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Generate Invoice PDFs

Create professional invoice PDFs with line items, calculations, and your company branding.

Overview​

This recipe shows you how to:

  • Design an invoice template
  • Generate invoices with dynamic data
  • Handle multiple line items
  • Include calculated totals

The Invoice Template​

Create a template with these sections:

  • Company logo
  • Company name and address
  • Invoice number and date

Customer Info​

  • Customer name
  • Billing address
  • Contact information

Line Items Table​

  • Description
  • Quantity
  • Unit price
  • Line total

Summary​

  • Subtotal
  • Tax
  • Total due
  • Payment terms

Template Variables​

Define these variables in your template:

{
  "variables": [
    { "name": "invoiceNumber", "type": "string", "required": true },
    { "name": "invoiceDate", "type": "string", "required": true },
    { "name": "dueDate", "type": "string", "required": true },
    { "name": "customerName", "type": "string", "required": true },
    { "name": "customerAddress", "type": "string" },
    { "name": "customerEmail", "type": "string" },
    { "name": "lineItems", "type": "array", "required": true },
    { "name": "subtotal", "type": "number", "required": true },
    { "name": "taxRate", "type": "number" },
    { "name": "taxAmount", "type": "number" },
    { "name": "total", "type": "number", "required": true },
    { "name": "notes", "type": "string" }
  ]
}

Generate Invoice​

Node.js​

import { Rynko } from '@rynko/sdk';

const client = new Rynko({ apiKey: process.env.RYNKO_API_KEY });

async function generateInvoice(order) {
  // Calculate line items
  const lineItems = order.items.map(item => ({
    description: item.name,
    quantity: item.quantity,
    unitPrice: item.price,
    total: item.quantity * item.price
  }));

  // Calculate totals
  const subtotal = lineItems.reduce((sum, item) => sum + item.total, 0);
  const taxRate = 0.10; // 10% tax
  const taxAmount = subtotal * taxRate;
  const total = subtotal + taxAmount;

  // Generate invoice
  const result = await client.documents.generate({
    templateId: 'invoice-template',
    format: 'pdf',
    variables: {
      invoiceNumber: `INV-${order.id}`,
      invoiceDate: new Date().toLocaleDateString(),
      dueDate: getDueDate(30), // Net 30

      customerName: order.customer.name,
      customerAddress: formatAddress(order.customer.address),
      customerEmail: order.customer.email,

      lineItems,
      subtotal: subtotal.toFixed(2),
      taxRate: (taxRate * 100).toFixed(0) + '%',
      taxAmount: taxAmount.toFixed(2),
      total: total.toFixed(2),

      notes: 'Payment due within 30 days. Thank you for your business!'
    },
    filename: `invoice-${order.id}`
  });

  return result.downloadUrl;
}

function getDueDate(days) {
  const date = new Date();
  date.setDate(date.getDate() + days);
  return date.toLocaleDateString();
}

function formatAddress(addr) {
  return `${addr.street}\n${addr.city}, ${addr.state} ${addr.zip}`;
}

Python​

from rynko import Rynko
from datetime import datetime, timedelta

client = Rynko(api_key=os.environ['RYNKO_API_KEY'])

def generate_invoice(order):
    # Calculate line items
    line_items = [{
        'description': item['name'],
        'quantity': item['quantity'],
        'unitPrice': item['price'],
        'total': item['quantity'] * item['price']
    } for item in order['items']]

    # Calculate totals
    subtotal = sum(item['total'] for item in line_items)
    tax_rate = 0.10
    tax_amount = subtotal * tax_rate
    total = subtotal + tax_amount

    # Generate invoice
    result = client.documents.generate(
        template_id='invoice-template',
        format='pdf',
        variables={
            'invoiceNumber': f"INV-{order['id']}",
            'invoiceDate': datetime.now().strftime('%B %d, %Y'),
            'dueDate': (datetime.now() + timedelta(days=30)).strftime('%B %d, %Y'),

