Payroll integration
Factorial to Nmbrs integration: HR changes from Factorial ready for the Dutch payroll run
With an integration between Factorial and Nmbrs, new employees, contract changes, salaries, bank accounts and terminations of the Dutch entity go from Factorial to the right Nmbrs company, with their effective date. Payroll processes them in the payroll run and only completes the Dutch tax details.
What the integration does
Employers that use Factorial for HR and have an accounting firm run Dutch payroll in Nmbrs email a list of changes every month. A changed bank account or pay rise therefore sometimes reaches the run a month late.
- HR records a change in Factorial. Factorial reports it to KoppelHet.
- KoppelHet fetches the HR changes of the Dutch legal entity, per kind, such as hire, contract, bank account and termination.
- A hire becomes a new employee in the right Nmbrs company, with employment, hours and salary.
- Contract and salary changes go to Nmbrs with their effective date; pay components follow a lookup table.
- Before the cut-off KoppelHet compares Factorial and Nmbrs and reports differences to payroll.
What to watch for with Factorial and Nmbrs
- Factorial has a separate stream of HR changes intended for external payroll, per kind, such as hire, contract, bank account, address and termination. KoppelHet reads that stream per kind and only for the Dutch legal entity, so Spanish changes never end up in Nmbrs.
- The kinds of changes in Factorial are partly set up for Spain, for example with a separate kind for Spanish income tax. Factorial does not hold Dutch tax data such as the payroll tax credit; the accounting firm completes it in Nmbrs, and the integration does not overwrite it.
- Contracts are stored in Factorial as versions with an effective date. Nmbrs works per payroll period; KoppelHet puts a new version in the period in which the effective date falls, and reports a retroactive change separately.
- Pay items in Factorial belong to concepts the organisation sets up itself. A lookup table links each concept to a pay component in Nmbrs; a new concept without an agreement becomes a notification instead of a silent pay line.
- Factorial retries a failed notification up to twenty times in 48 hours and then disables the subscription. KoppelHet has the warnings about this sent to its own operations and still checks before every cut-off that all changes have been processed.
- Factorial puts the API version in the address, with a date. KoppelHet first tests a new version in Factorial's demo environment before the integration switches, so a change on Factorial's side does not cause an error in the payroll run.
- If payroll runs through an accounting firm, the firm gives the integration its own employer-level login in Nmbrs. The firm's other clients stay out of view.
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
Are sickness reports passed on too?
Factorial also supplies sickness and leave changes. Whether they go to Nmbrs or to an absence system is agreed per customer.
Can we set this up while Factorial is still being implemented?
Yes. Factorial has a demo environment, so we test with your setup and go live once the Dutch entity in Factorial is ready.
What about the GDPR?
You are the controller and KoppelHet is the processor, under a data processing agreement. Every change the integration passes on is in the audit logging.
Technical details for IT
For those who want to know how it works under the hood: APIs, fields and sources used.
- Factorial is read through the Factorial API (version 2026-07-01 in the path) with OAuth 2.0 - employee updates (summaries, new hires, contract changes, personal changes, terminations, absences) filtered on legal_entities_ids and starts_on, contract versions, compensations with concepts and legal entities. Webhook subscriptions with up to twenty attempts in 48 hours, then disabled; technical contact for API notifications configurable in Factorial.
- Nmbrs is written through the Nmbrs REST API with OAuth 2.0 and an employer-level login. The SOAP API stops on 1 March 2027.
Which fields are transferred
The key fields. The full mapping is agreed per customer.
| Field in Factorial | Field in Nmbrs | Notes |
|---|---|---|
Factorial employee id | Personeelsnummer of vrij veld | Fixed key |
Naam en geboortedatum | Persoonsgegevens | |
Identificatienummer | BSN | With the eleven test |
Legal entity | Nmbrs-bedrijf | |
Contract version (begin, uren, soort) | Dienstverband en rooster | With effective date |
Compensation met concept | Salaris of looncomponent | Lookup table per concept |
Bankrekening (update bank) | IBAN | |
Adres (update address) | Adres | |
Termination | Datum uit dienst |
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