.NET Backend Developer — 6-Month Project (Hybrid)

DOU Polska; Warszawa; Hybrid; PLN 180,000 - 240,000; Full time

Job summary

DOU Polska is hiring a Backend Engineer to contribute to the core index layer for video indexing and auto-tagging of sports events. You will build the C#/.NET backend and process algorithm signals, collaborating with AI teams to enhance performance and reliability.

Join a hybrid, highly autonomous team in Warsaw, working with Azure cloud, event-driven messaging, and modern ML inference pipelines for real-time processing at scale.

Qualifications

• : 5+ years of commercial .NET experience with C# and .NET; strong Azure cloud experience; familiarity with AI-assisted tooling (e.g., Claude, Cursor).
• - Proven ability to mentor peers and lead design discussions.
• - Experience with event-driven messaging (Azure Service Bus, Kafka).
• - Comfortable working in hybrid environments and distributed teams.

Responsibilities

• Build and maintain the C#/.NET backend infrastructure for video indexing and auto-tagging.
• Collaborate in design discussions, review code, and mentor teammates.
• Participate in on-call rotation and respond to operations escalations.
• Engage with AI/algorithm teams to integrate signals and improve indexing accuracy.

Skills

C# / .NET

Azure

Kafka

Azure Service Bus

Kubernetes

SQL

AI Tools

Mentoring

Distributed teamwork

Tools

Azure Service Bus

Kafka

Kubernetes

SQL

Job description

The Role

As a Backend Engineer at our client, you will contribute directly to the core index layer, processing video indexing based on signals from the algorithm team. Your work will power the auto-tagging engine - the system that splits sports games into distinct events and accurately assigns start and end times to each action. You will balance deep feature development with critical problem-solving in a highly collaborative, AI-integrated environment.

About The Product

The product is an AI-powered sports media platform used by major sports organizations to transform live broadcasts into personalized digital content at scale. Every live stream is continuously ingested, analyzed, and enriched with AI-generated metadata, enabling automatic detection of key moments, intelligent video indexing, and near real-time content creation.

Behind the scenes, the platform processes massive volumes of live and archived video 24/7, powering personalized fan experiences across web, mobile, social, and broadcast channels. The backend infrastructure is built for extreme throughput, low-latency processing, and elastic scaling, combining distributed microservices with production-grade ML inference pipelines to deliver reliable performance under unpredictable traffic peaks.

Team Structure & Collaboration

You will join a focused backend squad consisting of four developers, one QA, and one PM, led by the engineering manager. This squad sits within a larger group of two backend teams and two algorithm teams. Because the index layer relies heavily on algorithm signals, you will work in close daily collaboration with the AI and algorithm teams.

What You’ll Be Doing

• Video Indexing & Auto-Tagging: Build and maintain the C#/.NET backend infrastructure that interprets algorithm signals to index videos and auto-tag live sports events
• Technical Leadership: Elevate the team by actively participating in design discussions, driving code review standards, and mentoring fellow developers
• On-Call Rotation: Participate in a shared on-call pool (approximately one week every five weeks). While critical nighttime or weekend outages are rare, you must remain reachable and have access to a laptop to respond to operations team escalations
• Proactivity: Execute tasks independently, demonstrate strong problem-solving skills, and maintain prompt, proactive communication via Slack with the Israel-based team

What We Expect

• Strong proficiency in C# and .NET, with 5+ years of commercial .NET experience
• Hands-on experience developing within Azure cloud environments
• Familiarity with and daily use of AI-assisted engineering tools (e.g., Claude, Cursor)
• Excellent interpersonal skills with a proven ability to mentor peers and lead design discussions
• High autonomy, independent task execution, and proactive communication habits for effective distributed collaboration
• Familiarity with event-driven messaging services such as Azure Service Bus or Kafka
• Working knowledge of SQL databases (general proficiency; specific engines do not matter)
• Basic familiarity with DevOps terminology and Kubernetes (operational expertise is not required)
• Willingness to work in a hybrid mode, 3 days from the office in Warsaw

Why This Role Is Worth Your Time

• Direct ownership of pure backend compute at scale - no full-stack dilution, focusing entirely on high-load microservices, indexing engines, and real-time processing
• High-autonomy environment with modern workflows where AI tools (Claude, Cursor) are embraced to eliminate boilerplate and keep focus on architecture