Senior.NET Engineer

About the Position

Ciklum is looking for a Senior.NET Engineer to join our team full-time in Bulgaria. We are a custom product engineering company that supports both multinational organizations and scaling startups to solve their most complex business challenges. With a global team of over 4,000 highly skilled developers, consultants, analysts, and product owners, we engineer technology that redefines industries and shapes the way people live.

As a Senior.NET Engineer, become a part of a cross-functional development team engineering experiences of tomorrow. Ciklum’s client is a global payments technology company providing payment processing, acquiring, and financial technology solutions to businesses worldwide.

Responsibilities

• Lead the migration and redesign of legacy application functionality into scalable, cloud-ready microservices, maintaining total feature parity with existing business rules
• Build high-performance RESTful Web APIs using C#,.NET Core, and the ASP.NET framework to support high-volume, transactional processing
• Design relational data models, author complex T-SQL queries, and optimize performance across SQL Server and Azure SQL using Entity Framework
• Manage source control, build automated deployment pipelines, and support cloud-ready solutions within Azure and Azure DevOps (ADO)
• Analyze system requirements, troubleshoot high-volume transaction bottlenecks, and communicate complex architectural decisions with technical and business stakeholders

Requirements

• Senior-level proficiency in C#,.NET Core (8+), ASP.NET, REST APIs, and microservices architecture
• Proven track record modernizing legacy .NET Framework applications and web services into scalable, cloud-ready services
• Hands-on experience building high-volume, high-reliability transactional systems (fintech or payment processing background preferred)
• Expert-level knowledge of SQL Server and Azure SQL, including database design, T-SQL development, and performance tuning
• Deep experience using Entity Framework for Object-Relational Mapping (ORM) and data access layers
• Hands-on experience with Microsoft Azure and Azure DevOps (ADO) for version control, task tracking, and CI/CD pipeline management
• Full mastery of Microsoft Visual Studio and standard.NET software engineering workflows
• Exceptional analytical skills with strong written and verbal communication abilities
• Upper-Intermediate level of English or higher

Nice to Have

• Deep understanding of payment gateway architecture, transaction lifecycles, and payment domain security
• Exposure to modern frontend stacks (React.js) or traditional server-rendered UIs (ASP.NET MVC / Razor) with JavaScript and jQuery

We Offer

• Regular salary reviews based on performance
• Corporate events: webinars, offline parties, and meetups
• Internal Mobility Program
• Tailored education path (including full access to Udemy, certifications, etc.)
• 25 paid days off: 20 business days of vacation per calendar year + 5 undocumented sick leave days
• Additional health insurance
• 100% company-covered Multisport card, with discounts available for family members

About the Company

At Ciklum, we are always exploring innovations, empowering each other to achieve more, and engineering solutions that matter. With us, you’ll work with cutting-edge technologies, contribute to impactful projects, and be part of a One Team culture that values collaboration and progress. Since expanding to Bulgaria in 2022, we’ve been building a fast-growing team that thrives on learning, collaboration, and innovation. Join us on this exciting journey and help shape the future of our delivery center.

Explore, empower, engineer with Ciklum!

Interested already? We would love to get to know you! Submit your application. We can’t wait to see you at Ciklum.