---
title: "Incoming payment webhook and approval mechanism"
method: POST
path: "incoming-payment"
tags: ["Webhooks"]
---

# Incoming payment webhook and approval mechanism

`POST incoming-payment` (webhook)

Webhook that is called when an incoming payment is received by a customer's UMA address.
This endpoint should be implemented by clients of the Grid API.

### Authentication
The webhook includes a signature in the `X-Grid-Signature` header that allows you to verify that the webhook was sent by Grid.
To verify the signature:
1. Get the Grid public key provided to you during integration
2. Decode the base64 signature from the header
3. Create a SHA-256 hash of the request body
4. Verify the signature using the public key and the hash

If the signature verification succeeds, the webhook is authentic. If not, it should be rejected.

### Payment Approval Flow
When a transaction has `status: "PENDING"`, this webhook serves as an approval mechanism:

1. The client should check the `counterpartyInformation` against their requirements
2. To APPROVE the payment synchronously, return a 200 OK response
3. To REJECT the payment, return a 403 Forbidden response with an Error object
4. To request more information, return a 422 Unprocessable Entity with specific missing fields
5. To process the payment asynchronously, return a 202 Accepted response and then call the `/transactions/{transactionId}/approve` or `/transactions/{transactionId}/reject` endpoint within 5 seconds. Note that synchronous approval/rejection is preferred where possible.

The Grid system will proceed or cancel the payment based on your response.

For transactions with other statuses (COMPLETED, FAILED, REFUNDED), this webhook is purely informational.

## Payload

- IncomingPaymentWebhook
  - `id` string, required — Unique identifier for this webhook delivery (can be used for idempotency)
  - `type` 'INCOMING_PAYMENT.PENDING' | 'INCOMING_PAYMENT.COMPLETED' | 'INCOMING_PAYMENT.FAILED', required — Type of webhook event in OBJECT.EVENT dot-notation. The part before the dot identifies the resource, the part after identifies the event. This lets consumers route purely on type without inspecting data.status.
  - `timestamp` string, date-time, required — ISO 8601 timestamp of when the webhook was sent
  - `data` IncomingPaymentWebhookData, required
    - `id` string, required — Unique identifier for the transaction
    - `status` 'CREATED' | 'PENDING' | 'PROCESSING' | 'COMPLETED' | 'REJECTED' | 'FAILED' | 'REFUNDED' | 'EXPIRED', required — Status of a payment transaction. | Status | Description | |--------|-------------| | `CREATED` | Initial lookup has been created | | `PENDING` | Quote has been created | | `PROCESSING` | Funding has been received and payment initiated | | `COMPLETED` | Cross border payment has been received, converted and payment has been sent to the offramp network | | `REJECTED` | Receiving institution or wallet rejected payment, payment has been refunded | | `FAILED` | An error occurred during payment | | `REFUNDED` | Payment was unable to complete and refunded | | `EXPIRED` | Quote has expired |
    - `type` 'INCOMING', required — Type of transaction (incoming payment or outgoing payment)
    - `destination` union, required
      - AccountTransactionDestination — Destination account details
        - `destinationType` 'ACCOUNT', required
        - `accountId` string, required — Destination account identifier
      - UmaAddressTransactionDestination — UMA address destination details
        - `destinationType` 'UMA_ADDRESS', required
        - `umaAddress` string, required — UMA address of the recipient
    - `customerId` string, required — System ID of the customer (sender for outgoing, recipient for incoming)
    - `platformCustomerId` string, required — Platform-specific ID of the customer (sender for outgoing, recipient for incoming)
    - `settledAt` string, date-time — When the payment was or will be settled
    - `createdAt` string, date-time — When the transaction was created
    - `updatedAt` string, date-time — When the transaction was last updated
    - `agentId` string — If this transaction was initiated by an agent, the system-generated ID of that agent. Absent for platform-initiated transactions.
    - `description` string — Optional memo or description for the payment
    - `counterpartyInformation` CounterpartyInformation — Additional information about the counterparty, if available and relevant to the transaction and platform.
    - `source` union
      - AccountTransactionSource — Source account details
        - `sourceType` 'ACCOUNT', required
        - `accountId` string, required — Source account identifier
      - UmaAddressTransactionSource — UMA address source details
        - `sourceType` 'UMA_ADDRESS', required
        - `umaAddress` string, required — UMA address of the sender
      - RealtimeFundingTransactionSource — Transaction was funded using a real-time funding source (RTP, SEPA Instant, Spark, Stables, etc.).
        - `sourceType` 'REALTIME_FUNDING', required
        - `customerId` string — The customer on whose behalf the transaction was initiated.
        - `currency` string, required — Currency code for the funding source
    - `receivedAmount` CurrencyAmount, required
      - `amount` integer, required — Amount in the smallest unit of the currency (e.g., cents for USD/EUR, satoshis for BTC)
      - `currency` Currency, required
        - `code` string — Three-letter currency code (ISO 4217) for fiat currencies. Some cryptocurrencies may use their own ticker symbols (e.g. "BTC" for Bitcoin, "USDC" for USDC, etc.)
        - `name` string — Full name of the currency
        - `symbol` string — Symbol of the currency
        - `decimals` integer — Number of decimal places for the currency
    - `fees` integer — The total fees available from the receive quote in the smallest unit of the receiving currency (eg. cents).
    - `reconciliationInstructions` ReconciliationInstructions
      - `reference` string — Unique reference code to include with the payment to match it with the correct incoming transaction, when available.
      - `transactionHash` string — Transaction hash for the crypto transfer that delivered funds to the transaction destination, when available.
    - `rateDetails` IncomingRateDetails — Details about the rate and fees for an incoming transaction. Note: `gridApiFixedFee` is denominated in the receiving currency, so its equivalent value in the sending currency fluctuates with the FX rate. As a result, the total fee on a subsequent quote for the same transfer may differ even if the underlying fee structure is unchanged.
      - `gridApiMultiplier` number, double, required — The underlying multiplier from the mSATS to the receiving currency, including variable fees.
      - `gridApiFixedFee` integer, required — The fixed fee charged by the Grid product to execute the quote in the smallest unit of the receiving currency (eg. cents).
      - `gridApiVariableFeeRate` number, double, required — The variable fee rate charged by the Grid product to execute the quote as a percentage of the receiving currency amount.
      - `gridApiVariableFeeAmount` number, required — The variable fee amount charged by the Grid product to execute the quote in the smallest unit of the receiving currency (eg. cents). This is the receiving amount times gridApiVariableFeeRate.
    - `failureReason` 'LNURLP_FAILED' | 'PAY_REQUEST_FAILED' | 'PAYMENT_APPROVAL_WEBHOOK_ERROR' | 'PAYMENT_APPROVAL_TIMED_OUT' | 'OFFRAMP_FAILED' | 'MISSING_MANDATORY_PAYEE_DATA' | 'QUOTE_EXPIRED' | 'QUOTE_EXECUTION_FAILED' — Reason for failure of an incoming transaction. This is used to provide more context on why a transaction failed. If the transaction is not in a failed state, this field is omitted.
    - `requestedReceiverCustomerInfoFields` CounterpartyFieldDefinition[] — Information required by the sender's VASP about the recipient. Platform must provide these in the 200 OK response if approving. Note that this only includes fields which Grid does not already have from initial customer registration.
      - `name` 'FULL_NAME' | 'BIRTH_DATE' | 'NATIONALITY' | 'PHONE_NUMBER' | 'EMAIL' | 'POSTAL_ADDRESS' | 'TAX_ID' | 'REGISTRATION_NUMBER' | 'USER_TYPE' | 'COUNTRY_OF_RESIDENCE' | 'ACCOUNT_IDENTIFIER' | 'FI_LEGAL_ENTITY_NAME' | 'FI_ADDRESS' | 'PURPOSE_OF_PAYMENT' | 'ULTIMATE_INSTITUTION_COUNTRY' | 'IDENTIFIER' | 'BUSINESS_TYPE' | 'COMPANY_LEGAL_NAME', required — Name of a type of field containing info about a platform's customer or counterparty customer.
      - `mandatory` boolean, required — Whether the field is mandatory

