Instead of hard-coding payroll rules, PayrollEngine models business logic as composable Regulation layers — versioned JSON/YAML config + runtime C# (Roslyn). Layers inherit and override like CSS cascade: national law → industry → company.

v0.10.0-beta.1 shipped earlier this week alongside the new docs site (payrollengine.org).

The most interesting new example: MultiCountryPayroll — DE/FR/NL sharing a single base regulation, with a split employee whose contract crosses borders mid-period. The regulation handles it without a single country-specific code path.

Other additions: - Payrun Preview: in-memory calculation, no DB writes - Async payrun jobs: HTTP 202, bounded queue, webhook on completion - Parallel employee processing with per-employee state isolation

Stack: .NET 10, SQL Server, Docker, Roslyn

GitHub: https://github.com/Payroll-Engine/PayrollEngine Docs: https://payrollengine.org