HR to ERP
Factorial to Unit4 integration: employees and cost centres from Factorial in Unit4 ERP, per legal entity
With an integration between Factorial and Unit4 ERP, every employee from Factorial becomes an employee in the Unit4 company of their legal entity, with cost centre, manager and the dates from Factorial. A cost centre change or a move to another entity in Factorial takes effect in Unit4 on the same date, and the end of the contract terminates the employee.
What the integration does
Organisations that use Factorial as their HR system and Unit4 ERP for projects, hours and finance maintain cost centres and employees in Unit4 by hand. A cost centre change mid-month then arrives too late, and an employee who moves to another entity stays in the old Unit4 company.
- Factorial reports a new, changed or departing employee; KoppelHet fetches the employee and cost centres.
- KoppelHet determines the Unit4 company from the legal entity and groups per company.
- Unit4 validates the data beforehand; then employees are created or updated.
- Cost centres go along as relation value with start and end date.
- On the contract end date the employee is terminated in Unit4.
What to watch for with Factorial and Unit4 ERP
- Factorial records per employee which cost centres they work in, with a percentage and a start and end date. Unit4 stores a cost centre as relation value with its own validity. KoppelHet takes the cost centre with the largest percentage and gives it the same dates in Unit4, so hours from the change date land on the new cost centre.
- A move to another entity creates a new contract in Factorial that only applies from the effective date; until then the employee belongs to the old entity. Unit4 only accepts employees for one company per call. KoppelHet creates the employee in the new Unit4 company on that date and closes the employment in the old one.
- On a termination Factorial has two dates: the end of the contract and the date on which access to Factorial stops. Unit4 needs the end date of the employment. KoppelHet uses the contract end date and ignores the access date, which often falls earlier or later.
- Factorial can reverse a termination and sends its own webhook for it. Terminating in Unit4 gives a final status. KoppelHet therefore already sets the end date on the employment, but only terminates the employee once that date has passed, so a reversed termination only removes an end date in Unit4.
- A cost centre in Factorial has a code, but it is not mandatory, and it can be deactivated with a date. Unit4 expects an existing value and reports an unknown one in the validation beforehand. KoppelHet translates cost centres without a code through a finance table and reports a deactivated cost centre that still has employees on it.
- The internal employee number in Factorial is free text filled in by the organisation itself. In Unit4 the personId is unique within a company and Unit4 returns an error on an existing number. KoppelHet checks beforehand for empty or duplicate numbers per entity, so a new employee does not get stuck on that error.
How we build and run it
- The integration runs on the KoppelHet platform, hosted in a data centre in the EU.
- Every sync and every error is visible in the functional log; on an error your administrator is notified.
- A change that cannot go through is not half-applied but queued for another attempt.
- KoppelHet is ISO 27001 certified. Data travels encrypted and stays on the platform no longer than needed.
- After go-live we manage the integration and adjust it when your process changes.
- The integration fits next to your existing integration layer. Only the fields in the design are transferred; the platform keeps no register of its own.
Implementation and price
This is not an app you switch on. We build the integration for your organisation on our platform, with building blocks we reuse on every project. So it is custom work that does not start from scratch.
A consultant prepares the intake and analyses both systems. We then record the mapping and exceptions field by field, test in the test or acceptance environment and go live at a moment you choose. Costs are a one-off amount for the setup and a monthly amount for platform, monitoring and support.
Frequently asked questions
Do hours from Factorial also go to Unit4?
Not in this integration. It keeps employees and cost centres current; hours can be added later as an extension.
Technical details for IT
For those who want to know how it works under the hood: APIs, fields and sources used.
- Factorial API (version 2026-10-01) with OAuth 2.0 - employees (legal_entity_id, company_identifier, manager_id, terminated_on, is_terminating), finance/cost_centers (code optional, status, deactivation_date), finance/cost_center_memberships (employee_id, cost_center_id, start_date, end_date, percentage), employee_updates/terminations (contract_end_date versus terminated_on), contracts/legal_entity_changes (new contract from effective date). Webhooks for Employee creates, updates, terminates and unterminates and for Finance CostCenter.
- Unit4 ERPx through the Employees API - POST /v1/employees/validate, POST /v1/employees/batch (at most 200, one companyId), 409 on an existing personId, PATCH with AddOrReplaceById on relatedValues (relationId, dateFrom, dateTo) and employments, DELETE /v1/employees/{personId} as Terminate.
Which fields are transferred
The key fields. The full mapping is agreed per customer.
| Field in Factorial | Field in Unit4 ERP | Notes |
|---|---|---|
company_identifier | personId | Unique per Unit4 company |
first_name, last_name, email | Naam en e-mailadres | |
legal_entity_id | companyId | Lookup table |
cost_center_memberships (hoogste percentage) | relatedValues kostenplaats (dateFrom, dateTo) | |
manager_id | relatedValues leidinggevende | |
Startdatum contract | employments.startDate | |
contract_end_date | employments.endDate en Terminate |
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