LandlordOS, a new property management system, aims to fill the gap between expensive enterprise software and unwieldy Google Sheets for small-to-medium landlords. Developed by a developer who identified the common pain points of landlords managing 5-50 rental units, LandlordOS offers a balanced solution that is both simple to use and robust enough for real business operations. The system is built with modern, production-ready tools, including Next.js 16 for server-side rendering, TypeScript for type safety, and PostgreSQL for reliable data storage, among others.

The system's core features include property and unit management, tenant management, payment tracking, and maintenance requests. Security measures such as CSRF protection, rate limiting, input sanitization, and secure middleware ensure that user data is protected. The developer implemented a double-submit cookie pattern for CSRF protection and rate-limited authentication endpoints to 5 attempts per 15 minutes. Input sanitization was also prioritized to prevent XSS and SQL injection attacks.

LandlordOS underwent rigorous testing, with 31 integration tests using Vitest and 8 E2E tests using Playwright, all achieving a 100% pass rate. The deployment process was initially challenging, as Cloudflare Pages and Netlify did not support Next.js App Router with Server Components. Vercel was ultimately chosen for its native support of Next.js. The developer also shared lessons learned, such as the limitations of Edge Runtime and the importance of type safety and comprehensive test coverage.

Looking ahead, future enhancements include document upload for leases, automated rent reminders, financial reporting, a mobile app, and multi-language support. The developer encourages feedback from property managers, developers, and those building similar SaaS products. LandlordOS is a promising addition to the proptech space, offering a much-needed middle ground for property management.