Invoice Generator API

We created a simple API at Invoice-Generator.com to generate invoice PDFs on the fly. This service has been used internally by us for some time. We believe this could be helpful in your project as well.

The API has a primary endpoint that returns a PDF given details of an invoice. We don't store any of your invoice data.

In addition to PDF, the API can also generate e-invoices in UBL (Universal Business Language) with the invoice PDF embedded. This is useful as the world shifts to e-invoicing because UBL invoices are tricky to generate.

Use Cases

• Creating invoices for VAT compliance
• Generate a PDF of an invoice that you have the details to (recipient, line items, etc)
• Produce invoices for B2B buyers from an order or receipt
• Selling products or services on credit terms
• Creating e-invoices in UBL (Universal Business Language)

Table of Contents

• Getting Started
• Examples
  • Simple Invoice
  • JSON Input
  • VAT Invoice
  • Localization
  • Custom Fields
  • E-invoice
  • Sample Projects
• API Reference
  • Create Invoice PDF
  • Create E-invoice
• Support

Getting Started

In order to begin using the Invoice-Generator.com API, you first need to create an API key. The process for obtaining an API key is as follows.

1. Create a free Invoice-Generator.com account here, or sign in if you already have one.
2. Go to the Settings page.
3. In the "API Keys" section, click New API Key.

Now you have an API key and are ready to start invoicing!

Examples

Simple Invoice

curl https://invoice-generator.com \
  -H "Authorization: Bearer myApiKey" \
  -d from="Nikolaus Ltd" \
  -d to="Acme, Corp." \
  -d logo="https://example.com/img/logo-invoice.png" \
  -d number=1 \
  -d date="Feb 9, 2015" \
  -d due_date="Feb 16, 2015" \
  -d "items[0][name]"="Starter plan monthly" \
  -d "items[0][quantity]"=1 \
  -d "items[0][unit_cost]"=99 \
  -d notes="Thanks for being an awesome customer\!" \
  -d terms="Please pay by the due date." \
> invoice.pdf

VAT Invoice

Here's a simple cURL example for generating invoices with VAT:

curl https://invoice-generator.com \
  -H "Authorization: Bearer myApiKey" \
  -d from="Nikolaus Ltd%0AVAT ID: 1234" \
  -d to="Foster Moen%0AVAT ID: 4567" \
  -d logo="https://example.com/img/logo-invoice.png" \
  -d number=1 \
  -d date="Feb 9, 2015" \
  -d payment_terms="Charged - Do Not Pay" \
  -d "items[0][name]"="Starter Plan Monthly" \
  -d "items[0][quantity]"=1 \
  -d "items[0][unit_cost]"=99 \
  -d tax_title="VAT" \
  -d "fields[tax]"="%" \
  -d tax=8 \
  -d notes="Thanks for being an awesome customer\!" \
  -d terms="No need to submit payment. You will be auto-billed for this invoice." \
> invoice.vat.pdf

JSON Input

JSON input is also accepted with the Content-Type header set to application/json

curl https://invoice-generator.com \
  -H "Authorization: Bearer myApiKey" \
  -H "Content-Type: application/json" \
  -d '{"from":"Nikolaus Ltd","to":"Acme, Corp.","logo":"https://example.com/img/logo-invoice.png","number":1,"items":[{"name":"Starter plan","quantity":1,"unit_cost":99}],"notes":"Thanks for your business!"}' \
> invoice.pdf

Localization

It is possible to change the localization used to generate the invoice by supplying a locale in the Accept-Language header. The default locale is en-US.

curl https://invoice-generator.com \
  -H "Authorization: Bearer myApiKey" \
  -H "Accept-Language: fr-FR" \
  -d from="Nikolaus Ltd" \
  -d to="Acme Corp." \
  -d logo="https://example.com/img/logo-invoice.png" \
  -d number=1 \
  -d currency=eur \
  -d date="Feb 9, 2015" \
  -d due_date="Feb 16, 2015" \
  -d "items[0][name]"="Starter plan monthly" \
  -d "items[0][quantity]"=1 \
  -d "items[0][unit_cost]"=99 \
> invoice.pdf

Supported Languages

We currently have translations available in English, French, German, Spanish, and Thai.

