Prerequisites

Before starting, make sure that:

• You are an administrator of your Sellsy account
• You have active API access (or an OAuth connection if enabled)
• You are logged in to your Fincome account
• You have access to the Customers, Products, Invoices, Credit notes modules in Sellsy

Overview of the integration

The Sellsy integration automatically synchronizes the following entities:

• Customers (companies)
• Products & Prices
• Invoices
• Credit notes

Fincome transforms this data to produce useful financial indicators, even in the absence of subscriptions:

• Net monthly revenue
• Discount analysis
• Net / gross comparison
• Multi-currency payment tracking
• Customer billing cohorts

Integration steps

Connecting to Sellsy from Fincome

1. Log in to your Fincome workspace
2. Go to the Data tab in the Settings
3. Click Connect a new billing system
4. Select Sellsy from the list
5. Follow the OAuth instructions (or enter your API credentials if necessary)

Once access is validated, the initial synchronization starts automatically.

Verify the integration

1. Go to the Sources tab in Fincome
2. Check the status of the last synchronization
3. Check the Customers, Revenue, Documents views
4. The data should be present, with your invoices and credit notes

Updated on: 03/07/2026