            'customerName': order['customer']['name'],
            'customerAddress': format_address(order['customer']['address']),
            'customerEmail': order['customer']['email'],

            'lineItems': line_items,
            'subtotal': f"{subtotal:.2f}",
            'taxRate': f"{tax_rate * 100:.0f}%",
            'taxAmount': f"{tax_amount:.2f}",
            'total': f"{total:.2f}",

            'notes': 'Payment due within 30 days. Thank you for your business!'
        },
        filename=f"invoice-{order['id']}"
    )

    return result['downloadUrl']

Batch Invoice Generation​

Generate all monthly invoices at once:

async function generateMonthlyInvoices(month, year) {
  const orders = await getOrdersForMonth(month, year);

  const documents = orders.map(order => {
    const lineItems = calculateLineItems(order);
    const { subtotal, taxAmount, total } = calculateTotals(lineItems);

    return {
      variables: {
        invoiceNumber: `INV-${month}${year}-${order.id}`,
        invoiceDate: new Date().toLocaleDateString(),
        dueDate: getDueDate(30),
        customerName: order.customer.name,
        customerAddress: formatAddress(order.customer.address),
        lineItems,
        subtotal: subtotal.toFixed(2),
        taxAmount: taxAmount.toFixed(2),
        total: total.toFixed(2)
      },
      filename: `invoice-${order.customer.name.toLowerCase().replace(/\s+/g, '-')}-${month}${year}`,
      metadata: {
        orderId: order.id,
        customerId: order.customer.id
      }
    };
  });

  const batch = await client.documents.generateBatch({
    templateId: 'invoice-template',
    format: 'pdf',
    documents
  });

  console.log(`Submitted ${documents.length} invoices. Batch ID: ${batch.batchId}`);

  return batch;
}

Template Design Tips​

1. Use a Clean Layout​

+------------------------------------------+
|  [LOGO]    INVOICE                       |
|            Invoice #: {{invoiceNumber}}  |
|            Date: {{invoiceDate}}         |
|            Due: {{dueDate}}              |
+------------------------------------------+
|  BILL TO:                                |
|  {{customerName}}                        |
|  {{customerAddress}}                     |
+------------------------------------------+
|  Description    Qty   Price    Total     |
|  {{#each lineItems}}                     |
|  {{description}} {{qty}} {{price}} {{total}}|
|  {{/each}}                               |
+------------------------------------------+
|                    Subtotal: {{subtotal}}|
|                    Tax:      {{taxAmount}}|
|                    TOTAL:    {{total}}   |
+------------------------------------------+
|  {{notes}}                               |
+------------------------------------------+

2. Format Currency Consistently​

Always format currency in your code before sending:

const formatCurrency = (amount) => {
  return new Intl.NumberFormat('en-US', {
    style: 'currency',
    currency: 'USD'
  }).format(amount);
};

variables: {
  subtotal: formatCurrency(subtotal),
  total: formatCurrency(total)
}

3. Handle Long Line Item Descriptions​

Use text wrapping in your template for long descriptions:

lineItems: items.map(item => ({
  description: item.name.substring(0, 50) + (item.name.length > 50 ? '...' : ''),
  // ... other fields
}))

Integration Examples​

After Payment (Stripe)​

// Stripe webhook handler
app.post('/webhooks/stripe', async (req, res) => {
  const event = req.body;

  if (event.type === 'payment_intent.succeeded') {
    const paymentIntent = event.data.object;
    const order = await getOrderByPaymentIntent(paymentIntent.id);

    // Generate invoice
    const invoiceUrl = await generateInvoice(order);

    // Save invoice URL
    await saveInvoiceUrl(order.id, invoiceUrl);

    // Optionally send via email service
    await sendInvoiceEmail(order.customer.email, invoiceUrl);
  }

  res.status(200).send('OK');
});

Scheduled Generation (Cron)​

// Run on the 1st of each month
cron.schedule('0 0 1 * *', async () => {
  const lastMonth = getLastMonth();
  await generateMonthlyInvoices(lastMonth.month, lastMonth.year);
});

Next Steps​