Custom Fields

curl https://invoice-generator.com \
  -H "Authorization: Bearer myApiKey" \
  -d from="Nikolaus Ltd" \
  -d to="My Customer" \
  -d ship_to="Shipping Address" \
  -d logo="https://example.com/img/logo-invoice.png" \
  -d number=1 \
  -d date="Feb 9, 2015" \
  -d "custom_fields[0][name]"="My Custom Field" \
  -d "custom_fields[0][value]"="Some Value" \
  -d "items[0][name]"="Starter Plan Monthly" \
  -d "items[0][quantity]"=1 \
  -d "items[0][unit_cost]"=99 \
> invoice.custom_fields.pdf

E-invoice

Here's a simple cURL example for generating e-invoices in UBL XML:

curl https://invoice-generator.com/ubl \
  -H "Authorization: Bearer myApiKey" \
  -d from="Nikolaus Ltd%0AVAT ID: 1234" \
  -d to="Foster Moen%0AVAT ID: 4567" \
  -d logo="https://example.com/img/logo-invoice.png" \
  -d number=1 \
  -d date="Feb 9, 2015" \
  -d date="Mar 9, 2015" \
  -d payment_terms="NET 30" \
  -d "items[0][name]"="Starter Plan Monthly" \
  -d "items[0][quantity]"=1 \
  -d "items[0][unit_cost]"=99 \
  -d tax_title="VAT" \
  -d "fields[tax]"="%" \
  -d tax=8 \
  -d notes="Thanks for being an awesome customer\!" \
> invoice.xml

Sample Projects

• Go: generate invoices programmatically
• Ruby: generate invoices from Stripe webhooks
• Node.js: invoice-generator.js
• Python: python-invoice-generator

---

API Reference

Create Invoice PDF

POST https://invoice-generator.com

Invoice Parameters

When a value is null or zero, the field will not be shown on the invoice. The exception to this are the required fields from, to, date, and items.

Parameter	Description	Default Value
logo	URL of your logo	null
from	Your organization billing address and contact info	null
to	Entity being billed - multiple lines ok	null
ship_to	Shipping address - multiple lines ok	null
number	Invoice number	null
currency	ISO 4217 3-digit currency code	USD
custom_fields	Array of objects - see Custom Fields below	[]
date	Invoice date	current date
payment_terms	Payment terms summary (i.e. NET 30)	null
due_date	Invoice due date	null
items	Array of objects - see Line Items below	[]
fields	Object - see Subtotal Lines below	{"tax":"%","discounts":false,"shipping":false}
discounts	Subtotal discounts - numbers only	0
tax	Tax - numbers only	0
shipping	Shipping - numbers only	0
amount_paid	Amount paid - numbers only	0
notes	Notes - any extra information not included elsewhere	null
terms	Terms and conditions - all the details	null

Line Item Parameters

Line items are represented as an array of objects. Here's an example:

{
  "items": [
    {
      "name": "Gizmo",
      "quantity": 10,
      "unit_cost": 99.99,
      "description": "The best gizmos there are around."
    },
    {
      "name": "Gizmo v2",
      "quantity": 5,
      "unit_cost": 199.99
    }
  ]
}

Subtotal Line Parameters

The fields object toggles the discounts, tax, and shipping subtotal lines. Each setting can have a value of %, true, or false. For example to add a percent tax rate and flat shipping to your invoice you would send this:

{
  "fields": {
    "tax": "%",
    "discounts": false,
    "shipping": true
  },
  "tax": 7,
  "shipping": 15
}

Custom Field Parameters

Custom fields allow you to add additional fields to the invoice details in the top-right. Here's an example:

{
  "custom_fields": [
    {
      "name": "Gizmo",
      "value": "PO-1234"
    },
    {
      "name": "Account Number",
      "value": "CUST-456"
    }
  ]
}

Invoice Template Parameters

These parameters control the titles of the fields on the invoice template. If localization is used, the default values are translated to the specified language. Any invoice template parameter given will override the localized default.

Parameter	Default Value
header	INVOICE
to_title	Bill To
ship_to_title	Ship To
invoice_number_title	#
date_title	Date
payment_terms_title	Payment Terms
due_date_title	Due Date
purchase_order_title	Purchase Order
quantity_header	Quantity
item_header	Item
unit_cost_header	Rate
amount_header	Amount
subtotal_title	Subtotal
discounts_title	Discounts
tax_title	Tax
shipping_title	Shipping
total_title	Total
amount_paid_title	Amount Paid
balance_title	Balance
terms_title	Terms
notes_title	Notes

Create E-invoice

POST https://invoice-generator.com/ubl

Parameters

Creating an invoice with universal business language uses the same parameters as the Create Invoice PDF endpoint.

Support

Have a feature request or bug report? We would love to hear your thoughts! You can create an issue on GitHub for any issues you encounter or feature requests.

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