Senior Backend Developer (C#, ASP.NET, MySQL)

Quick Facts

• Senior Backend Developer role focused on C#, ASP.NET, and MySQL
• Architect and scale core business platform; modernize a monolith via service decomposition

Description

A Senior Backend Developer will architect, build, and scale a core fintech business platform backed by MySQL and implemented using an ASP.NET 8 monolithic architecture. The role focuses on delivering new business functionality while modernizing the platform by decomposing legacy modules into independently deployable ASP.NET Core services. You will translate requirements into reliable backend systems, strengthen engineering practices, and improve automated testing and database/API performance.

Responsibilities

• Architect, build, maintain, and deploy new business features across the platform
• Collaborate with product and engineering teams; communicate with business stakeholders to translate requirements into technical solutions
• Implement and maintain data access logic using Dapper and MySQL
• Optimize database queries to preserve or improve performance and meet SLAs
• Introduce and maintain automated unit and integration test coverage using NUnit as part of feature development and service extraction
• Analyze and refactor legacy modules into independently deployable, testable ASP.NET Core services
• Follow a decomposition roadmap while keeping the existing monolith reliable
• Define service contracts and communication patterns between newly extracted services and the remaining monolith

Requirements

• 6+ years of professional C# and ASP.NET development experience
• 5+ years of experience working with SQL databases
• Strong background building and maintaining large-scale, scalable backend applications
• Experience defining service contracts, functional expectations, and testing boundaries
• Proven ability to introduce and expand automated testing practices in codebases with limited existing test coverage while maintaining development velocity
• Proficiency in C# backend API development
• Proficiency with .NET Core 7+ (Dependency Injection, Configuration, Logging)
• Proficiency with ASP.NET Core, MVC, and WebAPI
• Proficiency with Dapper and Json.NET
• Proficiency with HTTP, REST, and JSON
• SQL proficiency, particularly MySQL or MSSQL

Benefits

• Contribute to new product functionality while modernizing a large-scale application
• Meaningful involvement in backend architecture, service decomposition, database performance, and engineering quality
• Help improve automated testing practices and establish maintainable development standards across the platform