Newxel

We are seeking a highly skilled Backend Developer (C#) to join the fastest-growing sports-tech company in Poland, Warsaw. In this position, you will design, develop, and optimize backend systems to support our video streaming and asset management platform, ensuring seamless and high-quality content delivery to our users.

Requirements

• Bachelor’s degree in Computer Science, Software Engineering, or a related technical field
• 2+ years of hands-on experience in backend development using a high-level programming language (C#/Java)
• Experience developing and maintaining scalable APIs and backend services
• Strong interpersonal and communication skills, enabling effective collaboration with cross-functional teams and the ability to clearly convey technical concepts

Will be a plus

• Experience with cloud platforms and products (AWS/GCP/Azure)
• Familiarity with .NET Core
• Familiarity with React for frontend development

Responsibilities

• Collaborate with cross-functional teams to understand requirements and translate them into scalable and efficient backend solutions
• Design, develop, and maintain backend services and APIs for high-performance video streaming and AI Indexing systems, ensuring reliability, scalability, and performance
• Implement best practices for code quality, testing, and documentation to ensure the maintainability and extensibility of backend systems
• Optimize backend infrastructure and algorithms to enhance performance and minimize latency
• Troubleshoot and debug issues in production environments, providing timely resolutions to ensure uninterrupted service
• Stay updated on emerging technologies and industry trends, cloud computing, and backend development, and apply them to improve our platform
• Participate in code reviews, architectural discussions, and sprint planning sessions to drive continuous improvement and innovation

What we offer

• Competitive salary range
• Medical insurance
• Paid vacation and sick leaves
• MultiSport card
• Top equipment kit, co-workings
• Hybrid set of works (Office location: Warsaw)
• Collaborative and innovative work environment
• Career growth and development opportunities
• A chance to work with giants of the sports industry

About the project

Our partner leads the industry in generating dynamic sports videos for every digital destination. Their cutting-edge AI and Machine Learning technologies analyse live sports broadcasts from over 250 leagues and broadcast partners, including iconic names like the NBA, NHL, ESPN, FIBA and Bundesliga, to create personalized, short-form videos in real-time. The solution empowers media rights owners to unlock new revenue streams and deliver a tailored fan experience across every digital platform. Join the high-profile Engineering team and discover the forefront of sports contents innovation.

We are looking for a Machine Learning Engineer (MLE) to design, build, and productionize ML evaluation and automation pipelines that support large-scale model development workflows.

The role involves working closely with algorithm developers, ML researchers, and product teams to build robust and scalable systems that automate model evaluations, manage distributed data processing, integrate human-in-the-loop validation processes, and produce actionable evaluation metrics. This position offers full ownership over the system’s architecture, implementation, scalability, and operational robustness, enabling efficient and rapid ML experimentation at scale.

Requirements

Must Have

• B.Sc. in Computer Science, Software Engineering, or a related technical field
• 3+ years of production-level Python development
• 3+ years building ML pipelines, data processing systems, or model evaluation infrastructure
• Strong system design skills and hands-on experience building distributed, scalable systems
• Experience with cloud compute platforms (Preferably Azure) — compute, storage, and networking
• Proficiency with:
  • Containerized workloads (Docker, Kubernetes)
  • SQL / NoSQL databases
  • Experience integrating data annotation platforms or human labeling workflows
  • Strong ownership mindset, able to independently design, build, and operate complex ML infra systems

Strong Advantage

• Experience with Computer Vision workloads and ML inference pipelines
• Experience building ML serving infrastructure and model deployment systems
• Familiarity with ML experiment tracking tools (Weights & Biases, ClearML, MLflow, etc.)
• Experience with video processing pipelines and encoding technologies
• Familiarity with cloud-native monitoring and observability stacks

Bonus

• Prior experience building evaluation or benchmarking pipelines for ML models
• Experience designing quality evaluation workflows for ML-based products
• Experience working in ML-heavy product companies or applied AI domains

Responsibilities

• Design and implement end-to-end ML evaluation pipelines supporting large-scale model assessments
• Build distributed data processing pipelines for ML inference, pre-processing, post-processing, and data transformation tasks
• Integrate human-in-the-loop annotation and validation systems as part of the evaluation workflow
• Design and implement scalable job orchestration, task dispatchers, and worker-based architectures for parallel ML workloads
• Manage storage, indexing, and retrieval of intermediate and final data artifacts
• Develop monitoring, logging, alerting, and observability for the entire pipeline
• Collaborate with algorithm and research teams to define flexible and reusable infrastructure components
• Automate manual and ad-hoc processes into robust, production-grade workflows
• Optimize resource utilization and ensure cost-effective pipeline operations.

