> ## Documentation Index > Fetch the complete documentation index at: https://developer.fin.com/llms.txt > Use this file to discover all available pages before exploring further. # Attach Documents to Business Customer V2 > Attach formation, ownership, and supporting documents to an existing business customer. Documents are categorised into three arrays — formation_documents, ownership_documents, and supporting_documents — replacing the v1 ownership_structure / company_details / legal_presence structure. * Upload files first using the [Upload document](https://developer.fin.com/api-reference/customers/upload-document) endpoint to obtain URIs, then reference them here. * Parse `tos_policies_value` from the `tos_policies_url` returned by `POST /v2/customers/business` and include it in this request. ## Document Type Reference See [Entity-wise document requirement](https://developer.fin.com/guides/compliance-and-regulatory/entity-wise-document-requirement) for all valid `type` values per category and entity type. ## OpenAPI ````yaml POST /v2/customers/{customer_id}/business/attach openapi: 3.1.0 info: title: Fin.com API version: 1.0.0 description: A simple API specification servers: - url: https://sandbox.api.fin.com description: Sandbox server - url: https://api.fin.com description: Production server security: [] tags: - name: Authentication description: A modified OAuth 2.0 Client Credential Flow - name: Customers description: Customer management and document upload operations - name: Balances description: Retrieve wallet balance information - name: Catalogue description: | A set of endpoints to retrieve contextual data to assemble requests to fin.com's API - name: Beneficiaries description: Manage beneficiary accounts for payments and transfers - name: Transactions description: Transaction history and management for beneficiaries - name: Virtual Accounts description: Create and manage virtual accounts for USD to USDC conversions - name: Fees & FX Rates description: Retrieve fees and foreign exchange rates paths: /v2/customers/{customer_id}/business/attach: post: tags: - Customers summary: Attach Documents to Business Customer V2 description: >- Attach formation, ownership, and supporting documents to an existing business customer. Documents are categorised into three arrays — formation_documents, ownership_documents, and supporting_documents — replacing the v1 ownership_structure / company_details / legal_presence structure. parameters: - name: customer_id in: path required: true schema: type: string format: uuid description: Unique identifier for the business customer example: ed54db74-7dbe-47d2-8ea0-c2bf2a9dda06 requestBody: required: true content: application/json: schema: $ref: '#/components/schemas/AttachDocumentsToBusinessCustomerV2Input' example: formation_documents: - type: EVIDENCE_OF_DIRECTORS_AND_CONTROLLERS description: Certificate of Incorporation files: - uri: /AbAcQ4hn_0652746727637.pdf - type: REGISTRATION_DOCUMENT description: Business registration doc files: - uri: /AbAcQ4hn_0652746727638.pdf ownership_documents: - type: PROOF_OF_SIGNATORY_AUTHORITY description: Shareholder Registry files: - uri: /XyZ123mn_0652746727639.pdf supporting_documents: - type: PROOF_OF_SOURCE_OF_FUNDS files: - uri: /PoAdef45_0652746727640.pdf - type: PROOF_OF_ADDRESS files: - uri: /PoAdef45_0652746727641.pdf tos_policies_value: 6955e70b-f9f3-4076-b1ce-5c897085dd24 responses: '200': description: Documents attached successfully content: application/json: schema: type: object properties: data: type: object description: Generic response object '400': description: Validation failed content: application/json: schema: type: object properties: status: type: integer example: 400 message: type: string example: Validation failed data: type: object additionalProperties: type: string '401': $ref: '#/components/responses/AuthenticationError' '404': $ref: '#/components/responses/NotFoundError' '422': $ref: '#/components/responses/ValidationError' security: - bearerAuth: [] components: schemas: AttachDocumentsToBusinessCustomerV2Input: type: object required: - tos_policies_value properties: formation_documents: type: array description: >- Documents proving the legal existence of the business (e.g., Certificate of Incorporation, Articles of