--- title: "Creates an intermediate [Upload](/docs/api-reference/uploads/object) object that you can add [Parts](/docs/api-reference/uploads/part-object) to. Currently, an Upload can accept at most 8 GB in total and expires after an hour after you create it. Once you complete the Upload, we will create a [File](/docs/api-reference/files/object) object that contains all the parts you uploaded. This File is usable in the rest of our platform as a regular File object. For certain `purpose` values, the correct `mime_type` must be specified. Please refer to documentation for the [supported MIME types for your use case](/docs/assistants/tools/file-search#supported-files). For guidance on the proper filename extensions for each purpose, please follow the documentation on [creating a File](/docs/api-reference/files/create). Returns the Upload object with status `pending`." method: POST path: "/uploads" tags: ["Uploads"] --- # Creates an intermediate [Upload](/docs/api-reference/uploads/object) object that you can add [Parts](/docs/api-reference/uploads/part-object) to. Currently, an Upload can accept at most 8 GB in total and expires after an hour after you create it. Once you complete the Upload, we will create a [File](/docs/api-reference/files/object) object that contains all the parts you uploaded. This File is usable in the rest of our platform as a regular File object. For certain `purpose` values, the correct `mime_type` must be specified. Please refer to documentation for the [supported MIME types for your use case](/docs/assistants/tools/file-search#supported-files). For guidance on the proper filename extensions for each purpose, please follow the documentation on [creating a File](/docs/api-reference/files/create). Returns the Upload object with status `pending`. `POST /uploads` ## Request body - CreateUploadRequest - `filename` string, required — The name of the file to upload. - `purpose` 'assistants' | 'batch' | 'fine-tune' | 'vision', required — The intended purpose of the uploaded file. See the [documentation on File purposes](/docs/api-reference/files/create#files-create-purpose). - `bytes` integer, required — The number of bytes in the file you are uploading. - `mime_type` string, required — The MIME type of the file. This must fall within the supported MIME types for your file purpose. See the supported MIME types for assistants and vision. - `expires_after` FileExpirationAfter — The expiration policy for a file. By default, files with `purpose=batch` expire after 30 days and all other files are persisted until they are manually deleted. - `anchor` 'created_at', required — Anchor timestamp after which the expiration policy applies. Supported anchors: `created_at`. - `seconds` integer, required — The number of seconds after the anchor time that the file will expire. Must be between 3600 (1 hour) and 2592000 (30 days). ## Response `200` OK - Upload — The Upload object can accept byte chunks in the form of Parts. - `id` string, required — The Upload unique identifier, which can be referenced in API endpoints. - `created_at` integer, required — The Unix timestamp (in seconds) for when the Upload was created. - `filename` string, required — The name of the file to be uploaded. - `bytes` integer, required — The intended number of bytes to be uploaded. - `purpose` string, required — The intended purpose of the file. [Please refer here](/docs/api-reference/files/object#files/object-purpose) for acceptable values. - `status` 'pending' | 'completed' | 'cancelled' | 'expired', required — The status of the Upload. - `expires_at` integer, required — The Unix timestamp (in seconds) for when the Upload will expire. - `object` 'upload' — The object type, which is always "upload". - `file` object, nullable — The ready File object after the Upload is completed. - `id` string, required — The file identifier, which can be referenced in the API endpoints. - `bytes` integer, required — The size of the file, in bytes. - `created_at` integer, required — The Unix timestamp (in seconds) for when the file was created. - `expires_at` integer — The Unix timestamp (in seconds) for when the file will expire. - `filename` string, required — The name of the file. - `object` 'file', required — The object type, which is always `file`. - `purpose` 'assistants' | 'assistants_output' | 'batch' | 'batch_output' | 'fine-tune' | 'fine-tune-results' | 'vision' | 'user_data', required — The intended purpose of the file. Supported values are `assistants`, `assistants_output`, `batch`, `batch_output`, `fine-tune`, `fine-tune-results`, `vision`, and `user_data`. - `status` 'uploaded' | 'processed' | 'error', required — Deprecated. The current status of the file, which can be either `uploaded`, `processed`, or `error`. - `status_details` string — Deprecated. For details on why a fine-tuning training file failed validation, see the `error` field on `fine_tuning.job`. ## Changes > 82 revisions in range; 5 could not be searched. - **2026-05-13** `74cbcf73838f` — 1 warning, 1 info - added the new `user_data` enum value to the `file/allOf[subschema #1: OpenAIFile]/purpose` response property for the response status `200` - added the new optional request property `expires_after` - **2025-03-11** `6ab43fe7798e` — 1 info - added the optional property `file/allOf[subschema #1: OpenAIFile]/expires_at` to the response with the `200` status - **2025-01-31** `fc164a27fdb9` — 7 breaking, 1 warning, 1 info - removed the required property `file/bytes` from the response with the `200` status - removed the required property `file/created_at` from the response with the `200` status - removed the required property `file/filename` from the response with the `200` status - removed the required property `file/id` from the response with the `200` status - …5 more - **2025-01-31** `15156e46769c` — 1 breaking, 9 info - the response property `file` became nullable for the status `200` - added the optional property `file/status_details` to the response with the `200` status - removed `#/components/schemas/OpenAIFile, subschema #2` from the `file` response property `allOf` list for the response status `200` - added the required property `file/bytes` to the response with the `200` status - …6 more - …earlier changes not shown [Full history](https://skmtc.dev/openai/apis/openapi/changes/uploads/post.md) --- [API](https://skmtc.dev/openai/apis/openapi.md) · [All operations](https://skmtc.dev/openai/apis/openapi/llms.txt) · [OpenAPI document](https://skmtc-service-production.skmtc.workers.dev/v1/apis/openai/openapi/revisions/959ef977e135/schema)