> ## Documentation Index > Fetch the complete documentation index at: https://docs.ndi.nace.ai/llms.txt > Use this file to discover all available pages before exploring further. # get_upload_session > Read a chunked upload's lifecycle state and landed parts. Cost class: **fast**. The resume entry point: after a dropped connection (or a page reload), diff ``parts`` against what was already sent and PUT only what is missing — never re-derive part numbers, and never resend a part that already landed. ## OpenAPI ````yaml /openapi.json get /v1/workspaces/{workspace_id}/upload-sessions/{session_id} openapi: 3.1.0 info: description: >- Document intelligence: parse, split, classify, extract, and ground files, or build a searchable workspace. Authenticate with ``X-API-Key``. title: NDI Platform API version: 0.1.0 servers: - url: https://ndi-api.nace.ai security: [] tags: [] paths: /v1/workspaces/{workspace_id}/upload-sessions/{session_id}: get: tags: - files summary: get_upload_session description: >- Read a chunked upload's lifecycle state and landed parts. Cost class: **fast**. The resume entry point: after a dropped connection (or a page reload), diff ``parts`` against what was already sent and PUT only what is missing — never re-derive part numbers, and never resend a part that already landed. operationId: >- get_upload_session_v1_workspaces__workspace_id__upload_sessions__session_id__get parameters: - description: Workspace identifier. in: path name: workspace_id required: true schema: description: Workspace identifier. format: uuid title: Workspace Id type: string - description: Upload session identifier. in: path name: session_id required: true schema: description: Upload session identifier. format: uuid title: Session Id type: string responses: '200': content: application/json: schema: $ref: '#/components/schemas/UploadSessionStatusResponse' description: Successful Response '504': content: application/json: schema: $ref: '#/components/schemas/ErrorEnvelope' description: Gateway Timeout default: content: application/json: example: error: code: invalid_request detail: null message: >- Request body has extra fields that this operation does not accept. request_id: req-01j9k2n3p4q5r6s7t8v9 retryable: false schema: $ref: '#/components/schemas/ErrorEnvelope' description: >- Typed error envelope used by every 4xx and 5xx. ``error.code`` distinguishes the failure; HTTP status is a consequence of the code. security: - UploadSessionTokenHeader: [] components: schemas: UploadSessionStatusResponse: additionalProperties: false description: >- Result of ``GET .../upload-sessions/{session_id}`` — for resuming after a drop. A resuming client diffs ``parts`` against what it already sent and PUTs only what is missing; it never needs to re-derive part numbers itself. properties: chunk_size: title: Chunk Size type: integer declared_size_bytes: title: Declared Size Bytes type: integer expires_at: format: date-time title: Expires At type: string parts: description: Parts landed so far, unordered. items: $ref: '#/components/schemas/UploadSessionPart' title: Parts type: array received_bytes: description: Sum of parts[*].size_bytes. title: Received Bytes type: integer session_id: format: uuid title: Session Id type: string status: enum: - open - completing - completed - aborted title: Status type: string total_parts: title: Total Parts type: integer required: - session_id - status - chunk_size - total_parts - parts - received_bytes - declared_size_bytes - expires_at title: UploadSessionStatusResponse type: object ErrorEnvelope: description: Every non-2xx body on ``/v1``. example: error: code: invalid_request detail: null message: Request body has extra fields that this operation does not accept. request_id: req-01j9k2n3p4q5r6s7t8v9 retryable: false properties: error: $ref: '#/components/schemas/Error' required: - error title: ErrorEnvelope type: object UploadSessionPart: additionalProperties: false description: >- One landed part, as reported by ``GET .../upload-sessions/{session_id}``. properties: part_number: title: Part Number type: integer size_bytes: title: Size Bytes type: integer required: - part_number - size_bytes title: UploadSessionPart type: object Error: description: The error object, per spec 12 §1.8. properties: code: $ref: '#/components/schemas/ErrorCode' detail: anyOf: - additionalProperties: true type: object - type: 'null' description: Structured payload, when the code carries one. title: Detail message: description: Human- and model-readable; says what to do differently. title: Message type: string request_id: description: Per-request correlation id; matches the ``X-Request-Id`` header. title: Request Id type: string retryable: description: Whether retrying the identical request could succeed. title: Retryable type: boolean required: - code - message - retryable - request_id title: Error type: object ErrorCode: description: |- Every error the ``/v1`` surface can return. Clients must treat this as an **open** enum: a new member is an additive change (spec 12 §9), and a client that crashes on an unknown code makes every future error a breaking change. enum: - invalid_request - unsupported_file_type - file_too_large - invalid_schema - invalid_sql - invalid_path_prefix - command_not_permitted - batch_too_large - domain_validation_failed - default_label_required - wait_required_for_zero_retention - workspace_not_found - file_not_found - job_not_found - upload_not_found - node_not_found - schema_not_found - domain_not_found - session_not_found - access_label_not_found - path_conflict - schema_version_conflict - access_label_name_taken - workspace_name_taken - access_label_in_use - upload_expired - file_not_ingested - workspace_deleting - workspace_not_deletable - ingestion_in_progress - job_not_cancellable - confirmation_required - domain_not_published - domain_in_use - reserved_domain_slug - kg_not_built - kg_build_in_progress - session_busy - range_not_satisfiable - result_expired - access_denied - access_backstop_violation - access_mode_not_implemented - rate_limited - concurrency_limit_reached - quota_exceeded - corrupt_file - zero_byte_file - encrypted_file - parse_failed - ocr_failed - conversion_failed - sheetless_workbook - unplayable_media - unclassified_pages - job_cancelled - job_timeout - upstream_unavailable - internal_error - unauthorized - not_implemented title: ErrorCode type: string securitySchemes: UploadSessionTokenHeader: description: Session token from POST /v1/workspaces/{workspace_id}/upload-sessions. in: header name: X-Upload-Token type: apiKey ````