Incorporation, Trust Agreement, Tax registration certificate). items: $ref: '#/components/schemas/V2FormationDocumentItem' ownership_documents: type: array description: >- Documents proving who controls and owns the business (e.g., Shareholder Register, Org Chart, Power of Attorney, Directors Registry). items: $ref: '#/components/schemas/V2OwnershipDocumentItem' supporting_documents: type: array description: >- Additional compliance and operational documents (e.g., Proof of Address, Proof of Source of Funds, AML Comfort Letter, Marketing Materials). items: $ref: '#/components/schemas/V2SupportingDocumentItem' tos_policies_value: type: string description: >- Parsed from the tos_policies_value query parameter in the tos_policies_url returned by POST /v2/customers/business. Signifies the customer has accepted the Terms of Service. example: f11e77c6-8dc0-4d4b-a3f2-ed84c8ccfc69 V2FormationDocumentItem: type: object required: - files properties: type: type: string enum: - REGISTRATION_DOCUMENT - CONSTITUTIONAL_DOCUMENT - FORMATION_DOCUMENT - PROOF_OF_TAX_IDENTIFICATION - EVIDENCE_OF_DIRECTORS_AND_CONTROLLERS description: Formation document type. example: REGISTRATION_DOCUMENT description: type: string description: Optional human-readable description of this specific document. example: Certificate of Incorporation files: type: array description: >- One or more file URIs obtained from [Upload Document](https://developer.fin.com/api-reference/customers/upload-document) endpoint. minItems: 1 items: type: object required: - uri properties: uri: type: string description: File URI returned by the upload endpoint. example: /AbAcQ4hn_0652746727639.pdf V2OwnershipDocumentItem: type: object required: - files properties: type: type: string enum: - OWNERSHIP_INFORMATION - OWNERSHIP_CHART - PROOF_OF_SIGNATORY_AUTHORITY description: Ownership document type. example: OWNERSHIP_INFORMATION description: type: string description: Optional human-readable description of this specific document. example: Ownership information document files: type: array description: >- One or more file URIs obtained from [Upload Document](https://developer.fin.com/api-reference/customers/upload-document) endpoint. minItems: 1 items: type: object required: - uri properties: uri: type: string description: File URI returned by the upload endpoint. example: /AbAcQ4hn_0652746727639.pdf V2SupportingDocumentItem: type: object required: - files properties: type: type: string enum: - SHAREHOLDER_REGISTER - PROOF_OF_NATURE_OF_BUSINESS - PROOF_OF_ENTITY_NAME_CHANGE - CERT_OF_INCUMBENCY - PROOF_OF_SOURCE_OF_FUNDS - PROOF_OF_SOURCE_OF_WEALTH - AML_COMFORT_LETTER - MARKETING_MATERIALS - TAX_EXEMPT_ENTITY_CONFIRMATION - E_SIGNATURE_CERTIFICATE - FLOW_OF_FUNDS - PROOF_OF_NATURE_OF_BUSINESS_LICENSE - PROOF_OF_NATURE_OF_BUSINESS_AML_POLICY - EVIDENCE_OF_GOOD_STANDING - PROOF_OF_ACCOUNT_PURPOSE - PROOF_OF_ADDRESS - OTHER description: Supporting document type. example: PROOF_OF_SOURCE_OF_FUNDS description: type: string description: Optional human-readable description of this specific document. example: Bank statements for the past 6 months files: type: array description: >- One or more file URIs obtained from [Upload Document](https://developer.fin.com/api-reference/customers/upload-document) endpoint. minItems: 1 items: type: object required: - uri properties: uri: type: string description: File URI returned by the upload endpoint. example: /AbAcQ4hn_0652746727639.pdf responses: AuthenticationError: description: Authentication failed due to invalid credentials content: application/json: schema: type: object properties: message: type: string example: Authentication failed NotFoundError: description: Resource not found content: application/json: schema: type: object properties: message: type: string example: Resource not found ValidationError: description: Failed due to a formatting error. content: application/json: schema: type: object required: - message properties: message: type: string errors: type: array items: type: object additionalProperties: type: string securitySchemes: bearerAuth: type: http scheme: bearer bearerFormat: JWT description: >- Bearer token authentication. Obtain token from [Issue a Token](https://developer.fin.com/api-reference/authentication/issue-a-token) endpoint ````