> ## 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. # Create a Pay-in > Create a pay-in instruction for a customer. Make payment before expiry with mandatory reference code and receive crypto in the destination wallet address. Pay-in instructions require separate configuration. Contact support to enable this feature for your account. ## OpenAPI ````yaml POST /v2/transactions/pay-ins 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/transactions/pay-ins: post: tags: - Transactions summary: Create a Pay-in description: >- Create a pay-in instruction for a customer. Make payment before expiry with mandatory reference code and receive crypto in the destination wallet address. operationId: createPayInV2 parameters: - name: X-Idempotency-Key in: header required: true description: >- Unique key to safely retry the request without creating duplicate pay-ins. schema: type: string example: 0f0dcb34-4779-4468-858d-37086080769a requestBody: required: true content: application/json: schema: type: object required: - customer_id - amount - currency - destination properties: customer_id: type: string format: uuid description: ID of the customer the pay-in is created for. example: 34c62166-3e7a-436b-a2e3-338c4148a859 amount: type: integer description: >- Amount to collect in minor units (cents) of the source currency. example: 100101 currency: type: string enum: - MXN description: Source currency. Only MXN is supported. example: MXN destination: type: object required: - address - rail - currency properties: address: type: string description: Destination crypto wallet address. example: '0xD2Ba7d0DaBd36498df5906fC7B054Fa9EfA9843E' rail: type: string enum: - POLYGON - SOLANA description: Blockchain rail for the destination wallet. example: POLYGON currency: type: string enum: - USDC description: Destination currency. Only USDC is supported. example: USDC developer_fee: type: object description: Optional developer fee applied to the pay-in. properties: fixed: type: number description: Fixed developer fee in the source currency. example: 0 percentage: type: number description: Percentage developer fee applied to the amount. example: 0 example: customer_id: 34c62166-3e7a-436b-a2e3-338c4148a859 amount: 100101 currency: MXN destination: address: '0xD2Ba7d0DaBd36498df5906fC7B054Fa9EfA9843E' rail: POLYGON currency: USDC developer_fee: fixed: 0 percentage: 0 responses: '201': description: Pay-in instruction created successfully content: application/json: schema: type: object properties: data: type: object properties: id: type: string format: uuid description: Unique identifier for the pay-in. example: 728c95d3-8b1e-4497-b3da-f36bcc066d7d customer_id: type: string format: uuid description: ID of the customer the pay-in belongs to. example: 34c62166-3e7a-436b-a2e3-338c4148a859 status: type: string enum: - PENDING - PROCESSING - COMPLETED - EXPIRED - FAILED description: Current status of the pay-in. example: PENDING transaction_id: type: string format: uuid nullable: true description: >- ID of the resulting transaction once the pay-in is processed. Null until a transaction is created. example: null created_at: type: string format: date-time description: Timestamp at which the pay-in was created. example: '2026-06-09T18:27:35.468309Z' expire_at: type: string format: date-time description: >- Timestamp after which the pay-in can no longer be paid. example: '2026-06-10T18:27:35.437874Z' source_amount: type: integer description: Source amount in minor units (cents). example: 100101 source_amount_in_major: type: number description: Source amount in major units. example: 1001.01 currency: type: string description: Source currency. example: MXN destination: type: object properties: address: type: string example: '0xD2Ba7d0DaBd36498df5906fC7B054Fa9EfA9843E' currency: type: string example: USDC rail: type: string example: POLYGON fees: type: object properties: developer_fee: type: object properties: fixed: type: number example: 0 percentage: type: number example: 0 total_developer_fee: type: number example: 0 network_fee: type: number example: 0 conversion_fee: type: number example: 0 total_fee: type: number example: 0 destination_amount_in_major: type: number description: >- Amount the customer receives in the destination currency, in major units. USDC maintains 6 decimal precision. example: 1.153622 exchange_rate: type: number description: >- Exchange rate applied from source to destination currency. example: 17.462264 deposit_instruction: type: object properties: type: type: string enum: - BANK_DEPOSIT - CHECKOUT description: Type of deposit instruction returned. example: BANK_DEPOSIT bank_details: type: object nullable: true description: >- Bank deposit details. Populated when type is BANK_DEPOSIT. properties: account_holder_name: type: string example: FIN BU1 bank_name: type: string example: FINCO PAY bank_address: type: string nullable: true description: >- Single-string bank address. Served only when a value is present. example: null bank_address_details: type: object nullable: true description: >- Structured bank address. Served only when a value is present. properties: street: type: string example: 123 Main Street street_2: type: string nullable: true example: null city: type: string example: New York state: type: string nullable: true example: null postal_code: type: string example: '10001' country: type: string example: USA bank_routing_number: type: string nullable: true description: >- Bank routing number. Served only when a value is present. example: null bank_account_number: type: string description: Full CLABE account number. example: '734180000129991804' payment_rails: type: array items: type: string description: Payment rails available for the bank deposit. example: - SPEI bank_country: type: string example: MEX account_type: type: string nullable: true description: >- Account type. Served only when a value is present. example: centralizing bank_code: type: object description: Bank code identifying the account. properties: code: type: string description: Full CLABE account number. example: '734180000129991804' type: type: string enum: - CLABE - IBAN - SWIFT example: CLABE reference: type: string description: >- Mandatory reference code to include with the payment. example: 88ff4abb99e39499db661e1c97f0770fb1fb05c3 checkout_details: type: object nullable: true description: Checkout details. Populated when type is CHECKOUT. example: null example: data: id: 728c95d3-8b1e-4497-b3da-f36bcc066d7d customer_id: 34c62166-3e7a-436b-a2e3-338c4148a859 status: PENDING transaction_id: null created_at: '2026-06-09T18:27:35.468309Z' expire_at: '2026-06-10T18:27:35.437874Z' source_amount: 100101 source_amount_in_major: 1001.01 currency: MXN destination: address: '0xD2Ba7d0DaBd36498df5906fC7B054Fa9EfA9843E' rail: POLYGON currency: USDC fees: developer_fee: fixed: 0 percentage: 0 total_developer_fee: 0 network_fee: 0 conversion_fee: 0 total_fee: 0 destination_amount_in_major: 57.324182 exchange_rate: 17.462264 deposit_instruction: type: BANK_DEPOSIT bank_details: bank_name: FINCO PAY bank_address: null bank_address_details: null bank_routing_number: null bank_account_number: '734180000129991804' payment_rails: - SPEI bank_country: MEX account_type: centralizing bank_code: code: '734180000129991804' type: CLABE reference: 88ff4abb99e39499db661e1c97f0770fb1fb05c3 account_holder_name: FIN BU1 checkout_details: null '401': $ref: '#/components/responses/AuthenticationError' '422': $ref: '#/components/responses/ValidationError' security: - bearerAuth: [] components: responses: AuthenticationError: description: Authentication failed due to invalid credentials content: application/json: schema: type: object properties: message: type: string example: Authentication failed 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 ````