationId: getPostcard
      tags:
      - Postcards
  /api/v1/postcards/{order_id}/document.pdf:
    get:
      summary: Preview or download the PDF for a postcard order
      description: Streams the prepared postcard PDF when available, otherwise the original uploaded PDF while preparation is pending. Documents follow the workspace document retention window.
      security:
      - bearerAuth: []
      parameters:
      - $ref: '#/components/parameters/OrderId'
      - name: version
        in: query
        required: false
        schema:
          type: string
          enum:
          - current
          - original
          - prepared
          default: current
        description: current returns the prepared PDF when available and otherwise the original upload.
      - name: disposition
        in: query
        required: false
        schema:
          type: string
          enum:
          - inline
          - attachment
          default: inline
        description: Use attachment to download instead of previewing inline.
      responses:
        '200':
          description: PDF bytes.
          content:
            application/pdf:
              schema:
                type: string
                format: binary
      operationId: getPostcardDocument
      tags:
      - Postcards
components:
  schemas:
    WebhookEvent:
      type: object
      properties:
        id:
          type: string
        workspaceId:
          type: string
        orderId:
          type: string
        eventType:
          $ref: '#/components/schemas/CustomerWebhookEventType'
        payload:
          $ref: '#/components/schemas/CustomerWebhookPayload'
        createdAt:
          type: string
          format: date-time
        deliveries:
          type: array
          items:
            $ref: '#/components/schemas/WebhookDeliveryAttempt'
    CustomerWebhookEventType:
      type: string
      description: Customer webhook event names emitted for fulfillment status changes. Replace `letter` with `postcard` for postcard mailpieces.
      enum:
      - postalform.letter.accepted
      - postalform.letter.in_transit
      - postalform.letter.delivered
      - postalform.letter.returned
      - postalform.letter.failed
      - postalform.letter.canceled
      - postalform.postcard.accepted
      - postalform.postcard.in_transit
      - postalform.postcard.delivered
      - postalform.postcard.returned
      - postalform.postcard.failed
      - postalform.postcard.canceled
      x-enumDescriptions:
        postalform.letter.accepted: Letter accepted for production or mailing after the order leaves PostalForm's preparation queue.
        postalform.letter.in_transit: Letter entered the mail stream. The payload may include or update `mailpiece.tracking_number` when tracking is available.
        postalform.letter.delivered: Letter reported delivered by the carrier or delivery network.
        postalform.letter.returned: Letter returned or otherwise marked undeliverable.
        postalform.letter.failed: Letter could not be produced or mailed. Inspect the order timeline and retry with a corrected request when appropriate.
        postalform.letter.canceled: Letter canceled before delivery completion.
        postalform.postcard.accepted: Postcard accepted for production or mailing after the order leaves PostalForm's preparation queue.
        postalform.postcard.in_transit: Postcard entered the mail stream. The payload may include or update `mailpiece.tracking_number` when tracking is available.
        postalform.postcard.delivered: Postcard reported delivered by the carrier or delivery network.
        postalform.postcard.returned: Postcard returned or otherwise marked undeliverable.
        postalform.postcard.failed: Postcard could not be produced or mailed. Inspect the order timeline and retry with a corrected request when appropriate.
        postalform.postcard.canceled: Postcard canceled before delivery completion.
    CustomerWebhookPayload:
      type: object
      description: JSON body POSTed to customer webhook endpoints.
      properties:
        id:
          type: string
          example: evt_123
        type:
          $ref: '#/components/schemas/CustomerWebhookEventType'
        data:
          type: object
          properties:
            object:
              $ref: '#/components/schemas/Letter'
        mailpiece:
          type: object
          properties:
            status:
              type: string
              nullable: true
            tracking_number:
              type: string
              nullable: true
            tracking_status:
              type: string
              nullable: true
    Quote:
      type: object
      properties:
        standalone_address_page:
          type: boolean
          description: Resolved standalone address page setting saved on this quote. Always false for postcards.
        quote_id:
          type: string
        mailpiece_type:
          type: string
          enum:
          - letter
          - postcard
        postcard_size:
          type:
          - string
          - 'null'
          enum:
          - 4x6
          - 6x9
          - 11x6
          - null
        price_cents:
          type: integer
        currency:
          type: string
          enum:
          - usd
        pricing_version:
          type: string
        certified_return_receipt:
          type: boolean
        return_receipt_format:
          type: string
          enum:
          - electronic
          - physical
        restricted_delivery:
          type: boolean
        err_delivery:
          type: string
          enum:
          - manual
          - email
        err_email:
          type:
          - string
          - 'null'
          format: email
        signature_required:
          type: boolean
        expires_at:
          type: string
          format: date-time
    MailOrderEvent:
      type: object
      description: Customer-facing order timeline event. Internal fulfillment identifiers are not exposed.
      properties:
        id:
          type: string
        event_type:
          type: string
        status_before:
          type: string
        status_after:
          type: string
        source:
          type: string
        created_at:
          type: string
          format: date-time
    CreateLetterRequest:
      type: object
      description: Create an order from a quote. Requires Idempotency-Key header. Sender is strongly recommended for all live mail and required for some destinations and mailpiece options.
