> ## Documentation Index > Fetch the complete documentation index at: https://docs.upwell.com/llms.txt > Use this file to discover all available pages before exploring further. # Generate Upload Presigned Url > Generate a presigned URL for direct S3 file upload. **Integration notes:** - If you provide `sourceSystem` you must also provide `sourceSystemId` (and vice versa) — the `documents_source_system_pair_nullity_chk` constraint requires both or neither. - On the subsequent `PUT` to the returned `uploadUrl`, prefer an `ArrayBuffer` body over `Blob`. Wrapping in a `Blob` with an explicit type can cause some Node fetch implementations to add headers that aren't in `X-Amz-SignedHeaders`, breaking the SigV4 signature. See [Integration patterns](/integration-patterns#document-upload-two-step-presigned-url). ## OpenAPI ````yaml /api-reference/openapi.json post /api/rest/generate-upload-presigned-url openapi: 3.1.0 info: description: >- Upwell is Accounts Receivable automation software for the logistics industry. We serve freight brokers, carriers, factors, and anyone who needs to get transportation invoices paid. Learn more at: - [Upwell.com](https://upwell.com) title: Upwell REST API version: 3.30.2 termsOfService: https://upwell.com/legal contact: name: Upwell url: https://upwell.com email: contact@upwell.com servers: - url: https://api.upwell.com description: Production server - url: https://staging.api.upwell.com description: Staging server security: [] tags: - name: Invoice Approval description: Endpoints for managing customer invoice approval workflow paths: /api/rest/generate-upload-presigned-url: post: tags: - Documents summary: Generate Upload Presigned Url description: >- Generate a presigned URL for direct S3 file upload. **Integration notes:** - If you provide `sourceSystem` you must also provide `sourceSystemId` (and vice versa) — the `documents_source_system_pair_nullity_chk` constraint requires both or neither. - On the subsequent `PUT` to the returned `uploadUrl`, prefer an `ArrayBuffer` body over `Blob`. Wrapping in a `Blob` with an explicit type can cause some Node fetch implementations to add headers that aren't in `X-Amz-SignedHeaders`, breaking the SigV4 signature. See [Integration patterns](/integration-patterns#document-upload-two-step-presigned-url). parameters: - description: >- Your API key will be used for authentication of the request. `Authorization: YOUR_API_KEY` in: header name: authorization schema: type: string requestBody: content: application/json: schema: properties: input: $ref: '#/components/schemas/GenerateUploadUrlInput' type: object description: >- Query parameters can also be provided in the request body as a JSON object required: true responses: '200': content: application/json: schema: properties: generateUploadPresignedUrl: nullable: false properties: documentId: nullable: true title: String type: string uploadUrl: nullable: false title: String type: string title: UploadPresignedUrlResponse type: object description: Responses for POST /api/rest/generate-upload-presigned-url components: schemas: GenerateUploadUrlInput: nullable: false properties: associationId: nullable: true title: String type: string associationType: $ref: '#/components/schemas/AllowedFileAssociationTypeEnum' documentType: $ref: '#/components/schemas/AllowedDocumentType' fileName: nullable: false title: String type: string isPod: nullable: true title: Boolean type: boolean mimeType: nullable: false title: String type: string sourceSystem: nullable: true title: String type: string sourceSystemId: nullable: true title: String type: string visibleToCarrier: nullable: true title: Boolean type: boolean visibleToCustomer: nullable: true title: Boolean type: boolean title: GenerateUploadUrlInput type: object AllowedFileAssociationTypeEnum: description: The type of the file association enum: - CARRIER_INVOICE - INVOICE - PURCHASE_ORDER - SHIPMENT - VENDOR_INVOICE nullable: false title: AllowedFileAssociationTypeEnum AllowedDocumentType: description: The type of the document enum: - ACCESSORIAL_RECEIPT - ADVANCE_REQUEST - AGENT_INVOICE - ARRIVAL_NOTICE - ASBESTOS_DECLARATION - AUSFTA - AUTHORITY - AUTH_RELEASE - B3_CANADIAN_ENTRY - BALANCE_DUE - BILL_OF_LADING - CARRIER_ACH_SETUP_FORM - CARRIER_BOOKING_REQUEST - CARRIER_INSURANCE_CERTIFICATE - CARRIER_INVOICE - CARRIER_INVOICE_SUMMARY - CARRIER_INVOICE_WITH_SUPPORTING_DOCUMENTATION - CARRIER_RATE_CONFIRMATION - CARRIER_W9 - CARTAGE_ADVICE_WITH_RECEIPT - CERTIFICATE_OF_ORIGIN - CFDI - CLAIM - CLAIM_NOTICE - COMCHECK - COMMERCIAL_INVOICE - CONSIGNMENT_SECURITY_DECLARATION - CONTRACT - CORRECTION_NOTICE - COVER_SHEET - CREDIT_APPLICATION - CUSTOMER_DOCUMENTS_OTHER - CUSTOMER_INVOICE - CUSTOMER_INVOICE_WITH_SUPPORTING_DOCUMENTATION - CUSTOMER_RATE_CONFIRMATION - CUSTOMER_RELEASE - CUSTOMS_AUTHORITY - CUSTOMS_CLEARANCE_REQUEST - CUSTOMS_DOCUMENT - CUSTOMS_ENTRY_SUMMARY - CUSTOMS_POWER_OF_ATTORNEY - DANGEROUS_GOODS_DECLARATION - DELIVERY_ORDER - DELIVERY_PHOTO - DELIVERY_RECEIPT - DEMURRAGE_RECEIPT - DETENTION_APPROVAL - DOCUMENT_BUNDLE - DOCUMENT_PACKET - DRIVER_FORM - ELECTRONIC_INTERCHANGE_RECEIPT - EMAIL_APPROVAL - EMAIL_SIGNATURE_IMAGE - ESCORT_RECEIPT - EXIT_PASS - EXPORT_AUTHORITY - EXPORT_DECLARATION - FACTOR_INVOICE - FERRY_RECEIPT - FINE - FORM_1113_PUBLIC_VOUCHER - FREETIME_NOTIFICATION - FREIGHT_LABEL - FUEL_RECEIPT - FUMIGATION_CERTIFICATE - FUNDING_REQUEST_FORM - GATE_PASS - GOVERNMENT_BOL - HIDDEN_BOL - HOUSE_AIRWAY_BILL - HOUSE_BOL - HOUSE_OCEAN_BOL - INSPECTION_CERTIFICATE - INSTRUCTION_PAGE - INTERMODAL_IN_TRANSIT_NOTICE - INTERNAL_DOCUMENTS_OTHER - INTERNAL_PROOF_OF_DELIVERY - INTERNATIONAL_BOL - INVOICE_STATEMENT - ISF_FILING_INSTRUCTION - LAYOVER_APPROVAL - LETTER_OF_ASSIGNMENT - LETTER_OF_CREDIT - LUMPER_APPROVAL - LUMPER_RECEIPT - MANIFEST - MASTER_AIRWAY_BILL - MASTER_BOL - MASTER_OCEAN_BOL - MOTOR_VEHICLE_CERT - MSDS - NAFTA_CERT - NMFC_W_I_CERT - NOTICE_OF_ASSIGNMENT - NOTICE_OF_RELEASE - OTHER - PACKING_DECLARATION - PACKING_SLIP - PALLET_RECEIPT - PERMIT_TO_TRANSFER - PER_DIEM_RECEIPT - PICKUP_NUMBER - PRE_ALERT - PROFORMA_INVOICE - PROOF_OF_DELIVERY - PURCHASE_ORDER - REMITTANCE - RUN_TICKET - SANITARY_CERTIFICATE - SCALE_TICKET - SHIPPERS_LETTER - SHIPPER_SECURITY_DECLARATION - SOLAS_FORM - SPOT_QUOTE_APPROVAL - STEAMING_RECEIPT - SUPPORTING_DOCUMENTATION - TELEX_RELEASE - TOLL_RECEIPT - TONU_APPROVAL - TRACKING_STATUS - TRAILER_INTERCHANGE_REPORT - TRUCK_BOL - UNKNOWN - US_CUSTOMS_DOC - VENDOR_INVOICE - VETERINARY_CERTIFICATE - VGM_CONTAINER_INFO - VOIDED_CHECK - WASH_RECEIPT - WAYBILL - WEIGHT_MEASUREMENT_REPORT - WEIGHT_TICKET - WEIGHT_UNLOADED nullable: false title: AllowedDocumentType ````