> ## Documentation Index > Fetch the complete documentation index at: https://dev.nickel.com/llms.txt > Use this file to discover all available pages before exploring further. # Apply a check deposit to a payment link > Applies money from a check you deposited into Nickel Banking to one of your payment links, marking it paid for that amount. The money is already in your account, so nothing moves: the application appears in the link's `externalPayments` with `nickelBankingTransferId` set, and in the deposit's `applications`. Undo it with [Void an external payment](/api-reference/payment-link/void-an-external-payment-on-a-payment-link). A deposit can be applied while it is still `PROCESSING`. If the bank later returns or rejects the check, Nickel voids its applications and the payment links reopen. Send an `externalReferenceId` to make the call safe to retry: a repeat with the same reference on the same payment link returns the application it made instead of applying the deposit again. ## OpenAPI ````yaml /nickel-api-docs.yaml post /nickelBanking/checkDeposits/{checkDepositId}/apply openapi: 3.0.3 info: title: Nickel API description: >- This is the specification for the Nickel Rest API. The API lets you programmatically interact with the Nickel server. It uses resource oriented URLs, accepts and returns JSON encoded payloads and uses standard HTTP response codes. It is not a direct API to move money, but instead allows you to interact with Nickel as you would on a web interface. termsOfService: https://www.nickel.com/terms-of-service contact: email: support@nickel.com license: name: Apache 2.0 url: https://www.apache.org/licenses/LICENSE-2.0.html version: 1.0.0 servers: - url: https://rest.staging.nickel.com description: Sandbox / Staging - url: https://rest.nickel.com description: Production security: - bearerAuth: [] tags: - name: Payment description: Payments from your customers to you - name: Disbursement description: Payouts made from Nickel to you - name: Payment Link description: A request for payment against an invoice - name: Customer description: A customer record to request payments against - name: Charge Authorization description: >- An authorization for your customer to allow you to charge their payment method directly - name: Webhook description: Create a webhook for nickel to send updates to - name: File description: A file you can use to attach to invoices or debit authorizations - name: Vendor description: Manage vendors for accounts payable - name: Bill description: Bills from vendors and bill payments - name: Bill Payment Method description: >- A merchant's payment methods used to pay bills (bank accounts and cards on file) - name: Vendor Delivery Method description: >- How a vendor receives funds — bank account (ACH), check mailing address, or international wire (SWIFT) details - name: Nickel Banking description: Your Nickel Banking accounts, debit cards, check deposits and transactions externalDocs: description: Find out more about Nickel url: https://nickel.com paths: /nickelBanking/checkDeposits/{checkDepositId}/apply: post: tags: - Nickel Banking summary: Apply a check deposit to a payment link description: >- Applies money from a check you deposited into Nickel Banking to one of your payment links, marking it paid for that amount. The money is already in your account, so nothing moves: the application appears in the link's `externalPayments` with `nickelBankingTransferId` set, and in the deposit's `applications`. Undo it with [Void an external payment](/api-reference/payment-link/void-an-external-payment-on-a-payment-link). A deposit can be applied while it is still `PROCESSING`. If the bank later returns or rejects the check, Nickel voids its applications and the payment links reopen. Send an `externalReferenceId` to make the call safe to retry: a repeat with the same reference on the same payment link returns the application it made instead of applying the deposit again. operationId: applyCheckDeposit parameters: - name: checkDepositId in: path description: The deposit's `id` from List check deposits or Deposit a check. required: true schema: type: string requestBody: required: true content: application/json: schema: $ref: '#/components/schemas/CheckDepositApplyRequest' responses: '200': description: The application and the re-derived payment link content: application/json: schema: $ref: '#/components/schemas/ExternalPaymentResponse' '400': description: >- Invalid input, or the deposit can't be applied: it was returned or rejected, the amount is more than it has left to apply or more than the payment link has left to pay, or the link is archived or a reusable payment link content: application/json: schema: $ref: '#/components/schemas/Error' '403': $ref: '#/components/responses/NickelBankingRefused' '404': description: The check deposit or the payment link was not found content: application/json: schema: $ref: '#/components/schemas/Error' '409': description: >- `externalReferenceId` is already used on this payment link for a different payment: another amount, another deposit, or money received outside Nickel (`code` is `REFERENCE_CONFLICT`). content: application/json: schema: $ref: '#/components/schemas/Error' '500': description: Internal server error content: application/json: schema: $ref: '#/components/schemas/Error' default: description: Unexpected error content: application/json: schema: $ref: '#/components/schemas/Error' components: schemas: CheckDepositApplyRequest: required: - paymentLinkId type: object properties: paymentLinkId: type: string description: The payment link the check pays. example: cmq7ab3cd000gsf02e5f6g7h8 amountCents: type: integer format: int64 minimum: 1 description: >- Cents to apply. Defaults to the smaller of the deposit's `unappliedAmountCents` and what the payment link has left to pay. example: 100000 externalReferenceId: type: string maxLength: 255 description: >- Your own id for this application. A repeat with the same id on the same payment link returns the existing application instead of applying the deposit again, and one that differs from it (another amount, another deposit, or money received outside Nickel) is a `409`. Voiding the application frees the id. example: apply_8f3a2c ExternalPaymentResponse: required: - externalPayment - paymentLink type: object properties: externalPayment: $ref: '#/components/schemas/ExternalPayment' paymentLink: $ref: '#/components/schemas/PaymentLink' Error: required: - error type: object properties: error: type: string description: >- A human-readable error message describing what went wrong. Note that some 500 responses may return a plain text string instead of this JSON object. code: type: string description: >- A stable machine-readable code, present on the errors a client can act on (e.g. `SHARED_ACCOUNT` on a 409 from the ACH debit authorization upload, `REFERENCE_CONFLICT` on a 409 from recording an external payment or a debit memo, `NICKEL_BANKING_NOT_ACTIVE` or `MISSING_PERMISSION` on a 403 from a Nickel Banking list). Absent otherwise. ExternalPayment: required: - id - amountCents - paidAt - voided type: object properties: id: type: string example: cmr9zx1bq000gsf02h1d5w4t8 amountCents: type: integer format: int64 example: 2500 paidAt: type: string format: date description: The date the money moved, as you stated it (YYYY-MM-DD). example: '2026-08-30' voided: type: boolean description: >- Whether the record has been voided. A voided record counts toward nothing and is not listed on the payment link; it is only returned by the void endpoint. example: false externalReferenceId: type: string nullable: true description: >- Your own id for this money, as passed when the record was created. Null when none was given (records made in the Nickel dashboard). example: txn_8f3a2c nickelBankingTransferId: type: string nullable: true description: >- Set when this record applies a check you deposited into Nickel Banking rather than money received outside Nickel: the deposit's `transferId`, as [List check deposits](/api-reference/nickel-banking/list-check-deposits) reports it. Null for money received outside Nickel. example: null PaymentLink: required: - id - name - status - url - payments - externalPayments - debitMemos - debitMemoAmountCents - requestedAmountCents - completedAmountCents type: object properties: id: type: string example: clkqzo2y1000cx9tfohoiodq1 requestedAmountCents: type: integer format: int64 description: The total the link asks for, including its live debit memos. example: 12055 name: type: string example: INV-123 dueDate: type: string format: date nullable: true status: type: string example: ACTIVE payments: type: array items: $ref: '#/components/schemas/Payment' externalPayments: type: array description: >- Live payments recorded against this link outside Nickel (a mailed check, cash). Voided records are omitted. They count toward completedAmountCents alongside payments. items: $ref: '#/components/schemas/ExternalPayment' debitMemos: type: array description: >- Live amounts added to this link after it was issued (an NSF fee, a finance charge), oldest first. Voided memos are omitted. They are included in requestedAmountCents. items: $ref: '#/components/schemas/DebitMemo' debitMemoAmountCents: type: integer format: int64 description: >- Sum of debitMemos. requestedAmountCents minus this is the link's own amount. example: 0 customerId: type: string description: >- ID of the customer the payment link belongs to. Omitted for links created in the dashboard without a customer. url: type: string format: uri example: https://nickel.nickelpayments.com/pay/Ahndhz completedAmountCents: type: integer format: int64 feePassthroughPercent: type: integer nullable: true description: >- Percent (0-100) of the card processing fee passed through to the payer for this payment link. null means no per-link override (the customer/organization setting applies). example: 100 creditCardEnabled: type: boolean nullable: true description: >- Whether the payer can pay this link by credit card. null means no per-link override (the organization setting applies). example: true achEnabled: type: boolean nullable: true description: >- Whether the payer can pay this link by ACH/bank transfer. null means no per-link override (the organization setting applies). example: true amountEditable: type: boolean description: Whether the payer can edit the payment amount at checkout. example: false Payment: type: object properties: id: type: string status: type: string example: SUCCEEDED fees: type: array items: $ref: '#/components/schemas/Fee' amountInCents: type: integer format: int64 example: 10000 chargedAmountInCents: type: integer format: int64 example: 10290 platformFeeInCents: type: integer format: int64 example: 290 paymentLinkId: type: string nullable: true paymentMethod: nullable: true allOf: - $ref: '#/components/schemas/PaymentMethod' disbursement: nullable: true allOf: - $ref: '#/components/schemas/Disbursement' refunds: type: array items: $ref: '#/components/schemas/Refund' createdAt: type: number estimatedDisbursementDate: type: string nullable: true DebitMemo: required: - id - amountCents - description - voided - createdAt type: object properties: id: type: string example: cmrb2k7w1000hsf02q8d9x3vn amountCents: type: integer format: int64 example: 3500 description: type: string description: Shown to your customer on the payment page next to the amount. example: Returned check fee voided: type: boolean description: >- Whether the memo has been voided. A voided memo counts toward nothing and is not listed on the payment link; it is only returned by the void endpoint. example: false externalReferenceId: type: string nullable: true description: Your own id for the memo, as passed when it was recorded. example: DM-1042 createdAt: type: string format: date-time Fee: type: object properties: type: type: string example: CREDIT_CARD_FEE amountInCents: type: integer format: int64 example: 290 PaymentMethod: type: object properties: id: type: string type: type: string enum: - ACH - Card - NickelBalance description: '`NickelBalance` is a Nickel Banking account.' achDetails: nullable: true allOf: - $ref: '#/components/schemas/ACHDetails' cardDetails: nullable: true allOf: - $ref: '#/components/schemas/CardDetails' nickelBalanceDetails: nullable: true description: Set when `type` is `NickelBalance`; null otherwise. allOf: - $ref: '#/components/schemas/NickelBalanceDetails' billingDetails: nullable: true allOf: - $ref: '#/components/schemas/BillingDetails' Disbursement: type: object properties: id: type: string status: type: string example: PENDING amountInCents: type: integer format: int64 example: 10000 bankName: type: string example: JP Morgan Chase accountNumberLastFour: type: string paymentIds: type: array items: type: string example: clkqzo2y1000cx9tfohoiodq1 createdAt: type: string format: date nullable: true paidAt: type: string format: date nullable: true Refund: type: object properties: id: type: string amountCents: type: integer format: int64 example: 515 refundDate: type: string format: date-time voided: type: boolean ACHDetails: type: object properties: bankName: type: string example: JP Morgan Chase routingNumber: type: string accountNumberLastFour: type: string CardDetails: type: object properties: brand: type: string nullable: true example: visa last4: type: string nullable: true holderName: type: string nullable: true expMonth: type: string nullable: true example: '2' expYear: type: string nullable: true example: '2030' NickelBalanceDetails: type: object description: The Nickel Banking account a `NickelBalance` payment method pays from. properties: nickname: type: string nullable: true description: The name you gave the account in the dashboard, if any. example: Operating accountNumberLastFour: type: string nullable: true example: '6789' spendableCents: type: integer format: int64 nullable: true description: >- What the account can pay right now, in cents — its available balance less money already committed to other payments. A bill payment larger than this fails. example: 125000 BillingDetails: type: object properties: name: type: string nullable: true companyName: type: string nullable: true street: type: string nullable: true city: type: string nullable: true state: type: string nullable: true zip: type: string nullable: true email: type: string nullable: true responses: NickelBankingRefused: description: >- Nickel Banking data this API key can't read. `code` is `NICKEL_BANKING_NOT_ACTIVE` when your organization has no active Nickel Banking account, or `MISSING_PERMISSION` when the team member the API key belongs to lacks the permission this list needs; the message names it. Also returned, without a `code`, for an API key without REST API access. content: application/json: schema: $ref: '#/components/schemas/Error' securitySchemes: bearerAuth: type: http scheme: bearer ````