About the Role

We’re hiring a backend engineer to keep our .NET platform running well and to improve it over time. A large part of the platform runs on .NET Framework: Windows Services, on-premises SQL Server, and a lot of message-driven work. It has been in production for years, and it shows. There are memory leaks nobody has tracked down yet, endpoints that slow down under load, and bugs that only appear in production.
Fixing that is the job. You’ll also help move parts of the platform forward, so we want someone who knows modern .NET well and can tell the difference between code that’s old and code that’s actually broken.

What You’ll Do
• Track down memory leaks, thread contention, connection pool problems, and slow queries in long-running services
• Work production incidents using Datadog to find the root cause
• Debug across process boundaries: queues, caches, background workers, and the database
• Fix defects and add functionality to the existing codebase without breaking what already works
• Design and tune caching, including invalidation strategies




• Build and maintain message-based workflows in RabbitMQ and MSMQ
• Write and optimize SQL Server queries, stored procedures, and indexes
• Help plan and carry out an incremental migration off .NET Framework where it makes sense
• Document design and architecture decisions
• Write tests with real coverage on the code paths you touch
• Collaborate with other engineering teams, product, and external partners

Required Qualifications
• 10+ years of backend development
• Strong .NET Framework 4.x experience. This is the main codebase, not a side part of it
• Strong .NET Core / .NET 8+ experience and knowledge of current patterns
• Windows Services and background process development
• Message queues (RabbitMQ, MSMQ, or similar), including retries, poison messages, and idempotency
• Distributed and in-process caching, and the failure modes that come with them
• SQL Server: complex queries, stored procedures, indexing,

📌 Sr. / Lead .NET Developer (Colombia)
🏢 Unosquare
📍 Colombia