Why this role

• Full ownership of designing critical ML infrastructure from the ground up
• Direct impact on ML development velocity and model quality
• Work with experienced ML researchers and engineers on production-grade systems
• Exposure to real-world applied AI workflows, cloud-scale systems, and automation challenges

What we offer

• Competitive salary range
• Medical insurance
• Paid vacation and sick leaves
• MultiSport card
• Top equipment kit, co-workings
• Hybrid set of works (Office location: Warsaw)
• Collaborative and innovative work environment
• Career growth and development opportunities
• A chance to work with giants of the sports industry

About the project

Our partner leads the industry in generating dynamic sports videos for every digital destination. Their cutting-edge AI and Machine Learning technologies analyse live sports broadcasts from over 250 leagues and broadcast partners, including iconic names like the NBA, NHL, ESPN, FIBA and Bundesliga, to create personalized, short-form videos in real-time.

The solution empowers media rights owners to unlock new revenue streams and deliver a tailored fan experience across every digital platform. Join the high-profile Engineering team and discover the forefront of sports contents innovation.

🚀 Hello, guys! We’re looking for a Senior Full-Stack Developer (React.js + .NET) to join an innovative R&D team in Warsaw for full-time employment.
You’ll be part of a fast-growing Sport-tech product company that’s using AI to help leading global sports brands create and deliver real-time video content. 

If you’re interested in building high-performance tools that reach millions of users, this could be a great opportunity for you.

📍Type of work: hybrid format (2-3 days/week in the office - Warsaw, Poland)

⭐English: Upper-Intermediate.

🕐Engagement: Full-time, long-term cooperation. 

📌Responsibilities:

• Build and maintain a high-performance, browser-based video editing platform used by global media teams;
• Develop client-side features using React.js + TypeScript and server-side logic using C# / .NET Core;
• Design and implement modular, reusable components for timeline management, video preview, trimming tools, overlay controls, and more;
• Develop and maintain scalable backend APIs for video rendering, encoding, and delivery;
• Collaborate closely with Product, Design, QA, and Engineering teams in daily standups, planning sessions, and code reviews;
• Ensure robust testing, clean documentation, and smooth CI/CD pipelines to support reliable deployments;
• Monitor system behavior in production, identify issues across the stack, and deliver timely fixes;

• Share knowledge with peers, contribute to internal engineering initiatives, and stay up to date with industry trends in video tech. 

   

📍Requirements:

• 4+ years of hands-on experience building production-grade web applications (Full-stack);
• Strong knowledge of React.js, TypeScript, JavaScript, modern HTML/CSS;
• Solid experience with C#, .NET Core, asynchronous programming, and RESTful API design;
• Familiarity with SQL and basic knowledge of NoSQL tools like Redis;
• Practical understanding of cloud infrastructure (preferably Azure, AWS, GCP) and CI/CD tools like GitHub Actions or Azure DevOps;
• Ability to debug complex systems and write maintainable, testable code;
• English: Upper-Intermediate;
• Strong communication skills and comfort working with cross-functional teams;

• Self-motivated with a focus on delivering great user experiences.

   

Will be a plus:

• Experience working with multimedia/video frameworks or streaming protocols (HLS, MPEG-DASH);

• Familiarity with event-driven architectures and messaging systems (e.g., Kafka, Service Bus);

   

🎁What we offer:

• A Decent salary range;
• Medical insurance;
• Paid vacation and sick leaves;
• MultiSport card;
• Top equipment kit, co-workings;
• Hybrid set of works (Office location: Warsaw);
• Collaborative and innovative work environment;
• Career growth and development opportunities;
• A chance to work with giants of the sports industry.

🚀 Hello, guys! We’re looking for a Middle/Middle+ Front-End Developer (React.js) to join an innovative R&D team in Warsaw.
Our client develops advanced, AI-powered technology that automatically transforms sports broadcasts into personalized, engaging content for fans around the world. 

In this role, you’ll leverage React.js, TypeScript, and state-of-the-art video editing technologies to deliver seamless, high-quality user experiences. 

