> ## Documentation Index > Fetch the complete documentation index at: https://sendmux.ai/docs/llms.txt > Use this file to discover all available pages before exploring further. # Create a saved draft ## OpenAPI ````yaml /openapi-app.json post /mailbox/drafts openapi: 3.1.0 info: description: Programmatic access to your Sendmux email infrastructure. title: Sendmux API version: 1.0.0 servers: - description: API v1 url: https://app.sendmux.ai/api/v1 security: - bearerAuth: [] - oauth2: [] paths: /mailbox/drafts: post: tags: - Mailbox API summary: Create a saved draft operationId: mailboxCreateDraft parameters: - description: Reuse this key when retrying the same create request. in: header name: Idempotency-Key required: false schema: description: Reuse this key when retrying the same create request. maxLength: 255 type: string - description: >- Mailbox public ID to target when the credential grants access to more than one mailbox. Omit when the credential is scoped to exactly one mailbox. in: query name: mailbox_id required: false schema: type: string requestBody: content: application/json: schema: $ref: '#/components/schemas/CreateMailboxDraft' required: true responses: '201': content: application/json: schema: $ref: '#/components/schemas/MailboxDraftResponse' description: Saved draft and its revision. headers: Location: description: Canonical draft URL. schema: type: string '400': content: application/json: schema: $ref: '#/components/schemas/ApiError' description: Request could not be completed. '401': content: application/json: schema: $ref: '#/components/schemas/ApiError' description: Request could not be completed. '403': content: application/json: schema: $ref: '#/components/schemas/ApiError' description: Request could not be completed. '404': content: application/json: schema: $ref: '#/components/schemas/ApiError' description: Request could not be completed. '409': content: application/json: schema: $ref: '#/components/schemas/ApiError' description: Request could not be completed. '413': content: application/json: schema: $ref: '#/components/schemas/ApiError' description: Request could not be completed. '422': content: application/json: schema: $ref: '#/components/schemas/ApiError' description: Request could not be completed. '429': content: application/json: schema: $ref: '#/components/schemas/ApiError' description: Request could not be completed. '500': content: application/json: schema: $ref: '#/components/schemas/ApiError' description: Request could not be completed. '503': content: application/json: schema: $ref: '#/components/schemas/ApiError' description: Request could not be completed. security: - bearerAuth: [] - oauth2: - mailbox.read - mailbox.drafts.write components: schemas: CreateMailboxDraft: additionalProperties: false properties: attachments: description: Attachments and inline images. items: additionalProperties: false properties: blob_id: description: An attachment uploaded to this mailbox. maxLength: 255 minLength: 1 type: string content_id: description: Content ID referenced by an inline image. maxLength: 998 minLength: 1 type: string content_type: description: Attachment media type. maxLength: 255 minLength: 1 type: string disposition: description: Whether the attachment appears within the message. enum: - attachment - inline type: string filename: description: Attachment filename. maxLength: 255 minLength: 1 type: string size_bytes: description: Attachment size in bytes; verified when saved. maximum: 7500000 minimum: 0 type: integer required: - blob_id - filename - content_type - size_bytes type: object maxItems: 10 type: array bcc: description: Hidden copied recipients. items: additionalProperties: false properties: email: description: Email address. format: email maxLength: 254 type: string name: description: Display name. maxLength: 255 type: - string - 'null' required: - email type: object maxItems: 50 type: array cc: description: Visible copied recipients. items: additionalProperties: false properties: email: description: Email address. format: email maxLength: 254 type: string name: description: Display name. maxLength: 255 type: - string - 'null' required: - email type: object maxItems: 50 type: array custom_headers: additionalProperties: type: string description: Custom X- headers preserved with this revision. type: object from: additionalProperties: false description: Authorised sender; defaults to this inbox. properties: email: description: Email address. format: email maxLength: 254 type: string name: description: Display name. maxLength: 255 type: - string - 'null' required: - email type: object html_body: description: HTML body, preserved when saved. maxLength: 1000000 type: string reply_to: description: Authorised reply addresses; defaults to this inbox. items: additionalProperties: false properties: email: description: Email address. format: email maxLength: 254 type: string name: description: Display name. maxLength: 255 type: - string - 'null' required: - email type: object maxItems: 20 type: array reply_to_message_id: description: Message in this inbox to reply to; thread headers are snapshotted. maxLength: 255 minLength: 1 type: string source: additionalProperties: false description: >- Source for this draft. Adoption requires Idempotency-Key. Explicit content fields override prepared defaults. properties: action: description: >- Prepare a reply, reply-all, forward or adopt an existing draft. Source content and attachments are saved with the draft. enum: - reply - reply_all - forward - adopt type: string message_id: description: Source message in this inbox. maxLength: 255 minLength: 1 type: string required: - message_id - action type: object subject: description: Subject; may be empty. maxLength: 998 type: string text_body: description: Plain-text body. maxLength: 1000000 type: string to: description: Primary recipients; at most 50 total across To, Cc and Bcc. items: additionalProperties: false properties: email: description: Email address. format: email maxLength: 254 type: string name: description: Display name. maxLength: 255 type: - string - 'null' required: - email type: object maxItems: 50 type: array type: object MailboxDraftResponse: allOf: - $ref: '#/components/schemas/SuccessEnvelope' - properties: data: $ref: '#/components/schemas/MailboxDraft' meta: $ref: '#/components/schemas/ResponseMeta' required: - data type: object unevaluatedProperties: false ApiError: additionalProperties: false properties: error: additionalProperties: false properties: code: description: Machine-readable error code enum: - invalid_parameter - missing_parameter - authentication_required - insufficient_permissions - not_found - conflict - limit_exceeded - idempotency_conflict - payload_too_large - validation_error - rate_limit_exceeded - service_unavailable - internal_error example: invalid_parameter type: string doc_url: description: Link to relevant documentation type: string errors: description: >- Accumulated per-field issues for validation errors. Only present on 400/422 responses. items: $ref: '#/components/schemas/ApiErrorDetail' type: array message: description: Human-readable error description type: string param: description: The parameter that caused the error type: string retryable: description: >- Whether the caller may safely retry this request. 4xx are typically false (except 429); 5xx are typically true. example: false type: boolean required: - code - message - retryable type: object meta: additionalProperties: false properties: request_id: example: req_clxxxxxxxxxxxxxxxxxxxxxxxxx type: string required: - request_id type: object ok: enum: - false type: boolean required: - ok - error - meta type: object SuccessEnvelope: properties: meta: additionalProperties: {} properties: {} type: object ok: enum: - true type: boolean required: - ok - meta type: object MailboxDraft: additionalProperties: false properties: attachments: description: Attachments and inline images. items: additionalProperties: false properties: blob_id: description: An attachment uploaded to this mailbox. maxLength: 255 minLength: 1 type: string content_id: description: Content ID referenced by an inline image. maxLength: 998 minLength: 1 type: string content_type: description: Attachment media type. maxLength: 255 minLength: 1 type: string disposition: description: Whether the attachment appears within the message. enum: - attachment - inline type: string filename: description: Attachment filename. maxLength: 255 minLength: 1 type: string size_bytes: description: Attachment size in bytes; verified when saved. maximum: 7500000 minimum: 0 type: integer required: - blob_id - filename - content_type - size_bytes type: object maxItems: 10 type: array bcc: description: Hidden copied recipients. items: additionalProperties: false properties: email: description: Email address. format: email maxLength: 254 type: string name: description: Display name. maxLength: 255 type: - string - 'null' required: - email type: object maxItems: 50 type: array cc: description: Visible copied recipients. items: additionalProperties: false properties: email: description: Email address. format: email maxLength: 254 type: string name: description: Display name. maxLength: 255 type: - string - 'null' required: - email type: object maxItems: 50 type: array custom_headers: additionalProperties: type: string description: Custom X- headers preserved with this revision. type: object failure_code: description: >- Safe failure reason. Correct failed draft content or current permissions before retrying. Never retry an uncertain send as a new message. enum: - preparation_failed - authorisation_revoked - send_rejected type: - string - 'null' from: additionalProperties: false description: Authorised sender; defaults to this inbox. properties: email: description: Email address. format: email maxLength: 254 type: string name: description: Display name. maxLength: 255 type: - string - 'null' required: - email type: object html_body: description: HTML body, preserved when saved. maxLength: 1000000 type: string id: description: Stable draft ID. type: string in_reply_to: description: Snapshotted parent message identifiers. items: type: string type: array message_id: description: Saved message ID; absent until saving finishes. type: - string - 'null' references: description: Snapshotted conversation