Create an internal account

Create a rule-based internal account.

A rule-based account is an additional account number for an account holder that already holds an account in the same currency. It carries a routing rule: every payment that settles into it is attributed to that account number and then swept to the rule’s destination, so you can issue one number per payer and reconcile incoming payments without matching on remittance text.

Only RULE_BASED accounts can be created here. INTERNAL_FIAT, INTERNAL_CRYPTO, and EMBEDDED_WALLET accounts are provisioned automatically when an account holder is created or approved.

The response carries the account’s own fundingPaymentInstructions — the routable number payers send to. Rule-based accounts are currently available in USD, for individual customers, and must be enabled for your platform before this endpoint accepts requests.

Sandbox platforms can create rule-based accounts and exercise the whole flow. The account number is generated locally rather than issued by a partner bank, and POST /sandbox/internal-accounts/{accountId}/fund stands in for a settled deposit — funding the account triggers its sweep just as a real deposit would.

Creating an account mints a new account number that cannot be reversed, so an Idempotency-Key header is required. A retry carrying the same key returns the account created by the first request with a 200 instead of a 201; reusing a key for a materially different account is rejected with 409.

POST /internal-accounts

cURL

externalDestination

curl --request POST \
  --url https://api.lightspark.com/grid/2025-10-13/internal-accounts \
  --header 'Authorization: Basic <encoded-value>' \
  --header 'Content-Type: application/json' \
  --header 'Idempotency-Key: <idempotency-key>' \
  --data '
{
  "customerId": "Customer:019542f5-b3e7-1d02-0000-000000000001",
  "type": "RULE_BASED",
  "currency": "USD",
  "label": "invoice-4417",
  "sweepRule": {
    "destination": {
      "accountId": "ExternalAccount:e85dcbd6-dced-4ec4-b756-3c3a9ea3d965",
      "paymentRail": "ACH"
    },
    "purposeOfPayment": "SELF",
    "description": "Rent sweep",
    "remittanceInformation": "Unit 4B March"
  }
}
'

200

{
  "id": "InternalAccount:12dcbd6-dced-4ec4-b756-3c3a9ea3d123",
  "type": "INTERNAL_FIAT",
  "status": "ACTIVE",
  "balance": {
    "amount": 12550,
    "currency": {
      "code": "USD",
      "name": "United States Dollar",
      "symbol": "$",
      "decimals": 2
    }
  },
  "totalBalance": {
    "amount": 12550,
    "currency": {
      "code": "USD",
      "name": "United States Dollar",
      "symbol": "$",
      "decimals": 2
    }
  },
  "fundingPaymentInstructions": [
    {
      "accountOrWalletInfo": {
        "accountType": "USD_ACCOUNT",
        "accountNumber": "1234567890",
        "routingNumber": "021000021",
        "bankName": "Chase Bank",
        "bankAccountType": "CHECKING",
        "intermediaryBankName": "JPMorgan Chase Bank",
        "intermediaryRoutingNumber": "021000021",
        "fiToFiInformation": "/BNF/Invoice 4471"
      },
      "instructionsNotes": "Please ensure the reference code is included in the payment memo/description field",
      "isPlatformAccount": true
    }
  ],
  "createdAt": "2025-10-03T12:30:00Z",
  "updatedAt": "2025-10-03T12:30:00Z",
  "customerId": "Customer:019542f5-b3e7-1d02-0000-000000000001",
  "label": "invoice-4417",
  "sweepRule": {
    "destination": {
      "accountId": "ExternalAccount:a12dcbd6-dced-4ec4-b756-3c3a9ea3d123",
      "paymentRail": "ACH"
    },
    "minimumAmount": {
      "amount": 12550,
      "currency": {
        "code": "USD",
        "name": "United States Dollar",
        "symbol": "$",
        "decimals": 2
      }
    },
    "maximumAmount": {
      "amount": 12550,
      "currency": {
        "code": "USD",
        "name": "United States Dollar",
        "symbol": "$",
        "decimals": 2
      }
    },
    "purposeOfPayment": "SELF",
    "description": "Rent sweep",
    "remittanceInformation": "Unit 4B March",
    "platformFeeOverride": {
      "platformFixedFee": {
        "amount": 50,
        "currency": "USD"
      },
      "platformVariableFeeBps": 30
    }
  },
  "privateEnabled": true,
  "cardCapabilities": {
    "supportsSpendLimits": true,
    "supportsTransactionCountLimit": true,
    "supports3dSecurePassword": false,
    "supportsPanReveal": true
  }
}

Authorizations

Authorization · string · header · required

API token authentication using format <api token id>:<api client secret>

Headers

Idempotency-Key · string · required

A unique identifier for the request. Required, because creating the account mints an account number that cannot be reversed. Retries must carry the same key.

