> ## Documentation Index > Fetch the complete documentation index at: https://docs.lighton.ai/llms.txt > Use this file to discover all available pages before exploring further. # Download a document file > Download a document file. Returns the original file by default. Use the purpose parameter to request a specific version (e.g. rendered_pdf for frontend viewers). ## OpenAPI ````yaml /api-reference/openapi-v3.yaml get /api/v3/files/{id}/download openapi: 3.1.0 info: title: LightOn API version: 3.15.0 (v3) description: >- LightOn gives you an API to search, parse, and ingest documents at scale. Build knowledge-retrieval pipelines without managing vector databases or OCR models. servers: - url: https://paradigm.lighton.ai security: [] tags: - name: Agents description: Operations about agents - name: Threads description: Operations about agents conversation threads - name: Tools description: Operations about native tools - name: Models description: Operations about AI models - name: MCP description: Operations about MCP servers - name: Sources description: Operations about sources used by agents conversation threads - name: Artifacts description: Operations about artifacts generated by agents conversation threads - name: Agent description: >- Operations about agents (deprecated). Please use the 'Agents' API component instead. - name: Files description: Operations about files - name: Facets description: Operations about facets - name: Tags description: Operations about tags - name: Workspaces description: Operations about workspaces - name: Files Processing description: Operations about files processing - name: Users description: Operations about users - name: API Keys description: Operations about API keys - name: User Groups description: Operations about user groups - name: SCIM description: Operations about SCIM paths: /api/v3/files/{id}/download: get: tags: - Files summary: Download a document file description: >- Download a document file. Returns the original file by default. Use the purpose parameter to request a specific version (e.g. rendered_pdf for frontend viewers). operationId: api_v3_files_download_retrieve parameters: - in: path name: id schema: type: integer description: A unique integer value identifying this Document. required: true - in: query name: purpose schema: type: string enum: - original - rendered_pdf - transcript description: >- Which file version to serve. Defaults to 'original'. Falls back to 'original' if the requested purpose has no associated file. responses: '200': description: Binary file content or sanitized markdown text '401': content: application/json: schema: $ref: '#/components/schemas/APIV3ErrorResponse' examples: Unauthorized: value: id: null code: 401 error: unauthorized detail: >- Authentication credentials were not provided or are invalid. doc_url: https://developers.lighton.ai/errors#unauthorized description: Authentication credentials were not provided or are invalid '404': content: application/json: schema: $ref: '#/components/schemas/APIV3ErrorResponse' examples: NotFound: value: id: null code: 404 error: not_found detail: The requested resource was not found. doc_url: https://developers.lighton.ai/errors#not_found summary: Not Found description: The requested resource was not found '422': content: application/json: schema: $ref: '#/components/schemas/APIV3ValidationErrorResponse' examples: ValidationError: value: id: null code: 422 error: validation_error detail: One or more fields failed validation. doc_url: https://developers.lighton.ai/errors#validation_error fields: : - error: required detail: This field is required. summary: Validation Error description: Request body is valid JSON but one or more fields failed validation '503': description: >- API is under maintenance. Check `GET /api/v3/system/status` for active periods and retry. content: application/json: schema: $ref: '#/components/schemas/ServiceMaintenance503' security: - bearerAuth: [] components: schemas: APIV3ErrorResponse: type: object properties: id: type: - string - 'null' description: >- Job/resource id when one already exists (useful for async error diagnosis); null otherwise. code: type: integer description: HTTP status code error: type: string description: Error code used by the UI as a translation key detail: type: string description: Human-readable error message for developers doc_url: type: string description: Link to the error-code documentation page required: - code - detail - doc_url - error - id APIV3ValidationErrorResponse: type: object properties: id: type: - string - 'null' description: >- Job/resource id when one already exists (useful for async error diagnosis); null otherwise. code: type: integer description: HTTP status code error: type: string description: Error code used by the UI as a translation key detail: type: string description: Human-readable error message for developers doc_url: type: string description: Link to the error-code documentation page fields: type: object additionalProperties: type: array items: $ref: '#/components/schemas/APIV3FieldError' description: Field-level validation errors keyed by field name required: - code - detail - doc_url - error - id ServiceMaintenance503: type: object description: >- Returned by the maintenance middleware when the requested endpoint is blocked. required: - detail - error - mode properties: detail: type: string example: System is under maintenance. error: type: string example: service_maintenance mode: type: string enum: - full_shutdown - warning_banner description: >- `full_shutdown` blocks all traffic; `warning_banner` also blocks and shows a dismissible toast. reason: type: string description: Operator-supplied maintenance reason, if any. started_at: type: string format: date-time endpoint_category_names: type: array items: type: string description: >- Non-empty only for category-scoped periods. Empty means all endpoints are affected. APIV3FieldError: type: object properties: error: type: string description: Error code / translation key detail: type: string description: Human-readable description of the field error required: - detail - error securitySchemes: bearerAuth: type: http scheme: bearer description: >- Bearer authentication header of the form `Bearer `, where `` is your auth token. ````