Overview

Released under the MIT License, Payroll Engine processes payroll data through a REST API with configurable regulation layers. It handles time-stamped data and recurring or one-off payruns, and can produce reports for payslips, legal filings, or data exchange. That makes it a flexible building block for a larger product, not a complete payroll offering that removes the need to assemble and operate a service around it.

The framework is open source, but country regulations are commercial. That distinction matters: the license does not mean the regulatory content needed for a deployment is free. The backend is designed to run locally or through Docker Compose, and the adopter must provide a database separately.

Key features

The REST API covers tenant and employee management, payrun jobs, result queries, report output, and backend event webhooks. This breadth gives integration engineers ways to connect payroll operations to their platform, while leaving the surrounding product experience and deployment to the adopting team.

Payroll data can be time-stamped, and the engine supports recurring and non-recurring payruns. Its reports serve payslips, legal filings, and data exchange, making it relevant to teams that need payroll outputs within an existing workflow rather than a standalone payroll portal.

A built-in test framework supports case validation, payrun assertions, and regression testing. For teams maintaining payroll rules over time, these tools provide a way to check changes and calculations; they do not replace the need for someone to configure and validate the rules.

The .NET Client SDK includes typed REST clients, test runners, local script development tools, and JSON schemas for regulation validation. A browser-based application can manage tenants, employees, regulations, case data, payruns, reports, tasks, and developer logs. These tools give technical and payroll specialists a substantial working surface, but the product remains oriented toward teams able to integrate and operate it.

Pricing

Payroll Engine is free and open source under the MIT License. There are no paid plans or published seat or usage quotas in the stated pricing model. The important cost caveat is that country regulations are commercial, so teams should account for those separately when assessing a production deployment.

Platforms

Payroll Engine supports API, Linux, macOS, self-hosted, web, and Windows. Its backend is intended to run locally or through Docker Compose, with a separately provided database. The maker says the backend is a service and should not be used on the public Internet; authentication is disabled by default. API key and OAuth authentication are supported, so teams need to address access controls before deploying it.

Audit trails can be configured by category, but are disabled by default. That means adopters responsible for compliance or operational review need to configure auditing rather than assume it is active out of the box.

Who it's for

Payroll Engine is aimed at HR-tech and EOR platforms, payroll consultants and HR specialists, and DevOps or integration engineers. It is most appropriate when a team wants to embed payroll processing and has the technical capacity to configure regulations, provide infrastructure, and manage security. Companies wanting a managed payroll service rather than a framework should look elsewhere.

Questions and feature requests go to GitHub Discussions, while bug reports go to GitHub Issues; the project asks users to allow a few business days for responses.

Pros and cons

Pro: The MIT-licensed framework and broad REST API offer a flexible foundation for embedding payroll workflows in another platform.
Pro: Case validation, payrun assertions, regression testing, and .NET development tools support teams maintaining custom payroll rules.
Con: Country regulations are commercial, so the free framework alone does not cover the full cost of regulatory content.
Con: The adopter must supply a database and operate the backend; authentication and audit trails are disabled by default, and the backend should not be exposed to the public Internet.

Alternatives

PHPPayroll is worth considering for teams that want a self-hosted, open-source payroll option with a free edition and free trial. Its Open-Source Edition is 0.00 USD per free, with no license fees or monthly charges and full source-code access.

BIPO HRMS Payroll is an alternative for organizations seeking a paid payroll product with Android, API, iOS, and web platforms; its maker offers a free demo. Ramco Enterprise Asset Management is another paid option, with pricing that varies by installation type and industry requirements.

Rippling may suit teams considering a paid platform whose products can be purchased separately, though its Core Rippling Platform is required and most products are billed per employee per month, with some carrying a monthly base. RUN Powered by ADP offers paid payroll plans including payroll processing, tax filing, direct deposit, employee access, and multi-jurisdiction payroll in Essential Payroll; Select is a payroll and HR suite.

iiPay Global Payroll Platform is a paid, fully managed end-to-end payroll option across 170+ countries. Neeyamo Payroll offers paid fully managed payroll with a helpdesk and reports and dashboards. Mercans G2N is another paid API and web option.

For a broader comparison, browse Global Payroll Software.

Verdict

Choose Payroll Engine if you are building payroll into a larger platform and can take responsibility for integration, infrastructure, regulation sourcing, and secure configuration. Its open framework and developer tooling are compelling for that job. Look elsewhere if you need a turnkey or managed payroll service, or if you cannot keep the backend off the public Internet and configure authentication and auditing yourself.

	Payroll Engine	Payslip
Free plan	No	No
Free trial	No	Yes
Paid from	—	—
Open source	No	No
Platforms	api, Linux, macOS, self-hosted, Web, Windows	api, Web
Worker types	employees	both
Free plan	—	No

Payroll Engine vs Payslip

Payroll Engine

Payslip