identifiers. items: type: string type: array reply_to: description: Authorised reply addresses; defaults to this inbox. items: additionalProperties: false properties: email: description: Email address. format: email maxLength: 254 type: string name: description: Display name. maxLength: 255 type: - string - 'null' required: - email type: object maxItems: 20 type: array reply_to_message_id: description: Original message this draft replies to. type: string revision: description: Current draft revision. exclusiveMinimum: 0 type: integer schedule_version: description: >- Schedule control version. Changes whenever a schedule is created, moved or cancelled. minimum: 0 type: integer scheduled_for: description: >- Requested earliest send time, retained after sending. Null when no schedule is set. format: date-time type: - string - 'null' status: description: Saving or sending state. enum: - preparing - ready - scheduled - sending - queued - uncertain - failed - deleted type: string subject: description: Subject; may be empty. maxLength: 998 type: string text_body: description: Plain-text body. maxLength: 1000000 type: string to: description: Primary recipients; at most 50 total across To, Cc and Bcc. items: additionalProperties: false properties: email: description: Email address. format: email maxLength: 254 type: string name: description: Display name. maxLength: 255 type: - string - 'null' required: - email type: object maxItems: 50 type: array required: - id - revision - status - message_id - scheduled_for - schedule_version - failure_code - in_reply_to - references type: object ResponseMeta: additionalProperties: false properties: request_id: example: req_clxxxxxxxxxxxxxxxxxxxxxxxxx type: string required: - request_id type: object ApiErrorDetail: additionalProperties: false properties: code: description: >- Machine-readable issue code from the validator (e.g. zod issue code). example: invalid_string type: string field: description: Dot-path of the offending request field. example: recipient.email type: string message: description: Human-readable issue description. type: string required: - field - code - message type: object securitySchemes: bearerAuth: bearerFormat: API Key description: >- Sendmux API key. Use a root API key for Management API routes, or a mailbox credential for Mailbox API routes. Obtain keys from the dashboard under API Keys. scheme: bearer type: http oauth2: description: >- Use the authorisation-code flow with S256 PKCE and resource=https://sendmux.ai/api. The user selects the team, API access and mailboxes during consent. OAuth access tokens authenticate HTTP API requests; use separate credentials for SMTP and IMAP. flows: authorizationCode: authorizationUrl: https://app.sendmux.ai/oauth/authorize refreshUrl: https://app.sendmux.ai/oauth/token scopes: analytics.*: All analytics operations analytics.read: View key usage analytics and verification logs billing.*: All billing operations billing.auto_topup: Configure auto top-up settings billing.read: View balance, transactions, invoices billing.topup: Purchase balance top-ups domain.*: All domain operations domain.create: Add sending domains domain.delete: Remove domains domain.read: List/view domains and DNS status domain.verify: Trigger domain verification email.receive: Authorise email reception email.send: Send email through the HTTP API key.*: All key management operations key.create: Create new API keys (both root and mailbox) key.read: List/view API keys and their metadata key.revoke: Revoke API keys key.rotate: Rotate API keys logs.*: All log operations logs.read: View delivery logs mailbox.admin.*: All mailbox admin operations mailbox.admin.create: Create mailboxes (admin-level) mailbox.admin.delete: Delete mailboxes (admin-level) mailbox.admin.manage: Manage all mailbox settings mailbox.admin.read: List/view mailboxes (admin-level) mailbox.drafts.write: Create and edit saved mailbox drafts mailbox.read: Read mailbox contents (folders, messages) mailbox.settings.update: Update own mailbox settings (signature, auto-reply) provider.*: All provider operations provider.create: Add email provider accounts (Google, Microsoft, SMTP) provider.delete: Remove provider accounts provider.read: List/view provider accounts and connection status provider.update: Update provider settings, refresh tokens routing.*: All routing operations routing.create: Create delivery groups routing.delete: Remove delivery groups routing.read: List/view delivery groups and routing rules routing.update: Update delivery group configuration team.*: All team operations team.members.invite: Invite team members team.members.remove: Remove team members team.members.roles: Change member roles team.read: View team settings and members team.update: Update team settings webhook.*: All webhook operations webhook.create: Create webhook subscriptions webhook.delete: Delete webhook subscriptions webhook.manage: Rotate signing secret + send test events webhook.read: List/view webhook subscriptions webhook.update: Update webhook URL, event types, enabled flag tokenUrl: https://app.sendmux.ai/oauth/token type: oauth2 ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.