> ## Documentation Index > Fetch the complete documentation index at: https://docs.mnai.com/llms.txt > Use this file to discover all available pages before exploring further. # Send a Mock Deposit > Simulates an inbound deposit into a balance account through a given deposit instruction, so you can exercise downstream processing — balances, transactions, and webhooks — without moving real money. This is fire-and-acknowledge: it responds `202` with an empty body and settles out of band, so observe the result by polling the account balance or transactions. > **Sandbox only.** This endpoint exists exclusively in the sandbox environment for testing. Simulating a deposit is not possible in production. ## OpenAPI ````yaml /products/meridian-accounts/api-reference/meridian-accounts.json post /v1/accounts/{accountId}/simulate-deposit openapi: 3.1.1 info: title: Meridian API version: '1.0' description: API documentation for Meridian services contact: name: Meridian url: https://mnai.com email: support@mnai.com license: name: Proprietary url: https://mnai.com servers: - url: https://sandbox-api.va.meridianpay.com description: Sandbox - url: https://api.va.mnai.com description: Production security: [] paths: /v1/accounts/{accountId}/simulate-deposit: post: tags: - Sandbox summary: Send a Mock Deposit description: >- Simulates an inbound deposit into a balance account through a given deposit instruction, so you can exercise downstream processing — balances, transactions, and webhooks — without moving real money. This is fire-and-acknowledge: it responds `202` with an empty body and settles out of band, so observe the result by polling the account balance or transactions. > **Sandbox only.** This endpoint exists exclusively in the sandbox environment for testing. Simulating a deposit is not possible in production. operationId: simulateDeposit parameters: - name: Authorization in: header description: >- Bearer authentication header of the form `Bearer {token}`. Required for client-server (JWT) authentication. See [Authentication](/products/meridian-accounts/guides/authentication-overview). schema: type: string - name: X-Meridian-Program-Id in: header description: >- Identifies the program context for the request. Required for server-to-server (HMAC) authentication. See [Authentication](/products/meridian-accounts/guides/authentication-overview). schema: type: string - name: X-Meridian-User-Id in: header description: >- Identifies the Meridian user targeted by the request. Required for server-to-server (HMAC) authentication with MULTI_USER integrations; omit for SINGLE_USER. See [Authentication](/products/meridian-accounts/guides/authentication-overview). schema: type: string - name: X-Meridian-Api-Key in: header description: >- Partner API key issued by Meridian during provisioning. Required for server-to-server (HMAC) authentication. See [Authentication](/products/meridian-accounts/guides/authentication-overview). schema: type: string - name: X-Meridian-Timestamp in: header description: >- Current time in milliseconds since the Unix epoch. Must be within 60 seconds of the request. Required for server-to-server (HMAC) authentication. See [Authentication](/products/meridian-accounts/guides/authentication-overview). schema: type: string - name: X-Meridian-Signature in: header description: >- HMAC SHA-256 signature of the canonical request string, computed per request. Required for server-to-server (HMAC) authentication. See [Authentication](/products/meridian-accounts/guides/authentication-overview) for how to construct it. schema: type: string - name: accountId in: path description: >- ID of the balance account to deposit into — the `id` returned by `GET /v1/accounts` (e.g. `uspay-...`). required: true schema: type: string requestBody: description: The deposit instruction to credit and the amount to deposit. content: application/json: schema: $ref: '#/components/schemas/SimulateDepositApiRequest' examples: deposit_via_instruction: $ref: '#/components/examples/SimulateDepositViaDepositInstruction' required: true responses: '202': description: Deposit simulation accepted; settles out of band content: application/json: schema: $ref: '#/components/schemas/EmptyResponse' '400': description: Missing accountId or invalid request body (e.g. non-positive amount) content: application/json: schema: $ref: '#/components/schemas/MeridianError' '401': description: Missing or invalid authentication content: application/json: schema: $ref: '#/components/schemas/MeridianError' '403': description: >- The authenticated caller is not permitted: JWT scope missing, or the partner API key lacks entitlement, user ownership, or user-type match content: application/json: schema: $ref: '#/components/schemas/MeridianError' '404': description: >- The account was not found, or no deposit instruction exists on the account for the supplied `depositInstructionId`. content: application/json: schema: $ref: '#/components/schemas/MeridianError' security: - meridian-account-jwt: [] - partner-api-key: [] components: schemas: SimulateDepositApiRequest: type: object title: com.meridianpay.remittances.api.dto.meridian.SimulateDepositApiRequest required: - depositInstructionId - amount properties: depositInstructionId: type: string description: >- The `id` of the deposit instruction to credit — an opaque identifier such as `uspay-...