OOtoto API Docs
Ototo API · Integration guide

Build on the Ototo API

Calculate Belgian company-car taxation, pull a full tax matrix for a vehicle, manage car details, and get notified when calculation rules change — all from your own product.

Ototo's calculators cover the recurring taxation and cost questions Belgian fleet, leasing, and HR software needs to answer for a company car: registration tax (BIV/TMC), yearly road tax (verkeersbelasting), benefit in kind (VAA), fiscal deductibility, rejected expenses, and the CO₂ employer contribution. The API exposes those same calculators so you can embed them directly instead of re-implementing Belgian tax rules yourself.

Environments

Every integration talks to one of two environments. Each has its own subscription key and its own data — nothing is shared between them.

Acceptance / sandbox

For development and testing. May change as new features roll out.

https://ototo-acc.azure-api.net/v1/

Production

Stable. Breaking changes ship under a new version number, not as in-place changes.

https://api.ototo.be/v1/

See Authentication for how to attach your subscription key to requests, and how to request credentials for each environment.

Quickstart

Every request is authenticated with a subscription-key query parameter. Here's a minimal call to retrieve a car detail from the acceptance environment:

Request
curl "https://ototo-acc.azure-api.net/v1/CarDetails/{carDetailId}?subscription-key=YOUR_SUBSCRIPTION_KEY"

And a call to /Calculate, the core taxation calculator, using an inline vehicle instead of a stored one:

Request
curl -X POST "https://ototo-acc.azure-api.net/v1/Calculate?subscription-key=YOUR_SUBSCRIPTION_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "version": "1",
    "carDetail": {
      "catalogPrice": 45000.00,
      "fuel": "Electric",
      "euroStandard": "NA",
      "kilowatt": 150.00,
      "nedC2": 0
    },
    "userProfile": {
      "postalCode": 2000,
      "status": "SelfEmployed",
      "registrationOn": "CompanyRegistration",
      "regionRegistration": "Flanders",
      "viewOptions": 63,
      "language": "nl"
    },
    "options": {
      "registrationDate": "2026-01-01"
    }
  }'
Calculation access

Calling /Calculate or /GetTaxMatrix requires calculation access to be enabled on your subscription, in addition to a valid key. If you get an unexpected 401, confirm this with your Ototo contact.

Where to go next