You’ll collaborate with cross-functional teams, taking an active role in shaping and evolving the frontend architecture that powers next-generation sports content solutions.

📍Type of work: hybrid format (2-3 days/week in the office - Warsaw, Poland)

⭐English: Upper-Intermediate;

🕐Engagement: Full-time, long-term cooperation. 

📌Responsibilities:

• Develop and deliver high-quality, scalable UI features using React.js, TypeScript, and other modern web technologies;
• Design and maintain a modular JavaScript SDK that integrates media players and interactive UI components into diverse web environments;
• Collaborate closely with Product Managers, UX Designers, QA Engineers, and fellow developers throughout the development lifecycle;

• Participate in our Frontend Guild – a collaborative space for mentoring, sharing best practices, and exploring the latest frontend innovations.

   

📍Requirements:

• 3+ years of experience in frontend development within high-tech product companies;
• 3+ years working in cloud-based environments and with CI/CD pipelines;
• Strong expertise in JavaScript (ES6+), React.js, and TypeScript, with a solid track record of building scalable, production-grade applications
• Proven experience in SaaS product development and working with cloud-based environments;
• Solid understanding of responsive design principles and cross-browser compatibility;
• Good command of HTML5 and CSS3, with familiarity in modern web standards and best practices;
• Strong problem-solving mindset, analytical thinking, and a passion for clean, maintainable code;

• Bachelor’s degree in Computer Science or a related field.

   

✅Will be a plus:

• Experience with Microsoft Azure;

• Back-End or full-stack development experience.

   

🎁What we offer:

• A decent salary range;
• Medical insurance;
• Paid vacation and sick leaves;
• MultiSport card;
• Top equipment kit, co-workings;
• Hybrid set of works (Office location: Warsaw);
• Collaborative and innovative work environment;
• Career growth and development opportunities;
• A chance to work with giants of the sports industry.

About the project

Our partner leads the industry in generating dynamic sports videos for every digital destination. Their cutting-edge AI and Machine Learning technologies analyse live sports broadcasts from over 250 leagues and broadcast partners, including iconic names like the NBA, NHL, ESPN, FIBA and Bundesliga, to create personalized, short-form videos in real-time.

The solution empowers media rights owners to unlock new revenue streams and deliver a tailored fan experience across every digital platform. Join the high-profile Engineering team and discover the forefront of sports contents innovation.
We’re seeking a skilled and driven Python Developer to join a trailblazing team at the forefront of AI-powered sports content technology. In this role, you’ll design and build cutting-edge Python services, APIs, and automations that power next-generation sports content experiences. You’ll collaborate with cross-functional teams to deliver high-performance, scalable solutions used by leading sports brands around the world. This is your opportunity to combine top-tier engineering with a passion for sports, helping to shape products that fuel fandom for millions of fans worldwide.

Requirements

• Bachelor’s degree in Computer Science or an equivalent background
• 2+ years of professional experience as a Python Developer/Software Engineer
• Strong proficiency in Python (must); experience with a framework such as FastAPI, Django, or Flask
• Solid software engineering fundamentals: OOP, design patterns, LLM, testing, debugging
• Experience with REST APIs and asynchronous programming
• Proficiency with Git and CI/CD; Docker experience or/and Kubernetes – advantage
• SQL skills and experience with analytical database (Snowflake or similar) – advantage
• Experience with Airflow – advantage

• Excellent communication and collaboration skills

   

Responsibilities

• Design and develop scalable, efficient Python services, APIs, and automations
• Build data pipelines and integrations that power products and internal tools
• Own features end-to-end: design, implementation, CI/CD, monitoring, and observability
• Optimize performance, reliability, and security across services
• Collaborate with Product, R&D, Operations, and Business teams to deliver impactful solutions
• Work with cloud environments and containerized deployments

• Build and schedule workflows with Airflow and integrate with data platforms

   

What we offer

• Competitive salary range
• Medical insurance
• Paid vacation and sick leaves
• MultiSport card
• Top equipment kit, co-workings
• Hybrid set of works (Office location: Warsaw)
• Collaborative and innovative work environment
• Career growth and development opportunities

• A chance to work with giants of the sports industry

   

About the project

Our client is building a next-gen cloud platform that helps digital services deliver content faster, safer, and more reliably worldwide. It combines intelligent traffic routing, multi-CDN management, and built-in security to ensure 99.999% uptime and optimal performance — even during outages or network degradation. The system automatically selects the best delivery path based on geolocation, traffic type, and time of day, reducing latency and cutting delivery costs. The product is built for scale and trusted by streaming, gaming, e-commerce, SaaS, and fintech businesses.

