> ## 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. # Request attachment text > Extract readable text from an attachment up to 7500000 bytes, at no extra charge. Repeating this request reuses the same current source extraction for 24 hours; no request body or Idempotency-Key is needed. Conversion runs for at most 30 seconds. OCR is unavailable. Current mailbox access and the source attachment are checked before serving cached text. If extraction cannot complete, use the original attachment download. ## OpenAPI ````yaml /openapi-app.json post /mailbox/messages/{message_id}/attachments/{attachment_id}/text 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/messages/{message_id}/attachments/{attachment_id}/text: post: tags: - Mailbox API summary: Request attachment text description: >- Extract readable text from an attachment up to 7500000 bytes, at no extra charge. Repeating this request reuses the same current source extraction for 24 hours; no request body or Idempotency-Key is needed. Conversion runs for at most 30 seconds. OCR is unavailable. Current mailbox access and the source attachment are checked before serving cached text. If extraction cannot complete, use the original attachment download. operationId: mailboxRequestAttachmentText parameters: - description: Message ID in the selected mailbox. in: path name: message_id required: true schema: description: Message ID in the selected mailbox. type: string - description: Attachment ID from that message. in: path name: attachment_id required: true schema: description: Attachment ID from that message. type: string - description: >- Maximum UTF-8 text bytes returned. Default 262144; maximum 1048576. Applies to cached results too. in: query name: max_bytes required: false schema: description: >- Maximum UTF-8 text bytes returned. Default 262144; maximum 1048576. Applies to cached results too. maximum: 1048576 minimum: 1 type: integer - 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 responses: '200': content: application/json: examples: ready: value: data: expires_at: '2026-09-30T00:00:00.000Z' format: markdown id: ext_example outcome: ready status: complete text: |- # Invoice Amount: $25 truncated: false meta: request_id: req_example ok: true unsupported: value: data: expires_at: '2026-09-30T00:00:00.000Z' format: markdown id: ext_example outcome: unsupported status: complete text: '' truncated: false meta: request_id: req_example ok: true schema: $ref: '#/components/schemas/MailboxAttachmentTextResponse' description: >- Conversion completed. Check outcome before using text; original attachment downloads remain available. headers: ETag: description: Current response validator, returned by GET. schema: type: string '202': content: application/json: example: data: expires_at: '2026-09-30T00:00:00.000Z' format: markdown id: ext_example outcome: null status: pending text: null truncated: false meta: request_id: req_example ok: true schema: $ref: '#/components/schemas/MailboxAttachmentTextResponse' description: Extraction is pending or running. Poll GET on this same URL. headers: ETag: description: Current response validator, returned by GET. 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: Source attachment or unexpired extraction not found. '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 components: schemas: MailboxAttachmentTextResponse: allOf: - $ref: '#/components/schemas/SuccessEnvelope' - properties: data: $ref: '#/components/schemas/MailboxAttachmentText' 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 MailboxAttachmentText: additionalProperties: false properties: expires_at: description: Cache expiry. A new POST is needed after expiry. format: date-time type: string format: description: Extracted text format. enum: - markdown type: string id: description: Extraction ID. example: ext_example type: string outcome: anyOf: - enum: - ready - unsupported - encrypted - malformed - ocr_required - resource_limit - source_unavailable - failed type: string - type: 'null' description: >- Null while pending or running. Only ready contains extracted text; other outcomes contain an empty string. status: description: Poll until complete to read the outcome. enum: - pending - running - complete type: string text: description: >- Markdown text, or null until complete. Limited to max_bytes in UTF-8. type: - string - 'null' truncated: description: True when conversion or the requested output bound omitted text. type: boolean required: - id - status - outcome - text - format - truncated - expires_at 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.