`, NOT a rail name like `ACH` or `WIRE`. Each deposit instruction is a funding rail (ACH, Fedwire, etc.) configured on the account that an inbound deposit would arrive through. To find it, call `GET /v1/accounts/{accountId}` and copy the `id` of the desired entry from the `depositInstructions` array (match on its `rail.label`, e.g. `Fedwire` for a wire). Passing anything that is not an existing instruction id returns `404`. example: uspay-rvrsmt8vngju3kea5mm6fcck amount: type: string description: >- Amount to deposit, as a decimal string in the account's currency (e.g. `100.00`). Must be greater than zero. example: '100.00' EmptyResponse: type: object title: com.meridianpay.core.common.dto.EmptyResponse properties: message: type: - string - 'null' MeridianError: type: object title: com.meridianpay.core.common.api.MeridianError description: >- Represents an error response from the Meridian API, including validation errors and an optional error code. required: - message properties: validationErrors: type: array description: >- An array of validation errors that occurred during the processing of the request. This field is optional and may be empty if there are no validation errors. items: $ref: '#/components/schemas/ValidationError' errorCode: type: - string - 'null' description: >- An optional error code that provides additional information about the error. This field is optional and may be null. message: type: string description: >- A human-readable message describing the error. This field is required and should provide a clear explanation of the error that occurred. ValidationError: type: object title: com.meridianpay.core.common.api.ValidationError description: >- Represents a validation error that occurred during the processing of a request to the Meridian API. One of the following types of validation errors may be present: InvalidFormat, InvalidValue, MissingValue, UnprocessableValue, UnexpectedVerificationError, MissingRequestBody, MissingPathParameter, MissingQueryParameter, or NotFound. Each validation error includes a reference to the field that caused the error and a message describing the error. oneOf: - $ref: '#/components/schemas/InvalidFormat' - $ref: '#/components/schemas/InvalidValue' - $ref: '#/components/schemas/MissingPathParameter' - $ref: '#/components/schemas/MissingQueryParameter' - $ref: '#/components/schemas/MissingRequestBody' - $ref: '#/components/schemas/MissingValue' - $ref: '#/components/schemas/NotFound' - $ref: '#/components/schemas/UnexpectedVerificationError' - $ref: '#/components/schemas/UnprocessableValue' discriminator: propertyName: type mapping: com.meridianpay.core.common.api.ValidationError.InvalidFormat: $ref: '#/components/schemas/InvalidFormat' com.meridianpay.core.common.api.ValidationError.InvalidValue: $ref: '#/components/schemas/InvalidValue' com.meridianpay.core.common.api.ValidationError.MissingPathParameter: $ref: '#/components/schemas/MissingPathParameter' com.meridianpay.core.common.api.ValidationError.MissingQueryParameter: $ref: '#/components/schemas/MissingQueryParameter' com.meridianpay.core.common.api.ValidationError.MissingRequestBody: $ref: '#/components/schemas/MissingRequestBody' com.meridianpay.core.common.api.ValidationError.MissingValue: $ref: '#/components/schemas/MissingValue' com.meridianpay.core.common.api.ValidationError.NotFound: $ref: '#/components/schemas/NotFound' com.meridianpay.core.common.api.ValidationError.UnexpectedVerificationError: $ref: '#/components/schemas/UnexpectedVerificationError' com.meridianpay.core.common.api.ValidationError.UnprocessableValue: $ref: '#/components/schemas/UnprocessableValue' InvalidFormat: type: object title: com.meridianpay.core.common.api.ValidationError.InvalidFormat description: The provided value exists, but its format is invalid for the field. required: - fieldRef properties: fieldRef: type: string description: The field or parameter that triggered the validation error. message: type: string description: A human-readable explanation of the validation failure. InvalidValue: type: object title: com.meridianpay.core.common.api.ValidationError.InvalidValue description: >- The provided value is syntactically valid, but not accepted for the field. required: - fieldRef properties: fieldRef: type: string description: The field or parameter that triggered the validation error. message: type: string description: A human-readable explanation of the validation failure. MissingPathParameter: type: object title: com.meridianpay.core.common.api.ValidationError.MissingPathParameter description: A required path parameter was not supplied. required: - fieldRef properties: fieldRef: type: string description: The field or parameter that triggered the validation error. message: type: string description: A human-readable explanation of the validation failure. MissingQueryParameter: type: object title: com.meridianpay.core.common.api.ValidationError.MissingQueryParameter description: A required query parameter was not supplied. required: - fieldRef properties: fieldRef: type: string description: The field or parameter that triggered the validation error. message: type: string description: A human-readable explanation of the validation failure. MissingRequestBody: type: object title: com.meridianpay.core.common.api.ValidationError.MissingRequestBody description: >- The request body is missing or does not contain the required non-null fields. properties: message: type: string description: A human-readable explanation of the validation failure. fieldRef: type: string MissingValue: type: object title: com.meridianpay.core.common.api.ValidationError.MissingValue description: A required value for the field was not provided. required: - fieldRef properties: fieldRef: type: string description: The field or parameter that triggered the validation error. message: type: string description: A human-readable explanation of the validation failure. NotFound: type: object title: com.meridianpay.core.common.api.ValidationError.NotFound description: The referenced principal object was not found. required: - fieldRef properties: fieldRef: type: string description: The field or parameter that triggered the validation error. message: type: string description: A human-readable explanation of the validation failure. UnexpectedVerificationError: type: object title: >- com.meridianpay.core.common.api.ValidationError.UnexpectedVerificationError description: A downstream verification step failed while checking the value. required: - fieldRef properties: fieldRef: type: string description: The field or parameter that triggered the validation error. message: type: string description: A human-readable explanation of the validation failure. UnprocessableValue: type: object title: com.meridianpay.core.common.api.ValidationError.UnprocessableValue description: The provided value cannot be processed into a valid result. required: - fieldRef properties: fieldRef: type: string description: The field or parameter that triggered the validation error. message: type: string description: A human-readable explanation of the validation failure. examples: SimulateDepositViaDepositInstruction: value: depositInstructionId: uspay-deposit-instruction-id amount: '250.00' ````