Senior Backend Developer - Warsaw, Poland

John Galt LLC.; Warszawa; Ibrido; PLN 260.000 - 380.000; Tempo pieno

Descrizione del lavoro

John Galt LLC in Warsaw, Poland is seeking a Senior Backend Developer with 8+ years of professional software development experience. You will design, build, and maintain scalable backend systems and APIs using C#, .NET and .NET Core, with strong emphasis on performance and reliability.

You will collaborate with frontend teams, contribute to architecture, optimise SQL Server databases, and ensure code quality, security, and maintainability across enterprise applications.

Competenze

• 8+ years of professional software development experience, backend focus.
• Extensive experience with C#, Microsoft .NET, and .NET Core.
• Strong experience developing REST APIs, backend services, and business-critical applications.
• Solid knowledge of SQL Server, relational DB design, and query optimization.
• Understanding of software architecture, OOP, design patterns, and SOLID principles.
• Experience with automated testing, debugging, Git, and modern development practices.
• Ability to own complex technical projects and solve challenging problems.

Mansioni

• Design, develop, and maintain backend services and applications using C#, .NET, and .NET Core.
• Build and maintain RESTful APIs and integrations supporting React-based applications.
• Design and optimize database structures, queries, and stored procedures using SQL Server.
• Develop scalable, secure, and maintainable software following established architecture and design principles.
• Identify and resolve complex technical issues, improve system performance, and ensure application reliability.
• Participate in technical design discussions, code reviews, testing, and continuous improvement initiatives.
• Collaborate with cross-functional teams to translate business requirements into effective technical solutions.
• Provide technical guidance and support to other developers.

Conoscenze

C#

REST APIs

SQL Server

React

Git

SOLID principles

OOP

Testing

Strumenti

.NET Core

Azure

AWS

PostgreSQL

Docker

CI/CD pipelines

Node.js

React

SQL Server

Descrizione del lavoro

Senior Backend Developer - Warsaw, Poland

It's Time to Love Your Job Again!

We’re seeking a Senior Backend Developer with at least 8 years of professional software development experience and strong expertise in C# and Microsoft .NET. The ideal candidate will have a proven track record of designing, developing, and maintaining scalable backend systems, APIs, and enterprise applications, with experience integrating backend services with React-based applications.

The role involves developing robust server-side solutions, optimising database performance, and contributing to software architecture and technical decisions. Working closely with frontend developers, product teams, and other engineers, the successful candidate will help deliver reliable, high-performing applications while maintaining high standards of code quality, security, and maintainability.

Key Responsibilities

• Design, develop, and maintain backend services and applications using C#, .NET, and .NET Core.
• Build and maintain RESTful APIs, business logic, and integrations supporting React-basedapplications.
• Design and optimise database structures, queries, and stored procedures using SQL Server.
• Develop scalable, secure, and maintainable software following established architecture and design principles
• Identify and resolve complex technical issues, improve system performance, and ensure application reliability.
• Participate in technical design discussions, code reviews, testing, and continuous improvement initiatives.
• Collaborate with cross-functional teams to translate business requirements into effective technical solutions.
• Provide technical guidance and support to other developers.

Requirements

• At least 8 years of professional software development experience, with a strong focus on backend engineering.
• Extensive commercial experience with C#, Microsoft .NET, and .NET Core.
• Strong experience developing REST APIs, backend services, and business-critical applications.
• Solid knowledge of SQL Server, relational database design, and query optimisation.
• Understanding of software architecture, object-oriented programming, design patterns, and SOLID principles.
• Experience with automated testing, debugging, Git, and modern development practices.
• Strong problem-solving skills and the ability to take ownership of complex technical projects.

Required Technologies: C#, .NET / .NET Core, REST APIs, SQL Server, Git, and React.
Desirable Experience: Microsoft Azure or AWS, PostgreSQL, Node.js, Docker, CI/CD pipelines, microservices, and enterprise SaaS platforms.

Full Time
Remote, Warsaw, Poland