# Get invoice by ID

Retrieve a specific invoice by its unique identifier

This endpoint provides detailed invoice information including:
- Complete invoice details and line items
- Invoice status and payment tracking
- Client and project relationships
- Tax calculations and compliance data
- Payment history and outstanding balances
- Document generation and delivery status

Invoice Management Features:
- Invoice lifecycle tracking
- Payment status monitoring
- Tax calculation and compliance
- Client relationship integration
- Document generation and delivery

Invoice Details Include:
- Invoice number and reference
- Invoice status and payment status
- Client and project information
- Line items and amounts
- Tax calculations
- Payment history

Business Applications:
- Invoice status monitoring
- Payment tracking and reconciliation
- Client billing history
- Revenue recognition analysis
- Tax compliance reporting

Real Example:
bash
curl --location 'https://{{host}}/v1/invoice/45678' \
--header 'Authorization: bearer {{token}}' \
--header 'Content-Type: application/json'


Response Example:
json
{
  "id": 45678,
  "invoiceNumber": "INV-2024-001",
  "reference": "Q4-AUDIT-2024",
  "status": "SENT",
  "paymentStatus": "PARTIALLY_PAID",
  "clientId": 789,
  "clientName": "Acme Corporation",
  "clientEmail": "billing@acme.com",
  "projectId": 67890,
  "projectName": "Q4 Financial Audit",
  "issueDate": "2024-12-01T00:00:00Z",
  "dueDate": "2024-12-31T23:59:59Z",
  "subtotal": 20000.00,
  "taxAmount": 2000.00,
  "totalAmount": 22000.00,
  "currency": "USD",
  "paidAmount": 15000.00,
  "outstandingAmount": 7000.00,
  "lineItems": [
    {
      "id": 1,
      "description": "Financial Statement Audit",
      "quantity": 80,
      "unitPrice": 250.00,
      "amount": 20000.00,
      "taxRate": 0.10
    }
  ],
  "payments": [
    {
      "id": 12345,
      "amount": 15000.00,
      "paymentDate": "2024-12-15T10:30:00Z",
      "paymentMethod": "CREDIT_CARD",
      "status": "CONFIRMED"
    }
  ],
  "notes": "Payment due within 30 days of invoice date",
  "createdAt": "2024-12-01T09:00:00Z",
  "updatedAt": "2024-12-15T10:30:00Z"
}

Endpoint: GET /gql/v1/invoice/{id}
Version: 1.0.0
Security: BearerAuth

## Path parameters:

  - `id` (integer, required)
    Unique identifier of the invoice
    Example: 45678

## Response 200 fields (application/json):

  - `id` (integer)
    Unique invoice identifier
    Example: 45678

  - `invoiceNumber` (string)
    Invoice number
    Example: "INV-2024-001"

  - `reference` (string)
    Invoice reference or description
    Example: "Q4-AUDIT-2024"

  - `status` (string)
    Invoice status
    Enum: "DRAFT", "SENT", "VIEWED", "PAID", "OVERDUE", "CANCELLED"

  - `paymentStatus` (string)
    Payment status
    Enum: "UNPAID", "PARTIALLY_PAID", "PAID", "OVERDUE"

  - `clientId` (integer)
    Associated client identifier
    Example: 789

  - `clientName` (string)
    Client name
    Example: "Acme Corporation"

  - `clientEmail` (string)
    Client billing email
    Example: "billing@acme.com"

  - `projectId` (integer)
    Associated project identifier
    Example: 67890

  - `projectName` (string)
    Project name
    Example: "Q4 Financial Audit"

  - `issueDate` (string)
    Invoice issue date
    Example: "2024-12-01T00:00:00Z"

  - `dueDate` (string)
    Invoice due date
    Example: "2024-12-31T23:59:59Z"

  - `subtotal` (number)
    Invoice subtotal before tax
    Example: 20000

  - `taxAmount` (number)
    Total tax amount
    Example: 2000

  - `totalAmount` (number)
    Total invoice amount including tax
    Example: 22000

  - `currency` (string)
    Invoice currency code
    Example: "USD"

  - `paidAmount` (number)
    Total amount paid to date
    Example: 15000

  - `outstandingAmount` (number)
    Outstanding balance
    Example: 7000

  - `lineItems` (array)
    Invoice line items

  - `lineItems.id` (integer)
    Line item identifier
    Example: 1

  - `lineItems.description` (string)
    Line item description
    Example: "Financial Statement Audit"

  - `lineItems.quantity` (number)
    Quantity of units
    Example: 80

  - `lineItems.unitPrice` (number)
    Unit price
    Example: 250

  - `lineItems.amount` (number)
    Line item total amount
    Example: 20000

  - `lineItems.taxRate` (number)
    Tax rate applied
    Example: 0.1

  - `payments` (array)
    Payment history for this invoice

  - `payments.id` (integer)
    Payment identifier
    Example: 12345

  - `payments.amount` (number)
    Payment amount
    Example: 15000

  - `payments.paymentDate` (string)
    Payment date
    Example: "2024-12-15T10:30:00Z"

  - `payments.paymentMethod` (string)
    Payment method used
    Enum: "CREDIT_CARD", "DEBIT_CARD", "ACH", "BANK_TRANSFER", "CHECK", "WIRE", "PAYPAL"

  - `payments.status` (string)
    Payment status
    Enum: "PENDING", "CONFIRMED", "FAILED", "CANCELLED"

  - `notes` (string)
    Additional notes or terms
    Example: "Payment due within 30 days of invoice date"

  - `createdAt` (string)
    Invoice creation timestamp
    Example: "2024-12-01T09:00:00Z"

  - `updatedAt` (string)
    Last update timestamp
    Example: "2024-12-15T10:30:00Z"

## Response 404 fields (application/json):

  - `error` (string)
    Example: "Invoice not found"

  - `message` (string)
    Example: "Invoice with ID 45678 does not exist"


## Response 401 fields

## Response 403 fields

## Response 500 fields