      properties:
        quote_id:
          type: string
        recipient:
          $ref: '#/components/schemas/MailingAddress'
        sender:
          $ref: '#/components/schemas/MailingAddress'
        metadata:
          type: object
          description: Optional caller metadata stored on the order and surfaced in reads/webhook payloads.
          additionalProperties: true
      required:
      - quote_id
      - recipient
    MailOrderStatus:
      type: string
      enum:
      - queued
      - document_preparing
      - document_prepared
      - submitted
      - accepted
      - in_transit
      - delivered
      - returned
      - submission_pending
      - failed
      - canceled
      description: Order timeline status. `submission_pending` means the fulfillment submit job entered a physical-mail safety window where PostalForm cannot blindly retry without risking duplicate mail; it requires reconciliation if it remains the current order status.
    Mode:
      type: string
      enum:
      - test
      - live
    MailingAddress:
      type: object
      description: Flexible mailing address object. Pass countryCode, country_code, country, address_country, or addressCountry for international destinations; country defaults to US when omitted.
      additionalProperties: true
      properties:
        name:
          type: string
        company:
          type: string
        line1:
          type: string
          description: Also accepts street1, address_line1, or addressLine1.
        line2:
          type: string
          description: Also accepts street2, address_line2, or addressLine2.
        city:
          type: string
          description: Also accepts address_city or addressCity.
        state:
          type: string
          description: Also accepts province, provinceOrState, address_state, or addressState.
        postal_code:
          type: string
          description: Also accepts postalCode, postalOrZip, zip, address_zip, or addressZip.
        countryCode:
          type: string
          minLength: 2
          maxLength: 2
          default: US
          description: ISO 3166-1 alpha-2 country code. Defaults to US when omitted.
    WebhookDeliveryAttempt:
      type: object
      properties:
        id:
          type: string
        webhookEventId:
          type: string
        endpointId:
          type: string
        attemptNumber:
          type: integer
        status:
          type: string
          enum:
          - succeeded
          - failed
        httpStatus:
          type: integer
        responseBodySnippet:
          type: string
        attemptedAt:
          type: string
          format: date-time
        nextRetryAt:
          type: string
          format: date-time
    CreatePostcardQuoteRequest:
      type: object
      description: Postcard quote request. Postcards force first-class color double-sided mail and cannot use certified or registered mail.
      properties:
        document_id:
          type: string
        page_count:
          type: integer
          minimum: 1
          description: Optional explicit PDF page count. Postcard source PDFs should be fully composed.
        postcard_size:
          type: string
          enum:
          - 4x6
          - 6x9
          - 11x6
        destination_country_code:
          type: string
          minLength: 2
          maxLength: 2
          default: US
          description: ISO 3166-1 alpha-2 destination country code used for quote validation and pricing. Defaults to US.
        origin_country_code:
          type: string
          minLength: 2
          maxLength: 2
          default: US
          description: ISO 3166-1 alpha-2 sender/origin country code used for quote validation and pricing. Defaults to US.
      required:
      - document_id
      - postcard_size
    Letter:
      type: object
      properties:
        id:
          type: string
        object:
          type: string
          enum:
          - letter
          - postcard
        mailpiece_type:
          type: string
          enum:
          - letter
          - postcard
        postcard_size:
          type:
          - string
          - 'null'
          enum:
          - 4x6
          - 6x9
          - 11x6
          - null
        status:
          $ref: '#/components/schemas/MailOrderStatus'
        mode:
          $ref: '#/components/schemas/Mode'
        price_cents:
          type: integer
        currency:
          type: string
        funds_status:
          type: string
        billing_rail:
          type: string
        tracking_number:
          type: string
          nullable: true
          description: Carrier tracking number when available.
        tracking_url:
          type:
          - string
          - 'null'
          format: uri
          description: Direct USPS tracking URL when a tracking number is available. Manual ERR customers can use it to request their receipt from USPS.
        tracking_status:
          type: string
          nullable: true
          description: Normalized tracking status when available.
        return_receipt_format:
          type: string
          enum:
          - electronic
          - physical
        restricted_delivery:
          type: boolean
        err_delivery:
          type: string
          enum:
          - manual
          - email
        err_email:
          type:
          - string
          - 'null'
          format: email
        err_status:
          type: string
          enum:
          - manual
          - pending
          - sent
          - failed
          - expired
        err_delivered_at:
          type:
          - string
          - 'null'
          format: date-time
        err_retention_until:
          type:
          - string
          - 'null'
          format: date-time
          description: Last instant at which an acquired receipt remains retrievable. PostalForm's default ERR retention is three years.
        return_receipt_available:
          type: boolean
          description: Whether a stored electronic receipt can currently be downloaded.
        return_receipt_url:
          type:
          - string
          - 'null'
          description: Relative authenticated download URL when return_receipt_available is true.
        metadata:
          type: object
          additionalProperties: true
        created_at:
          type: string
          format: date-time
        updated_at:
          type: string
          format: date-time
        idempotent_replay:
          type: boolean
  parameters:
    OrderId:
      name: order_id
      in: path
      required: true
      schema:
        type: string
  securitySchemes:
    bearerAuth:
      type: http
      scheme: bearer