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InvoiceTemplateGen

REST API · v1

Generate invoices from your own code

Send JSON, get back a print-ready PDF or a UBL 2.1 XML e-invoice. The same engine that powers our editor, ready for your app, CRM or billing system.

Get an API key View endpoints

Authentication

API access is included in the Pro plan. Generate a key on your account page. Send it as a bearer token with every request:

Authorization: Bearer YOUR_API_KEY

Endpoints

POST https://www.invoicetemplategen.com/api/v1/documents/pdf/

Returns application/pdf — the rendered document.

curl -X POST https://www.invoicetemplategen.com/api/v1/documents/pdf/ \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Accept: application/json" \
  -d @invoice.json -o invoice.pdf
POST https://www.invoicetemplategen.com/api/v1/documents/ubl/

Returns application/xml — a UBL 2.1 Invoice (or CreditNote for credit-note types).

curl -X POST https://www.invoicetemplategen.com/api/v1/documents/ubl/ \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Accept: application/json" \
  -d @invoice.json -o invoice.xml
POST https://www.invoicetemplategen.com/api/v1/documents/totals/

Returns JSON with subtotal, discount, tax, shipping, total and balance due.

curl -X POST https://www.invoicetemplategen.com/api/v1/documents/totals/ \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Accept: application/json" \
  -d @invoice.json

Request body

All fields are optional except type. Totals are always calculated for you.

FieldTypeDescription
type string Document type slug: invoice, quote, estimate, receipt, proforma-invoice, credit-note, purchase-order, sales-order, timesheet, work-order, account-statement, packing-slip
template string modern, classic or minimal
accent string Hex colour, e.g. #148a79
currency string ISO 4217 code, e.g. USD, EUR, GBP
logo string Base64 data URI (PNG/JPG/WebP), max ~1 MB
from / bill_to / ship_to string Multi-line address blocks; the first line is the party name
number, po_number, payment_terms string Free text
date, due_date date YYYY-MM-DD
items[] array Objects with description, quantity, rate
discount, tax number Combined with discount_type / tax_type: percent (default) or flat
tax_label string e.g. VAT, GST, Sales Tax
shipping, amount_paid number Flat amounts
notes, terms string Footer text
labels object Override any label, e.g. {"title": "TAX INVOICE"}

Example invoice.json

{
    "type": "invoice",
    "template": "modern",
    "accent": "#148a79",
    "currency": "USD",
    "number": "INV-0042",
    "date": "2026-10-19",
    "due_date": "2026-11-18",
    "payment_terms": "Net 30",
    "from": "Acme Studio\n12 Market Street\nSpringfield",
    "bill_to": "Globex Corp\n500 Industrial Way\nShelbyville",
    "items": [
        {
            "description": "Website design",
            "quantity": 1,
            "rate": 2400
        },
        {
            "description": "Hosting (12 months)",
            "quantity": 12,
            "rate": 25
        }
    ],
    "tax": 8.5,
    "tax_label": "Sales Tax",
    "discount": 10,
    "discount_type": "percent",
    "notes": "Thank you for your business!"
}

Errors & limits

  • 401 — missing or invalid API key.
  • 422 — validation failed; the response lists an errors object keyed by field.
  • 429 — rate limit exceeded (60 requests per minute per key).