> ## Documentation Index > Fetch the complete documentation index at: https://docs.paperjoy.co/llms.txt > Use this file to discover all available pages before exploring further. # Update a draft > Changes only the draft fields you send. `null` clears a field, and `address` and `recipient` are replaced as a whole. A postcard that is no longer a draft can't be changed (`409`). Fields that aren't listed, such as `status`, return `422`. Requires the `postcards:write` ability. ## OpenAPI ````yaml /en/openapi.yaml patch /api/postcards/{id} openapi: 3.1.0 info: title: Paperjoy API version: '2026-10-19' description: >- Create, preview, and track real handwritten postcards. The API key decides whether a request runs in test or live mode. termsOfService: https://paperjoy.co/regulamin license: name: Proprietary url: https://paperjoy.co/regulamin servers: - url: https://paperjoy.co security: - bearerAuth: [] tags: - name: Account description: The authenticated account and its credit balance. - name: Postcards description: Create, preview, list, and retrieve postcards. - name: Signatures description: Custom handwritten signatures available to your organization. paths: /api/postcards/{id}: patch: tags: - Postcards summary: Update a draft description: >- Changes only the draft fields you send. `null` clears a field, and `address` and `recipient` are replaced as a whole. A postcard that is no longer a draft can't be changed (`409`). Fields that aren't listed, such as `status`, return `422`. Requires the `postcards:write` ability. operationId: updateDraftPostcard parameters: - $ref: '#/components/parameters/PostcardId' requestBody: required: true content: application/json: schema: $ref: '#/components/schemas/UpdateDraftPostcardRequest' example: content: |- Dear Anna, thank you for your first order! See you soon. responses: '200': description: The updated draft. content: application/json: schema: $ref: '#/components/schemas/PostcardResponse' '401': $ref: '#/components/responses/Unauthorized' '403': $ref: '#/components/responses/Forbidden' '404': $ref: '#/components/responses/NotFound' '409': $ref: '#/components/responses/NotDraft' '422': $ref: '#/components/responses/ValidationError' components: parameters: PostcardId: name: id in: path required: true description: The postcard ID. schema: type: string examples: - pc_MXP7a4Ni0c schemas: UpdateDraftPostcardRequest: type: object additionalProperties: false description: Send only the fields you want to change. `null` clears a field. properties: address: oneOf: - $ref: '#/components/schemas/Address' - type: 'null' recipient: oneOf: - $ref: '#/components/schemas/Recipient' - type: 'null' content: type: - string - 'null' maxLength: 300 signature: $ref: '#/components/schemas/TypedSignature' signature_id: $ref: '#/components/schemas/SignatureIdInput' font_id: oneOf: - $ref: '#/components/schemas/FontId' - type: 'null' mistake: $ref: '#/components/schemas/Mistake' PostcardResponse: type: object required: - data properties: data: $ref: '#/components/schemas/Postcard' Address: type: object required: - line_1 - postal_code - country - city properties: line_1: type: string maxLength: 255 description: Street and building number. examples: - ul. Marszałkowska 10 line_2: type: - string - 'null' maxLength: 255 description: Apartment, floor, or other detail. examples: - m. 4 postal_code: type: string pattern: ^\d{2}-\d{3}$ examples: - 00-001 country: type: string enum: - PL city: type: string maxLength: 255 examples: - Warszawa Recipient: type: object description: Send `first_name`, `company_name`, or both. properties: prefix: type: - string - 'null' maxLength: 30 examples: - Pani first_name: type: - string - 'null' maxLength: 255 last_name: type: - string - 'null' maxLength: 255 company_name: type: - string - 'null' maxLength: 255 TypedSignature: type: - string - 'null' maxLength: 50 description: >- A sign-off written on one line at the bottom of the card. Do not send together with `signature_id`. SignatureIdInput: type: - string - 'null' description: >- An active custom signature ID from `GET /api/signatures`. Requires a plan with custom signatures. Do not send together with `signature`. examples: - sig_ZeXOkSQjTp FontId: type: string enum: - font-1 - font-2 description: >- `font-1` is clear, rounded handwriting. `font-2` is a faster, joined-up cursive. Mistake: type: boolean default: false description: >- Cross out one word and write it again, like a real person would. The same message always gets the same correction. Postcard: type: object required: - id - test_mode - recipient - signature - signature_id - mistake - status - submitted_at - sent_at - created_at - updated_at properties: id: type: string examples: - pc_MXP7a4Ni0c test_mode: type: boolean description: >- `true` for a test postcard. Test postcards are free and are never written or mailed. address: description: The delivery address. Can be `null` only in a draft. oneOf: - $ref: '#/components/schemas/Address' - type: 'null' recipient: oneOf: - $ref: '#/components/schemas/Recipient' - type: 'null' content: type: - string - 'null' maxLength: 300 description: The message. Can be `null` only in a draft. signature: type: - string - 'null' maxLength: 50 description: >- The typed signature, or `null` when the postcard uses a custom signature. signature_id: type: - string - 'null' description: The custom signature used on the postcard, or `null`. examples: - sig_ZeXOkSQjTp font_id: description: The handwriting. Can be `null` only in a draft. oneOf: - $ref: '#/components/schemas/FontId' - type: 'null' mistake: type: boolean description: >- Whether one word is crossed out and rewritten to look naturally handwritten. status: $ref: '#/components/schemas/PostcardStatus' submitted_at: type: - string - 'null' format: date-time description: When the postcard was ordered. `null` while it's a draft. sent_at: type: - string - 'null' format: date-time description: When the postcard was mailed. `null` until the status is `sent`. created_at: type: - string - 'null' format: date-time updated_at: type: - string - 'null' format: date-time Error: type: object required: - message properties: message: type: string ValidationError: type: object required: - message - errors properties: message: type: string errors: type: object additionalProperties: type: array items: type: string PostcardStatus: type: string description: >- Where the postcard is in production. Treat unknown values as "in progress". enum: - draft - new - queued - rejected - pair_claimed - in_progress - pair_completed - sent responses: Unauthorized: description: The API key is missing, invalid, revoked, or expired. content: application/json: schema: $ref: '#/components/schemas/Error' example: message: Unauthenticated. Forbidden: description: >- The API key lacks the required ability, or the resource belongs to someone else. content: application/json: schema: $ref: '#/components/schemas/Error' example: message: This action is unauthorized. NotFound: description: The resource does not exist or belongs to the other mode. content: application/json: schema: $ref: '#/components/schemas/Error' example: message: Not found. NotDraft: description: >- The postcard is no longer a draft, or the `Idempotency-Key` was used with a different request. content: application/json: schema: $ref: '#/components/schemas/Error' example: message: >- Postcard pc_MXP7a4Ni0c has already been submitted (status: new). Only drafts can be changed, submitted, or deleted. ValidationError: description: >- A field is invalid, the text does not fit on the card or envelope, or the `Idempotency-Key` is longer than 255 characters. content: application/json: schema: anyOf: - $ref: '#/components/schemas/ValidationError' - $ref: '#/components/schemas/Error' examples: field: summary: Invalid field value: message: The selected font id is invalid. errors: font_id: - The selected font id is invalid. card_fit: summary: Message does not fit on the card value: message: >- The content does not fit on the postcard. Shorten it or remove blank lines. errors: content: - >- The content does not fit on the postcard. Shorten it or remove blank lines. envelope_fit: summary: Address does not fit on the envelope value: message: The sender or recipient address does not fit on the envelope. errors: address: - >- The sender or recipient address does not fit on the envelope. draft_limit: summary: Too many open drafts value: message: >- You already have 100 open drafts. Submit or delete some of them before saving another draft. errors: draft: - >- You already have 100 open drafts. Submit or delete some of them before saving another draft. signature_unavailable: summary: Custom signature unavailable value: message: >- The selected signature is unavailable or is not active for your plan. errors: signature_id: - >- The selected signature is unavailable or is not active for your plan. securitySchemes: bearerAuth: type: http scheme: bearer description: >- A Paperjoy API key. Keys starting with `pj_test_` use test mode; keys starting with `pj_live_` use live mode. ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.