# Get wallet balance

Retrieve the authenticated user's wallet balance for a specific currency. Returns 404 if the wallet does not exist. Requires a valid JWT access token.

Endpoint: GET /wallet/balance
Version: 0.1.0
Security: bearerAuth

## Query parameters:

  - `currency` (string, required)
    ISO currency code for the wallet
    Enum: "NGN", "USD"

## Response 200 fields (application/json):

  - `currency` (string, required)
    ISO currency code
    Example: "NGN"

  - `balanceAmountCents` (integer, required)
    Wallet balance in cents (smallest currency unit)

## Response 400 fields (application/json):

  - `error` (string, required)
    Error code
    Example: "VALIDATION_ERROR"

  - `message` (string, required)
    Human-readable error message
    Example: "Invalid email address or password format"

  - `details` (object)
    Additional error details (optional)

  - `requestId` (string)
    Unique request identifier for tracing (included in X-Request-ID header)
    Example: "550e8400-e29b-41d4-a716-446655440000"

  - `timestamp` (string, required)
    ISO 8601 timestamp when the error occurred
    Example: "2024-01-01T00:00:00Z"

## Response 401 fields (application/json):

  - `error` (string, required)
    Error code
    Example: "VALIDATION_ERROR"

  - `message` (string, required)
    Human-readable error message
    Example: "Invalid email address or password format"

  - `details` (object)
    Additional error details (optional)

  - `requestId` (string)
    Unique request identifier for tracing (included in X-Request-ID header)
    Example: "550e8400-e29b-41d4-a716-446655440000"

  - `timestamp` (string, required)
    ISO 8601 timestamp when the error occurred
    Example: "2024-01-01T00:00:00Z"

## Response 404 fields (application/json):

  - `error` (string, required)
    Error code
    Example: "VALIDATION_ERROR"

  - `message` (string, required)
    Human-readable error message
    Example: "Invalid email address or password format"

  - `details` (object)
    Additional error details (optional)

  - `requestId` (string)
    Unique request identifier for tracing (included in X-Request-ID header)
    Example: "550e8400-e29b-41d4-a716-446655440000"

  - `timestamp` (string, required)
    ISO 8601 timestamp when the error occurred
    Example: "2024-01-01T00:00:00Z"