Experience

Full-Stack Software Engineer

SaleBee CRM · Nexzen Solution Ltd.

Jul 2023 - PresentFull timeDhaka, Bangladesh

At Nexzen Solution I work on SaleBee CRM, a live multi-tenant CRM used by business clients. I built and maintained it on ASP.NET 4.8, SQL Server and jQuery, migrated it to .NET 10, PostgreSQL and Next.js one phase at a time while keeping the old stack running, and today I own its frontend, backend and database.

Scope

  • Built features and handled production support on the legacy ASP.NET MVC, SQL Server and jQuery stack.
  • Planned and executed the strangler-fig migration from ASP.NET 4.8 MVC to .NET 10, routing features to the new stack incrementally while maintaining the legacy system alongside it.
  • Moved the production database from SQL Server to PostgreSQL with a purpose-built data-transfer tool, with zero downtime.
  • Rebuilt the frontend as a decoupled Next.js / TypeScript app on REST APIs, and built the endpoints the Flutter mobile app uses.
  • Now own the live product end to end: frontend, backend, database, deployments, release pipelines, backups and server security.

Highlights

  • Replaced an in-memory caching layer (LazyCache) with database-side filtering, pagination and PostgreSQL materialized views, cutting critical page loads from about 5 s to 500 ms.
  • Built an MCP server so customers can manage leads and follow-ups from AI assistants.
  • Built a .NET background service on RabbitMQ and FCM for scheduled reminders and bulk email, SMS and push notifications.
  • Added cache-busting for static assets so new releases are never blocked by stale browser caches.

Outcomes

  • Completed the move to .NET 10, PostgreSQL and Next.js with zero downtime, and took over the whole product end to end.
  • Critical pages load in about 500 ms instead of 5 s, and memory no longer grows with each tenant’s data.
  • Customers can now work with their CRM data from AI assistants through MCP.

Tech stack

C#.NET 10ASP.NET MVCPostgreSQLSQL ServerNext.jsTypeScriptRabbitMQ

Case study

SaleBee CRM

Zero-downtime move to .NET 10 and PostgreSQL, with critical pages 10× faster, on a live CRM I own end to end.

Read the full case study