Sellsy integration guide
Welcome to the Sellsy integration guide with Fincome. This document guides you step by step to connect your Sellsy billing data to Fincome.
Prerequisites
Before starting, make sure that:
You are the administrator of your Sellsy account
You have an active API access (or an OAuth connection if enabled)
You are connected to your Fincome account
You have access to the Clients, Products, Invoices, Credit Notes modules in Sellsy
Introduction to the integration
The Sellsy integration allows automatic synchronization of the following entities:
Clients (companies)
Products & Prices
Invoices
Credit notes
Fincome transforms this data to produce useful financial indicators, even in the absence of subscriptions:
Monthly net revenue
Discount analysis
Excl. VAT / Incl. VAT comparison
Tracking of multi-currency payments
Customer billing cohorts
Integration steps
1. Connect to Sellsy from Fincome
Log in to your Fincome account.
Go to the Data tab.
Click Connect a new billing system:
Select Sellsy from the list
Follow the OAuth instructions (or enter your API credentials if necessary)
Once access is validated, the initial synchronization starts automatically.
2. Data synchronized
Customers
ID, name, email
Products & Prices
Product: ID, name or reference
Price: ID, amount excl. VAT, currency
Invoices
ID, linked customer, issue date, status, number
Lines: quantity, amount excl. VAT, discounts, VAT, period, currency, description
Credit notes
Same structure as invoices but with negative amounts
Detailed operation of the integration
Structured mapping: each Sellsy entity is translated according to a field-by-field mapping
Smart product filtering: only non-archived and compatible-type items are imported
Invoice lines: each line is analyzed individually to detect discounts, VAT, quantity, description, etc.
Converted amounts: excl. VAT amounts and discounts are also provided in the base currency
Billing periods: Fincome identifies periods (period_start / period_end) when they are provided in Sellsy
Import of credit notes: credit notes are imported with their lines and associated with their original invoices
No subscription required: even without subscription management in Sellsy, Fincome can reconstruct customer recurrence
To know
Duration of the first synchronization: a few minutes to several hours depending on volume
Daily synchronization: every night automatically
Manual changes: never overwritten by a resynchronization
Sellsy API rate limit: managed automatically by Fincome
Negative amounts for credit notes: interpreted automatically
Integration overview
Item
Detail
Integration method
OAuth 2.0 or API token
Supported entities
Clients, Products, Prices, Invoices, Credit Notes
Synchronization frequency
Daily (night)
Scope of the initial import
All data available in Sellsy
Synchronization method
REST API + pagination
Deletion of Sellsy data
Not propagated (deletions in Sellsy are not replicated)
Data settings
Behavior / Setting
How it works in Fincome
Archived products
Automatic exclusion
Invoice lines
Full import with discounts, VAT, periods, descriptions
Excl. VAT and Incl. VAT calculations
Automatic (field amount_tax_exc, tax_amount)
Currency conversion
Applied based on the currency_code field + invoice date
Handling of credit notes
Amounts reversed, but structure identical to invoices
Manual data
Editable without being overwritten during a new sync
Technical mapping (Sellsy → Fincome)
Customers
Sellsy field
Fincome field
id
original_id
name
name
Products & Prices
Sellsy field
Fincome field
id (product)
original_id
name or reference
name
price_excl_tax
amount
currency_code
currency_code
id
product_id (price)
Invoices
Sellsy field
Fincome field
id
original_id
date
date
number
invoice_number
status
status
company_id
customer_id
Invoice lines
Sellsy field
Fincome field
id
original_id (line)
quantity
quantity
amount_tax_exc
amount_excluding_tax_after_discount
tax_amount
tax_amount
description
description
period_start
period_start
period_end
period_end
currency_code
currency_code
Credit notes
Same structure as invoices, with:
Negative amounts
Statuses specific to credit notes
References to the same types of lines
Need help?
Our support team is available via the in-app chat or by email: [email protected]
Next steps
Check your KPIs in the MRR, Churn, and Cohorts views
Add other billing sources (Stripe, Chargebee, etc.)
Enrich your customer data (segmentation, company size...)
Schedule a session with your Customer Success to go further
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