> ## Documentation Index > Fetch the complete documentation index at: https://docs.onboard.xyz/llms.txt > Use this file to discover all available pages before exploring further. # Create Sub-account > This endpoint helps to create sub-accounts for a customer. The endpoint requires the main account ID to create a sub-account under it. Creates a new sub-account referenced by your internal identifier. ## OpenAPI ````yaml POST /ledger/subaccounts openapi: 3.0.3 info: version: 3.0.2 title: Onboard External API Gateway description: >- **Introduction** API Gateway for Onboard This specification describes API endpoints that are available to the public internet via the API gateway. The different endpoints require different authentication schemes, see documentation for what applies to the operation you want to access. **Errors** Uses conventional HTTP response codes to indicate success or failure. In general: - `2xx` status codes indicate success. Codes in the - `4xx` range indicate a client error (e.g. required parameters, failed request etc.). - `5xx` status codes indicate a server error occurred. contact: name: Nestcoin TechOps email: techops@nestcoin.com license: name: UNLICENSED servers: - url: https://external.dev.onboardpay.co description: Gateway for external API on staging environment. security: [] tags: - name: users-onboardapi description: Endpoints available to for merchants liquidity automation - name: users-users description: User related endpoints - name: users-partners description: Partner related endpoints - name: users-admin description: Back office related endpoints - name: users-user2fa description: User 2fa related endpoints - name: users-usernotifications description: User notifications related endpoints - name: users-merchantnetwork description: Merchant network endpoints - name: users-userauth description: Authentication endpoints - name: users-userservice description: Service endpoints - name: users-webhook description: webhook endpoints - name: users-config description: Configuration Endpoints paths: /ledger/subaccounts: post: tags: - ledger-sub-accounts summary: Create sub-account for a customer. description: > This endpoint helps to create sub-accounts for a customer. The endpoint requires the main account ID to create a sub-account under it. operationId: createSubAccount requestBody: description: Sub-account creation request required: true content: application/json: schema: $ref: '#/components/schemas/CreateSubAccountRequest' responses: '201': description: Sub-account created Successfully content: application/json: schema: $ref: '#/components/schemas/SubAccount' '400': $ref: '#/components/responses/LedgerSvcInvalidRequest' '401': $ref: '#/components/responses/LedgerSvcUnauthorized' '403': $ref: '#/components/responses/LedgerSvcAccessDenied' '404': $ref: '#/components/responses/LedgerSvcNotFound' default: $ref: '#/components/responses/LedgerSvcServerError' security: - HMACAuth: [] components: schemas: CreateSubAccountRequest: type: object description: | Request to create a sub-account under a main account. required: - accountId - reference properties: accountId: type: string format: uuid description: The main account ID under which the sub-account will be created. reference: type: string description: >- A unique reference for the sub-account. This must be unique across all sub-accounts. minLength: 6 maxLength: 36 pattern: ^[a-zA-Z0-9_-]{6,36}$ displayName: type: string description: An optional name for the sub-account. x-source-svc: ledger SubAccount: type: object additionalProperties: false required: - id - accountId - reference - accountBalance - currency - frozen - createdDate properties: id: type: string format: uuid description: Unique sub-account ID accountId: type: string format: uuid description: The main account ID to which this sub-account belongs. displayName: type: string description: An optional name for the sub-account. reference: type: string description: A unique reference for the sub-account. currency: type: string description: Currency of the sub-account example: USD accountBalance: $ref: '#/components/schemas/AccountBalanceDetails' frozen: type: boolean description: Indicates if the sub-account is frozen (locked) or not. default: false createdDate: type: string format: date-time description: The date the sub-account was created. x-source-svc: ledger AccountBalanceDetails: type: object additionalProperties: false description: Account balance details properties: balance: description: The actual ledger balance of the account type: number example: 1000 availableBalance: description: The available balance for spending type: number example: 1000 x-source-svc: ledger ErrorMessageDto: description: >- Default error object for services. This gives consistent error object that all services may use. type: object required: - code - message properties: code: type: string description: Error code example: UNKNOWN_ERROR message: type: string description: Descriptive error message example: Request could not be completed due to an error data: type: object description: Additional data for this error message. additionalProperties: true properties: {} x-common-model: ErrorMessageDto responses: LedgerSvcInvalidRequest: description: Request could not be validated content: application/json: schema: $ref: '#/components/schemas/ErrorMessageDto' example: code: BAD_REQUEST message: Request could not be validated. LedgerSvcUnauthorized: description: Client is not authorized to make request content: application/json: schema: $ref: '#/components/schemas/ErrorMessageDto' example: code: UNAUTHORIZED message: Either client security header is missing or it is not valid. LedgerSvcAccessDenied: description: Expected permission is not available. content: application/json: schema: $ref: '#/components/schemas/ErrorMessageDto' example: code: ACCESS_DENIED message: Expected permission or scope is not present. LedgerSvcNotFound: description: Entity was not found content: application/json: schema: $ref: '#/components/schemas/ErrorMessageDto' example: code: NOT_FOUND message: Information could not be found LedgerSvcServerError: description: Internal Server Error content: application/json: schema: $ref: '#/components/schemas/ErrorMessageDto' example: code: INTERNAL_ERROR message: An internal server error occurred. securitySchemes: HMACAuth: type: apiKey name: x-api-key in: header description: |- Requires authentication via API key and HMAC signature. * `x-api-key`: Your API key generated from your Onboard Business dashboard. * `x-timestamp`: Unix epoch timestamp (seconds) used in signature, allowed skew is 30 seconds * `x-signature`: SHA256 HMAC HEX signature calculated over `t={x-timestamp}&{requestBody}` using your API Secret. ````