Connect Invoisio to your own systems.
Create invoices and quotes from your website, web shop, Zapier, Make or your AI assistant. One key, plain JSON.
What can the API do?
Clients and products
List, search, create, update and delete. Keeps your client list in sync with your own system.
Invoices
Create with lines, VAT and discount, fetch the PDF, send by email and send a reminder. Filter by status.
Quotes
Create, fetch the PDF, send, and turn into an invoice with a single call.
PDF templates
List, create and edit, preview, and choose the default template for invoices and quotes.
How to use it
Connected in three steps.
- Log in and go to Profile → API (you need to be an administrator).
- Create an API key and keep it safe. You only see it once.
- Send your requests to https://app.invoisio.com/api/v1 with the header "Authorization: Bearer" and your key. You get JSON back; lists come 25 at a time (ask for more with per_page).
Example: list sent invoices, and create an invoice for a client.
Start free# List sent invoices
curl "https://app.invoisio.com/api/v1/invoices?status=verzonden" \
-H "Authorization: Bearer YOUR_KEY" \
-H "Accept: application/json"
# Create an invoice (draft)
curl -X POST https://app.invoisio.com/api/v1/invoices \
-H "Authorization: Bearer YOUR_KEY" \
-H "Content-Type: application/json" \
-d '{
"client_id": 12,
"status": "concept",
"invoice_date": "2026-10-22",
"items": [
{"description": "Laying paving", "quantity": 1,
"unit_price": 450, "tax_rate": 21}
]
}'Frequently asked questions
Which plan do I need?
A paid Business or Enterprise plan. The API does not work yet during the trial.
Does it work with Zapier or Make?
Yes, with their step for a custom web request (HTTP or Webhooks). There is no ready-made Invoisio app in Zapier yet, and Invoisio does not send notifications out by itself. So let your scenario check for new invoices on a schedule.
Can my AI assistant use it?
Yes. On the API page in the portal you download INVOISIO.md: instructions for your AI, for example in Visual Studio Code. It also tells your AI to ask for your approval before sending anything to a client.
What is not (yet) possible through the API?
Hours, trips, receipts and the calendar, and outgoing notifications (webhooks), for example when an invoice is paid. They are on the list.
Is it secure?
Each key belongs to one company and only sees that company's data. Everything goes over https, and you revoke a key with one click.
Connect your first system.
Choose Business, create a key and you can start right away.