Invoice API

Invoice generator API for developers

A simple REST API to create, render, and email professional PDF invoices. Drop it into your SaaS billing, marketplace payouts, or any backend that needs invoices — without rebuilding tax math, layout, or i18n yourself.

Read the API docs Try the UI first

One request → one PDF invoice

POST a JSON body, get back a hosted PDF URL plus the raw bytes. No template engine to wire up, no headless Chrome to babysit.

curl
curl https://api.invoicecat.com/v1/invoices \
  -H "Authorization: Bearer $INVOICECAT_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "currency": "USD",
    "issue_date": "2026-05-03",
    "due_date":   "2026-06-02",
    "from": { "name": "Acme Studio", "email": "[email protected]" },
    "to":   { "name": "Globex Corp", "email": "[email protected]" },
    "items": [
      { "description": "Design retainer — May",
        "quantity": 1, "unit_price": 4500 }
    ],
    "tax_rate": 0.1,
    "notes": "Net 30. Wire transfer details on page 2."
  }'

Returns { id, number, pdf_url, total, status }. Same payload renders in 7 languages via the locale field.

What the API handles for you

PDF rendering

Pixel-perfect PDFs in A4, US Letter, or thermal-printer sizes. No headless Chrome on your servers.

Multi-currency

Render in 150+ ISO currencies with locale-aware decimal/thousand separators.

7 language templates

English, Japanese, Simplified & Traditional Chinese, Korean, Spanish, Russian — built in.

Tax engine

Per-line and invoice-level VAT, GST, and sales tax with inclusive/exclusive modes.

Custom branding

Upload a logo, set brand color, and pick from clean default templates.

Email delivery

Optionally have us deliver the PDF to the customer via SMTP/SendGrid with tracking.

Webhooks

invoice.created, invoice.paid, invoice.overdue events to keep your billing system in sync.

Numbering control

Auto-increment per series (INV-2026-0042) or pass your own number from your DB.

Idempotency keys

Safe retries — no duplicate invoices when the network blips between you and us.

Common use cases

Whenever your product creates a charge but Stripe Invoicing is too rigid or too expensive, the InvoiceCat API slots in.

SaaS billing receipts

Generate a polished invoice every time Stripe charges a card so EU/JP customers can file the right tax document.

Marketplace payouts

Issue per-vendor invoices for each weekly payout cycle — branded with the marketplace, not Stripe.

Internal tooling

Replace the Excel-and-DocuSign workflow your operations team uses to bill agency clients.

White-label apps

Embed invoice generation into your vertical SaaS without telling customers it is powered by a third party.

Why an API instead of building it yourself?

Roll your ownStripe InvoicingInvoiceCat API
Time to ship2–8 weeks1–2 daysUnder an hour
PDF qualityDepends on your CSS skillsPlain & rigidDesigned templates
Multi-languageYou translate everythingEN/EU mostly7 languages built-in
Custom brandingAnythingLimitedLogo, color, layout
Cost at low volumeEngineering hoursFree up to a pointFree tier + low per-invoice
Plays nicely withWhatever you wireStripe productsStripe / Paddle / your DB

Frequently asked questions

Do I need to use Stripe to use this API?
No. The InvoiceCat API is payment-agnostic. You call us when you want a PDF invoice; how money moves is up to you. We can also surface Stripe payment links on the invoice if you want to.
Can I use this as a free invoice generator API?
Yes. The free tier covers small volumes and unlimited test mode. Paid plans kick in once you cross the monthly invoice threshold or want webhooks, custom branding, or email delivery.
How is this different from Stripe Invoicing?
Stripe Invoicing is great if you already live inside Stripe and want them to handle the whole AR loop. Our API is for teams that want their own branded invoice document, multilingual templates, or more control over numbering and storage — without paying Stripe Invoicing per-invoice fees.
What languages and currencies are supported?
Built-in templates ship in English, Japanese, Simplified Chinese, Traditional Chinese, Korean, Spanish, and Russian. The tax/currency engine supports 150+ ISO currencies with locale-aware formatting.
Do invoices comply with EU/UK/JP e-invoicing rules?
We ship sensible defaults (VAT breakdown, sequential numbering, supplier/customer details) that satisfy most invoice requirements. For Peppol/EN16931 XML export, follow the docs — it is supported on the Pro plan.
Can I store invoices on my own infrastructure?
Yes. Set the response_format to bytes and we return the PDF inline so you can write it to your own S3/R2/Azure Blob. By default we also host the PDF and give you a signed URL.

Start sending invoices from your code

Read the docs, grab an API key, and you can have an invoice rendering in under five minutes.

Read the API docs Generate one in the UI