HomeAPI Documentation

InvoicePig API

Name: Invoicepig Invoice Generator
Author: Invoicepig

Generate professional PDF invoices programmatically. Full customization with themes, custom labels, logos, and 52 supported currencies.

Get API Key Quick Start

Base URL

https://invoicepig.com/api/v1

Authentication

All API requests require authentication via an API key. Include your key in the request headers.

Header Authentication

x-api-key: ipig_live_xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

Or use the Authorization header with Bearer token:

Authorization: Bearer ipig_live_xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

Quick Start

Generate your first invoice in seconds with this simple example.

curl -X POST https://invoicepig.com/api/v1/invoices/generate \
  -H "x-api-key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "companyName": "Acme Corporation",
    "billTo": "John Doe\n123 Main Street\nNew York, NY 10001",
    "invoiceNumber": "INV-2025-001",
    "date": "2025-01-15",
    "currency": "USD",
    "theme": "Corporate",
    "lineItems": [
      {
        "description": "Web Development Services",
        "quantity": 40,
        "rate": 150
      },
      {
        "description": "UI/UX Design",
        "quantity": 20,
        "rate": 125
      }
    ]
  }' --output invoice.pdf

Rate Limits

API rate limits vary by subscription tier. Rate limit headers are included in all responses.

Free

100

invoices/month

10 req/min

Growth

1,000

invoices/month

50 req/min

Business

2,500

invoices/month

75 req/min

Pro

5,000

invoices/month

100 req/min

Enterprise

25,000

invoices/month

200 req/min

Rate Limit Headers

X-RateLimit-Limit: 50
X-RateLimit-Remaining: 49
X-RateLimit-Reset: 1705312800
X-Monthly-Usage: 45
X-Monthly-Limit: 1000

Generate Invoice

POST/api/v1/invoices/generateRequires API Key

Generate a PDF invoice from the provided data. Returns PDF binary by default, or base64 encoded string.

Preview Invoice

POST/api/v1/invoices/previewRequires API Key

Validate invoice data and preview calculated totals without generating a PDF. Does not count against monthly quota.

{
  "success": true,
  "data": {
    "valid": true,
    "preview": {
      "companyName": "Acme Corporation",
      "invoiceNumber": "INV-2025-001",
      "date": "2025-01-15",
      "currency": "USD",
      "currencySymbol": "$",
      "theme": "Corporate",
      "lineItemCount": 2,
      "financial": {
        "subtotal": 8500,
        "discount": 850,
        "tax": 650.25,
        "shipping": 25,
        "total": 8325.25,
        "amountPaid": 1000,
        "balanceDue": 7325.25
      },
      "hasWatermark": true
    }
  }
}

Themes

GET/api/v1/themes

List all available invoice themes with their color configurations.

{
  "success": true,
  "data": {
    "themes": [
      {
        "name": "Classic",
        "primaryColor": "#1e293b",
        "primaryColorDark": "#0f172a",
        "accentColor": "#14b8a6",
        "textColor": "#334155",
        "secondaryTextColor": "#64748b",
        "borderColor": "#e2e8f0",
        "backgroundColor": "#ffffff",
        "headerTextColor": "#ffffff",
        "description": "Traditional professional design with slate and teal accents"
      },
      // ... more themes
    ],
    "defaultTheme": "Classic"
  }
}

Custom Theme Colors

Instead of using a preset theme, you can provide custom colors:

{
  "customTheme": {
    "primaryColor": "#2563eb",
    "primaryColorDark": "#1e40af",
    "accentColor": "#3b82f6",
    "textColor": "#1e2937",
    "secondaryTextColor": "#64748b",
    "borderColor": "#e0e7ff",
    "backgroundColor": "#ffffff",
    "headerTextColor": "#ffffff"
  }
}

Currencies

GET/api/v1/currencies

List all 52 supported currencies with their symbols and names.

{
  "success": true,
  "data": {
    "currencies": [
      { "code": "USD", "symbol": "USD", "name": "US Dollar", "fullFormat": "USD (US Dollar)" },
      { "code": "EUR", "symbol": "EUR", "name": "Euro", "fullFormat": "EUR (Euro)" },
      { "code": "GBP", "symbol": "GBP", "name": "British Pound", "fullFormat": "GBP (British Pound)" },
      { "code": "JPY", "symbol": "JPY", "name": "Japanese Yen", "fullFormat": "JPY (Japanese Yen)" },
      // ... 48 more currencies
    ],
    "defaultCurrency": "USD"
  }
}

Custom Labels

GET/api/v1/labels/defaults

Get default label values for reference. Use these as a starting point for localization.

{
  "success": true,
  "data": {
    "labels": {
      "invoice": "INVOICE",
      "billTo": "Bill To",
      "shipTo": "Ship To",
      "invoiceNumber": "Invoice #",
      "date": "Date",
      "paymentTerms": "Payment Terms",
      "dueDate": "Due Date",
      "poNumber": "P.O. Number",
      "item": "Item",
      "hsCode": "HS Code",
      "quantity": "Qty",
      "rate": "Rate",
      "amount": "Amount",
      "subtotal": "Subtotal",
      "discount": "Discount",
      "tax": "Tax",
      "shipping": "Shipping",
      "total": "Total",
      "amountPaid": "Amount Paid",
      "balanceDue": "Balance Due",
      "notes": "Notes",
      "terms": "Terms & Conditions"
    }
  }
}

Localization Examples

Translate labels for different languages:

{
  "labels": {
    "invoice": "FACTURA",
    "billTo": "Facturar A",
    "date": "Fecha",
    "dueDate": "Fecha de Vencimiento",
    "total": "Total",
    "balanceDue": "Saldo Pendiente"
  }
}

Usage Statistics

GET/api/v1/usageRequires API Key

Get your current API usage statistics for the billing period.

{
  "success": true,
  "data": {
    "currentPeriod": {
      "start": "2025-01-01T00:00:00Z",
      "end": "2025-02-01T00:00:00Z"
    },
    "invoicesGenerated": 127,
    "invoicesLimit": 500,
    "invoicesRemaining": 373,
    "requestsToday": 1450,
    "rateLimitPerMinute": 30,
    "tier": "api_growth",
    "stats": {
      "totalRequests": 1450,
      "successfulRequests": 1445,
      "failedRequests": 5,
      "avgResponseTime": 245,
      "requestsByEndpoint": {
        "/api/v1/invoices/generate": 127,
        "/api/v1/invoices/preview": 450,
        "/api/v1/usage": 10
      }
    }
  }
}

Full Request Schema

Complete reference of all available request fields.

Error Codes

API errors follow a consistent format with error codes.

Code	HTTP Status	Description
`UNAUTHORIZED`	401	Missing or invalid API key
`FORBIDDEN`	403	API key doesn't have permission
`VALIDATION_ERROR`	400	Invalid request data
`RATE_LIMIT_EXCEEDED`	429	Too many requests
`MONTHLY_LIMIT_EXCEEDED`	429	Monthly quota exceeded
`INTERNAL_ERROR`	500	Server error

Error Response Format

{
  "success": false,
  "error": {
    "code": "VALIDATION_ERROR",
    "message": "Invalid request data",
    "details": [
      {
        "field": "lineItems[0].rate",
        "message": "Rate must be a positive number"
      },
      {
        "field": "date",
        "message": "Invalid date format. Use YYYY-MM-DD"
      }
    ]
  }
}

Ready to Get Started?

Create your API key and start generating professional invoices programmatically.

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