Senior .NET Developer

Location: Serbia (remote-first; optional Belgrade meetups)
Engagement: Full-time or long-term contractor 
Start: November/December 2025

What you’ll do:

• Design, build, and own secure REST APIs and services used by global web and mobile clients.
• Ship features end-to-end across C#/.NET (Core) back end and Kendo UI/Telerik front end components.
• Optimize data access on SQL Server (indexes, profiling, stored procs) and improve performance at scale.
• Integrate AI language models (prompting, tone control) into user-facing workflows.
• Deploy and operate services on AWS (EC2, ALB/ELB, RDS, S3, CloudFront, CloudWatch, IAM).
• Collaborate with Product/Design; write clear tickets/specs; participate in code reviews and CI/CD.

Must have:

• 5+ years professional software development (web + console).
• Deep expertise with .NET/C#, ASP.NET MVC, .NET Core, LINQ, ADO.NET, AJAX, REST APIs, Web Services, WCF, WPF.
• Proven track record designing & maintaining secure RESTful services for global clients.
• Entity Framework Core and ADO.NET; strong SQL Server (complex queries, joins, indexing, stored procedures, triggers, functions).
• Solid responsive web skills (HTML5, CSS3, Flexbox/Grid, JavaScript/TypeScript; cross-browser/device).
• Hands-on with Telerik/Kendo UI (Grid, Charts, Scheduler, Dropdowns, TreeView) including customization, performance tuning, sorting/paging/filtering/export.
• Familiarity with Kendo UI for jQuery/Angular/React in enterprise apps.
• Practical experience integrating AI LLMs (API usage, prompt design, tone control).
• Comfortable with datasets/data tables/JSON/XML in modern web apps.
• AWS deployment & scaling (EC2, ELB/ALB, RDS, S3, CloudFront, CloudWatch, IAM). Azure is a plus.
• DevOps: CI/CD (Azure DevOps/GitHub Actions), IaC (Terraform/CloudFormation).
• Git proficiency (GitHub/GitLab/Azure DevOps).
• Excellent analytical/problem-solving and communication skills; stakeholder collaboration.
• BS in CS/IT or equivalent experience.

Nice to have (adds real value):

• Strong async/await, TPL, parallelism; SOLID/Clean Architecture, DDD-lite.
• Security: OWASP Top 10, authN/Z (JWT/OAuth2), input validation, secrets mgmt.
• Testing: xUnit/NUnit, integration tests, test doubles; Postman/REST Assured.
• Observability: structured logging (Serilog), metrics/tracing (OpenTelemetry), log stacks (ELK/EFK).
• Caching & messaging: Redis, RabbitMQ/Kafka.
• Containers: Docker; Kubernetes/ECS experience is a plus.
• Search/indexing (Elasticsearch/OpenSearch/Azure Cognitive Search).
• Image/video processing at scale; CDN tuning (CloudFront) and edge caching.
• Experience modernizing legacy WCF/WPF to .NET Core services.

How we work (Serbia):

• Remote-first with 3–4h overlap with EU/US stakeholders.
• Clear tickets, lightweight docs, and weekly demo/retro/meetings.
• Growth budget for certifications and courses.

Interview process:

• 30-min intro (Rubiks) — background & expectations.
• 90-min technical + final chat with CTO.