Legacy Modernization
Timesheet Modernization Platform
Full Stack Modernization DeveloperThis project is relevant for clients who need careful modernization of older business software, especially legacy ASP.NET systems that must preserve business workflows while moving to a maintainable modern stack.
Overview
This project was a full-stack modernization of a legacy timesheet and leave-management system.
The legacy application used ASP.NET Web Forms, SQL Server, IIS-hosted pages, scheduled console jobs, SMTP email behavior, and local file storage. The rebuilt platform used Next.js, NestJS, PostgreSQL, TypeScript, and Docker-based local services.
What The Business Needed
The business needed a modern replacement that preserved the existing workflows while improving maintainability, security, reporting, and migration readiness.
Important areas included:
- Employee timesheet entry
- Working-day monthly save behavior
- Annual permissions and vacation days
- Employee and company management
- Role-based access for employees, HR, and admins
- HR/Admin dashboards and reports
- XLSX exports
- Email reminders and broadcasts
- Legacy data migration
- Audit logs and error tracking
My Full Stack Work
I worked across backend, frontend, migration, and validation.
Key work included:
- Legacy behavior and SQL Server schema analysis
- NestJS API development
- Next.js frontend workflow implementation
- PostgreSQL schema design
- TypeORM migrations and entities
- JWT auth and role guards
- Working-days monthly API and frontend editor
- HR/Admin report APIs and XLSX export endpoints
- Migration dry-run, execute, reconciliation, and run-comparison tooling
- SMTP settings, broadcast campaigns, and reminder campaigns
- Activity logs and error logs
- Dockerized local runtime with PostgreSQL and pgAdmin
- Backend and frontend validation with Jest, Supertest, and Vitest
Why This Project Is Relevant
This project is relevant for clients who need careful modernization of older business software.
It is useful for clients who need:
It shows the ability to understand a legacy system, preserve important behavior, and rebuild it into a maintainable modern platform.
- Legacy ASP.NET modernization
- Full-stack TypeScript application delivery
- PostgreSQL schema design
- SQL Server to PostgreSQL migration
- Internal HR/admin systems
- Role-based dashboards
- Report and Excel export workflows
- Email operations
- Audit/error logging
- Migration validation and cutover support
Project Images
