Senior.NET Developer
Primary stack
Job description
About the Position
We are looking for a Senior.NET Developer to join a team working on a cloud-based B2B SaaS platform used by enterprise clients to manage operational workflows, approvals, reporting, and integrations with internal business systems.
The platform is built mainly as a modular monolith with several supporting background services. The team is gradually improving the architecture, separating selected business domains, optimising database performance, and strengthening observability across production environments.
This role is suitable for an engineer who enjoys backend development, clean API design, database optimisation, and practical architecture work in a real production system.
Responsibilities
- Develop and maintain backend services using C#, .NET 8, and ASP.NET Core Web API.
- Work on a modular backend architecture with clear separation between business domains.
- Build and improve REST APIs used by web applications and external enterprise integrations.
- Work with Entity Framework Core, SQL queries, migrations, and database performance tuning.
- Optimise slow API endpoints, background jobs, and data-heavy workflows.
- Implement authentication and authorisation flows using OAuth2, OpenID Connect, JWT, and Microsoft identity-related services.
- Support integrations with external REST APIs, CRM systems, and internal enterprise platforms.
- Work with Azure App Service, Azure SQL, Azure Service Bus, and Application Insights.
- Improve logging, diagnostics, and error tracking using structured logging, for example Serilog.
- Participate in technical design discussions and help reduce technical debt.
- Review code, support engineering standards, and mentor less experienced developers.
Requirements
- 5+ years of commercial experience in.NET development.
- Strong experience with C#, ASP.NET Core, and backend API development.
- Practical experience with .NET 6+ /.NET 8 preferred.
- Solid knowledge of Entity Framework Core and relational databases, especially MS SQL Server.
- Experience with API design, validation, error handling, versioning, and integration patterns.
- Good understanding of authentication, authorisation, roles, permissions, and secure API access.
- Experience with asynchronous processing, queues, or background workers.
- Ability to analyse production issues, read logs, investigate performance bottlenecks, and propose realistic fixes.
- Good understanding of SOLID, clean architecture principles, and maintainable code practices.
- Experience with unit and integration testing.
- Strong spoken English - Upper-Intermediate / Advanced level, B2+ or higher.
Nice to Have
- Experience with Azure Service Bus, Azure Functions, or distributed background processing.
- Experience with multi-tenant SaaS platforms.
- Knowledge of Redis or other caching approaches.
- Experience improving legacy or partially monolithic systems.
- Experience with CI/CD pipelines in Azure DevOps or GitHub Actions.
We Offer
- Remote-friendly cooperation format.
- Work on a real SaaS product with active users and production challenges.
- Opportunity to influence backend architecture and engineering practices.
- Direct collaboration with experienced engineers, QA, DevOps, and product stakeholders.
- Long-term cooperation opportunities.
- Practical technical environment focused on delivery, quality, and ownership.
Apply
If you are a Senior.NET Developer who enjoys working with production backend systems, Azure-based infrastructure, and complex business logic, we would be glad to hear from you.
Send us your CV and we will contact you to discuss relevant opportunities.
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Infinity Technologies, headquartered in London, specializes in creating global R&D hubs to help businesses achieve their goals. Promoting fully remote teams and a lean approach, we eliminate unnecessary office costs, sales, marketing expenses, and overheads for our customers. Our innovative fractal model ensures each R&D hub functions as a self-contained ecosystem tailored to the unique needs of each customer, acting as an extension of their team to develop products, maintain services, or execute strategic objectives.We leverage over 20 trademarked frameworks for building teams, developing software products, and designing outsourcing strategies, focusing on startups andmid-sizedcustomers. Our goal is to help them globalize their R&D efforts efficiently. Infinity Technologies also maintains a library of reusable components, enabling rapid prototyping, idea validation, and faster time to market—all while reducing costs. Since 2003, we have built 81 R&D hubs and currently operate 12 active hubs with distributed teams in 21 countries.With our expertise in cost-effective practices, economies of scale, and lean methodologies, Infinity Technologies empowers businesses to innovate, grow, and succeed in a global marketplace.