Example:

"550e8400-e29b-41d4-a716-446655440000"

Body

application/json

Request body for POST /internal-accounts. Only RULE_BASED accounts can be created today, and they are rejected without a sweepRule — the type and its rule are created together or not at all.

type · enum<string> · required

Must be RULE_BASED. INTERNAL_FIAT, INTERNAL_CRYPTO, and EMBEDDED_WALLET accounts are provisioned automatically when a customer is created or approved, so they cannot be created through this endpoint.

Available options: INTERNAL_FIAT, INTERNAL_CRYPTO, EMBEDDED_WALLET, RULE_BASED

Example:

"RULE_BASED"

currency · string · required

Currency code the account is denominated in (ISO 4217). Rule-based accounts are currently available in USD only.

Example:

"USD"

customerId · string

The customer the account is created for. Omit it to create a platform-owned account. The account holder must already have a verified account in the same currency, which is where funds land when a sweep cannot be completed. Platform-owned rule-based accounts are not available yet, so omitting this is currently rejected.

Example:

"Customer:019542f5-b3e7-1d02-0000-000000000001"

label · string

Your own name for the account, echoed back on reads. Useful for identifying which payer the account was issued for.

Maximum string length: 255

Example:

"invoice-4417"

sweepRule · Sweep Rule Request · object

The routing rule for the account. Required when type is RULE_BASED, which is the only type this endpoint creates today: a rule-based account with no rule has no meaning, so the two are written together.

Show child attributes

Response

200

application/json

The Idempotency-Key was already used to create this account. The account created by the first request is returned unchanged.

id · string · required

The ID of the internal account

Example:

"InternalAccount:12dcbd6-dced-4ec4-b756-3c3a9ea3d123"

type · enum<string> · required

Classification of an internal account.

• INTERNAL_FIAT: A Grid-managed fiat holding account (for example, the USD holding account used as the source for Payouts flows).
• INTERNAL_CRYPTO: A Grid-managed crypto holding account denominated in a stablecoin such as USDC.
• EMBEDDED_WALLET: A self-custodial Embedded Wallet provisioned for the customer. Outbound transfers require a session signature produced by the customer's device — see the Embedded Wallets guide.
• RULE_BASED: An additional account number for an existing account holder, with a routing rule attached, so incoming payments can be attributed to a specific payer and swept automatically. Created with POST /internal-accounts.

Available options: INTERNAL_FIAT, INTERNAL_CRYPTO, EMBEDDED_WALLET, RULE_BASED

status · enum<string> · required

Status of a Grid internal account. The status determines whether the account can send or receive payments.

• PENDING: The account is under review and is being provisioned. The account cannot send or receive payments until provisioning completes.
• ACTIVE: The account is ready to send and receive payments.
• CLOSED: The account cannot send or receive payments. A customer can initiate the closing of an internal account, after which the account transitions to this status.
• FROZEN: The account cannot send or receive payments. Grid may freeze an account in response to compliance or fraud signals; payments are blocked while the account remains frozen.
• FAILED: The account could not be provisioned. Grid was unable to create the underlying account, so it cannot send or receive payments and requires remediation.

Available options: PENDING, ACTIVE, CLOSED, FROZEN, FAILED

Example:

"ACTIVE"

balance · object · required

The balance available to spend, excluding pending and held funds

Show child attributes

totalBalance · object · required

The total balance, including pending and held funds

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fundingPaymentInstructions · object[] · required

Payment instructions for funding the account

Show child attributes

createdAt · string<date-time> · required

Timestamp when the internal account was created

Example:

"2025-10-03T12:30:00Z"

updatedAt · string<date-time> · required

Timestamp when the internal account was last updated

Example:

"2025-10-03T12:30:00Z"

customerId · string

The ID of the customer associated with the internal account. If this field is empty, the internal account belongs to the platform.

Example:

"Customer:019542f5-b3e7-1d02-0000-000000000001"

label · string

The platform-supplied label recorded when the account was created. Null for accounts that carry none.

Maximum string length: 255

Example:

"invoice-4417"

sweepRule · Sweep Rule · object

The routing rule attached to this account. Null for accounts that carry no rule, which is every account other than a RULE_BASED one.

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privateEnabled · boolean

Whether wallet privacy is enabled for the Embedded Wallet. Only present for EMBEDDED_WALLET internal accounts.

Example:

true

cardCapabilities · object

Actions supported for a card issued now with this account as its funding source. They can change if the platform's card routing changes and do not describe cards already issued using the account. The funding source a create request supplies selects the issuer and therefore the resulting card's capabilities; read this field from that account. Absent when this account cannot fund a card.

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