Overview
Rent increases are a delicate topic for landlords: the legal requirements are complex, mistakes can be expensive, and the process is often tedious. The SaaS platform solves exactly this problem by bundling the entire workflow – from calculation through document generation to dispatch – into a single application.
The core of the platform is a calculation algorithm that models the applicable legal requirements and ensures that every rent increase is fair and legally compliant. The logic was developed and validated iteratively in close collaboration with legal experts. The letters generated from it are automatically checked for completeness and correctness before being sent to tenants.
The result: a production SaaS platform that gives landlords confidence and drastically reduces the time required for rent increases.
My Role
As CTO and technical lead, I was responsible for the platform’s entire technical strategy from June 2023 to November 2024. Together with one developer and one designer, we formed a small, highly effective team. My tasks ranged from fundamental architecture decisions and code reviews to direct feature development. Particularly important was close coordination with management and external legal experts to correctly translate domain requirements into software.
Tasks
- Technical leadership and architecture decisions – Defining the system architecture based on Laravel, selecting infrastructure components, and establishing development processes
- Rent increase calculation algorithm – Development of the central calculation logic in close coordination with legal experts, including extensive test coverage
- Property and case management – Dashboard for landlords to manage their portfolio and control ongoing rent increase cases
- Flexible PDF generator – Template-based generation of rent increase letters with different document templates, adaptable to different legal scenarios
- Automated quality control – Validation of the generated documents for completeness and consistency before dispatch
- Billing system and newsletter integration – Integration of a billing system for subscriptions and connection to a newsletter service
- Performance optimization – Scaling the application for rapidly growing user numbers using caching (Redis), full-text search (Meilisearch), and infrastructure tuning on AWS
Technical Highlights
Legally compliant calculation algorithm: The biggest challenge was translating complex tenancy law requirements into deterministic software logic. The algorithm accounts for rent increase caps, local comparative rents, and numerous special cases. An extensive test suite with real-world scenarios continuously ensured the correctness of the calculations.
Template-based PDF generation: The system produces legally compliant rent increase letters based on flexible templates. Different document types and justification methods are covered by a modular template system, followed by an automated check for content completeness.
Performance and scaling: As the user base grew, targeted optimizations became necessary – from query optimization and Redis caching to using Meilisearch for fast full-text search and scaling the AWS infrastructure. This kept the application reliable and performant even as demands increased.