> ## Documentation Index > Fetch the complete documentation index at: https://docs.commenda.io/llms.txt > Use this file to discover all available pages before exploring further. # Upload a file > Upload a file with multipart/form-data and receive a reusable fileId. Stores bytes only; does not link the file to any other resource. Use the returned fileId with a separate attach call to put the file to work. Upload a file with `multipart/form-data` and receive a reusable `fileId`. This endpoint stores bytes only — it does not link the file to a person, a business entity, or a participant document. Use the returned `fileId` with a separate attach call to put the file to work. This is the only Commenda Partner API endpoint that accepts binary content. Files are scoped to the customer named in the path and can be referenced by any downstream attach call that takes a `fileId` for that customer. ## When to use this endpoint Call this before [upserting a participant document](/engine/incorporation/partner-incorporation-participant-documents-PUT) for an incorporation, or before any future endpoint that accepts a `fileId`. A single `fileId` can be reused across multiple attach calls without re-uploading bytes. ## Request Send a single multipart part named `file` containing the binary body. The part's filename and detected MIME type are stored as `fileName` and `mimeType` on the file record. No other fields are accepted. ## Limits | Limit | Value | | ------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | Maximum file size | 100 MB per request | | Request timeout | 120 seconds | | Accepted MIME types | `application/pdf`, `image/png`, `image/jpeg`, `image/heic`, `image/heif`, `image/tiff`, `image/webp`, `application/msword`, `application/vnd.openxmlformats-officedocument.wordprocessingml.document` | Requests that exceed the file-size limit return `413 Payload Too Large`. Requests with an unsupported MIME type return `415 Unsupported Media Type`. Commenda detects the MIME type from the uploaded part's content rather than trusting the declared `Content-Type` alone, so renaming a file extension does not change which limits apply. If you need to upload files larger than 100 MB, contact Commenda. A separate direct-to-object-storage upload flow is available for those cases. ## Example ```bash theme={null} curl --request POST \ --url 'https://api.prod.commenda.io/api/v1/partner/commenda-os/customers/77/files' \ --header 'x-api-key: ' \ --form 'file=@./passport.pdf;type=application/pdf' ``` ```json theme={null} { "file": { "fileId": 456, "fileName": "passport.pdf", "mimeType": "application/pdf", "fileSize": 382144, "customerId": 77 } } ``` ## OpenAPI ````yaml POST /partner/commenda-os/customers/{customerId}/files openapi: 3.0.1 info: title: Commenda Public APIs description: >- APIs for Commenda entity management, partner incorporation, indirect tax, compliance, and corporate operations. license: name: NONE url: NONE version: 1.0.0 servers: - url: https://api.prod.commenda.io/api/v1 description: Commenda platform APIs, including Partner Incorporation and Commenda OS. - url: https://transaction-tax.api.in.commenda.io/api/v1 description: Global Indirect Tax API. security: - bearerAuth: [] paths: /partner/commenda-os/customers/{customerId}/files: post: summary: Upload a file description: >- Upload a file with multipart/form-data and receive a reusable fileId. Stores bytes only; does not link the file to any other resource. Use the returned fileId with a separate attach call to put the file to work. operationId: uploadPartnerCommendaOsCustomerFile parameters: - name: customerId in: path required: true schema: type: integer description: Commenda customer identifier. requestBody: required: true content: multipart/form-data: schema: $ref: '#/components/schemas/CommendaOsCustomerFileUploadRequest' responses: '201': description: File uploaded successfully content: application/json: schema: $ref: '#/components/schemas/CommendaOsCustomerFileResponse' '400': description: Missing file part or malformed multipart body content: application/json: schema: $ref: '#/components/schemas/CommendaOsPartnerError' '401': description: Missing or invalid partner API key content: application/json: schema: $ref: '#/components/schemas/CommendaOsPartnerError' '403': description: Customer does not belong to this partner firm content: application/json: schema: $ref: '#/components/schemas/CommendaOsPartnerError' '404': description: Customer not found content: application/json: schema: $ref: '#/components/schemas/CommendaOsPartnerError' '413': description: Uploaded file exceeds the 100 MB per-request size limit content: application/json: schema: $ref: '#/components/schemas/CommendaOsPartnerError' '415': description: Detected MIME type of the uploaded file is not in the accepted list content: application/json: schema: $ref: '#/components/schemas/CommendaOsPartnerError' security: - xApiKeyAuth: [] servers: - url: https://api.prod.commenda.io/api/v1 components: schemas: CommendaOsCustomerFileUploadRequest: type: object required: - file properties: file: type: string format: binary description: >- Binary file part. The part filename and detected MIME type are recorded on the file. No other multipart fields are accepted. CommendaOsCustomerFileResponse: type: object required: - file properties: file: $ref: '#/components/schemas/CommendaOsCustomerFile' CommendaOsPartnerError: type: object required: - statusCode - message - error properties: statusCode: type: integer description: HTTP status code for the error response. message: description: >- Error message returned by the API. Exact text varies by failure mode. oneOf: - type: string - type: array items: type: string error: type: string description: Standard error label for the response status. CommendaOsCustomerFile: type: object required: - fileId - fileName - mimeType - fileSize - customerId properties: fileId: type: integer description: >- Commenda file id. Pass to a downstream attach call (for example, create a customer document or upsert a participant document) to put the file to work. example: 456 fileName: type: string example: passport.pdf mimeType: type: string example: application/pdf fileSize: type: integer nullable: true example: 382144 customerId: type: integer example: 77 securitySchemes: bearerAuth: type: http scheme: bearer xApiKeyAuth: type: apiKey in: header name: x-api-key ````