Nmbrs

Nmbrs API is comprehensive for HR and payroll integration, supporting both SOAP and REST protocols.

API key authentication is straightforward, with good sandbox environments for testing. The API covers employee data, payroll processing, company management, and reporting extensively. However, it requires deep understanding of Dutch/Swedish payroll concepts and period-based data structures. Multiple API versions can be confusing, and the interface reflects internal complexity.

It's ideal for payroll service providers and HR integrations, but expect significant onboarding time due to domain complexity.