## Acknowledgement `200`

Webhook received successfully.
For PENDING transactions, this indicates approval to proceed with the payment.
If `requestedReceiverCustomerInfoFields` were present in the webhook request, the corresponding fields for the recipient must be included in this response in the `receiverCustomerInfo` object.

- IncomingPaymentWebhookResponse
  - `receiverCustomerInfo` object — Information about the recipient, provided by the platform if requested in the webhook via `requestedReceiverCustomerInfoFields` and the payment is approved.

## Other responses

- `202` — Webhook received and will be processed asynchronously. The synchronous 200 response should be preferred where possible. This asycnhronous path should only be used in cases where the platform's architecture requires async (but still very quick) processing before approving or rejecting the payment. The platform must call the `/transactions/{transactionId}/approve` or `/transactions/{transactionId}/reject` endpoint to approve or reject the payment within 5 seconds or the payment will be automatically rejected.
- `400` — Bad request
- `401` — Unauthorized - Signature validation failed
- `403` — Forbidden - Payment rejected by the client. Only applicable for PENDING transactions.
- `409` — Conflict - Webhook has already been processed (duplicate id)
- `422` — Unprocessable Entity - Additional counterparty information required. Only applicable for PENDING transactions.

---

[API](https://skmtc.dev/lightsparkdev/apis/grid-api.md) · [All operations](https://skmtc.dev/lightsparkdev/apis/grid-api/llms.txt) · [OpenAPI document](https://skmtc-service-production.skmtc.workers.dev/v1/apis/lightsparkdev/grid-api/revisions/d0bce562bffd/schema)