We’re looking for a Software Engineer (Python/Go) to become the core of a new R&D hub in Warsaw. The ideal candidate has experience with Go or a strong desire to grow in that direction. You’ll contribute to the development of a modern cloud platform used by global online services. It’s a great opportunity to influence core architecture while growing in a technically strong and product-focused environment.

Responsibilities

• Design and develop complex backend systems for high-volume, data-intensive applications
• Take ownership of projects, including building systems from scratch, designing architecture, and ensuring end-to-end delivery
• Collaborate with cross-functional teams, including Back End Team, CEO and DevOps, to deliver innovative solutions
• Solve challenging problems with a strong analytical mindset and propose creative solutions
• Optimize and maintain existing systems to ensure performance, scalability, and reliability
• Continuously learn and adopt new tools, technologies, and best practices

Requirements

• 7+ years of experience in backend software development, with a strong focus on Python or Go
• Practical experience with Go will be a plus
• Expertise with cloud platforms such as AWS/GCP
• Strong familiarity with microservices architecture
• Strong understanding of algorithms and data structures
• Fundamental understanding of object-oriented programming and multithreading
• Expertise with database systems and optimizing database performance
• Excellent problem-solving skills and a proactive approach to owning and delivering projects
• A strong analytical mindset with the ability to tackle complex technical challenges
• Excellent interpersonal skills, with the ability to collaborate effectively in a team environment
• A self-driven and independent mindset, eager to take full ownership of projects and continuously innovate
• Proficiency in English at Upper-Intermediate level (B2+) or higher

What we offer

• Competitive salary and benefits package
• Medical insurance
• Full Remote
• Collaborative and innovative work environment
• Career growth and development opportunities
• A chance to work with a talented and driven team of professional

We’re looking for a skilled Data Scientist with a focus on AI data to power the next generation of intelligent solutions. This role is perfect for someone who thrives on tackling complex challenges through machine learning, advanced analytics, and coding, and who’s eager to drive innovation through cutting-edge AI methodologies.

Responsibilities

• Semantic Modeling: Design and maintain semantic representations (e.g., ontologies, entity relationships) to enhance structured data queryability and AI-driven reasoning
• Natural Language to Structured Query Mapping: Design and evaluate approaches that interpret natural language questions and accurately map them to structured data queries (e.g., SQL or semantic equivalents)
• Data-to-Text Interpretation: Design and evaluate techniques for interpreting tabular data and generating human-readable natural language explanations
• LLM Prompt Strategy: Assist in developing and refining prompt engineering strategies to ensure accurate, interpretable, and relevant responses from large language models
• Model Evaluation and Enhancement: Continuously evaluate, refine, and improve existing AI models and algorithms to enhance accuracy, scalability, and computational efficiency
• Research & Innovation: Stay current on advancements in AI, GenAI, NLP, and machine learning, incorporating promising techniques and ideas into product solutions
  
  Requirements
• Master’s degree in Computer Science, Data Science or Applied Mathematics is required; a Ph.D. is strongly preferred
• 5+ years of experience in Data Science field
• Proficiency in Python and common AI/ML libraries (e.g., PyTorch, TensorFlow, scikit-learn, Hugging Face Transformers, Langchain, Langgraph)
• Strong MLOps experience to help build, deploy, and maintain machine learning models in production. Familiarity with cloud platforms (e.g., AWS, GCP, Azure)
• Experience with Agentic system design
• Focus on researcher experience in writing articles
  
  What we offer
• Competitive salary and benefits package
• Medical insurance
• Full Remote
• Collaborative and innovative work environment
• Career growth and development opportunities

• A chance to work with a talented and driven team of professionals
  
  About the project

  Our client develops a unique in-memory platform using innovative Machine Learning technologies. The product aims to help businesses’ achieve data and analytics processing needs with the highest speed, and to deliver real-time performance by reproducing companies’ data to the in-memory data store. An impressively fast-growing company that partners with the most leading enterprises from all over the world within various industries including healthcare, telecommunications, retail, etc.