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The Nessie API integration provides access to Capital One’s banking sandbox data. All endpoints are prefixed with /api/nessie.

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Authentication

Nessie API requires an API key configured in the NESSIE_API_KEY environment variable. The API key is automatically appended to all requests.

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Accounts

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Get Accounts by Customer

curl -X GET "http://localhost:3001/api/nessie/accounts?customerId=697541cf95150878eafea4ff"
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customerId
string
required
The Nessie customer ID to retrieve accounts for
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_id
string
Unique account identifier
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type
string
Account type: Checking, Savings, or Credit Card
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nickname
string
User-friendly account name
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rewards
number
Rewards points balance
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balance
number
Current account balance in dollars
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account_number
string
Account number
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customer_id
string
Associated customer ID

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Get Account by ID

curl -X GET "http://localhost:3001/api/nessie/accounts/697541cf95150878eafea500"

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Get Account Purchases

curl -X GET "http://localhost:3001/api/nessie/accounts/697541cf95150878eafea500/purchases"
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_id
string
Unique purchase identifier
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merchant_id
string
ID of the merchant where purchase was made
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medium
string
Payment medium: balance or rewards
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purchase_date
string
Date of purchase (YYYY-MM-DD)
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amount
number
Purchase amount in dollars
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status
string
Purchase status
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description
string
Optional purchase description

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Get Account Deposits

curl -X GET "http://localhost:3001/api/nessie/accounts/697541cf95150878eafea500/deposits"
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_id
string
Unique deposit identifier
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medium
string
Deposit medium: balance or rewards
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transaction_date
string
Date of deposit (YYYY-MM-DD)
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amount
number
Deposit amount in dollars
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status
string
Deposit status
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description
string
Optional deposit description

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Get Account Bills

curl -X GET "http://localhost:3001/api/nessie/accounts/697541cf95150878eafea500/bills"
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_id
string
Unique bill identifier
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status
string
Bill status: pending, recurring, completed, or cancelled
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payee
string
Bill payee name
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nickname
string
Optional bill nickname
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payment_date
string
Next payment date (YYYY-MM-DD)
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recurring_date
number
Day of month for recurring bills (1-31)
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payment_amount
number
Payment amount in dollars

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Get Account Loans

curl -X GET "http://localhost:3001/api/nessie/accounts/697541cf95150878eafea500/loans"
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_id
string
Unique loan identifier
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type
string
Loan type: home, auto, or small business
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status
string
Loan status: pending, approved, or declined
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credit_score
number
Credit score at time of application
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monthly_payment
number
Monthly payment amount in dollars
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amount
number
Total loan amount in dollars
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description
string
Optional loan description

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Customers

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Validate Customer

curl -X POST "http://localhost:3001/api/nessie/validate-customer" \
  -H "Content-Type: application/json" \
  -d '{"customerId": "697541cf95150878eafea4ff"}'
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customerId
string
required
Customer ID to validate
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valid
boolean
Whether the customer ID is valid
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customer
object
Customer details if valid
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customer._id
string
Customer identifier
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customer.first_name
string
Customer first name
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customer.last_name
string
Customer last name
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customer.address
object
Customer address details

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Get All Customers

curl -X GET "http://localhost:3001/api/nessie/customers"

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Get Customer by ID

curl -X GET "http://localhost:3001/api/nessie/customers/697541cf95150878eafea4ff"

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Get Customer Accounts

curl -X GET "http://localhost:3001/api/nessie/customers/697541cf95150878eafea4ff/accounts"

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Merchants

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Get All Merchants

curl -X GET "http://localhost:3001/api/nessie/merchants"

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Get Merchant by ID

curl -X GET "http://localhost:3001/api/nessie/merchants/697541cf95150878eafea520"

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Error Handling

All endpoints return standard HTTP status codes:
  • 200 OK - Request successful
  • 400 Bad Request - Missing or invalid parameters
  • 404 Not Found - Resource not found
  • 500 Internal Server Error - Server error
{
  "error": "customerId query parameter is required"
}

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