Senior Backend Engineer, Menu Personalization

Work with HelloFresh in Warsaw and its HelloTech organisation, HelloFresh’s global technology backbone with more than 1000 people, building the digital products that power our end-to-end food experience. From meal kits and ready-to-eat meals to specialty offerings like pet food and premium meat & seafood, HelloTech creates the platforms that bring tailored food solutions to millions of customers every month. Our subscription-based, direct-to-consumer model relies on technology at every step, from customer-facing apps and personalization logic to pricing, forecasting, supply chain optimization, and initiatives that help reduce food waste. While our brands operate independently to serve distinct customer needs, they are united by shared platforms, data, and operational excellence built by HelloTech. HelloTech works in autonomous, cross-functional alliances, each owning a specific product or domain end to end. By working with our Warsaw office, you will help shape scalable, data-driven products used across our markets, working with a modern tech stack and international teams to continuously improve how people discover, order, and enjoy HelloFresh’s products, today and in the future. About the role: What's in the Box Do you have a drive for building high-performance, scalable systems and engineering low-latency, resilient services? You will contribute to a high-impact, cross-functional project focusing exclusively on menu personalization, acting as the bridge between sophisticated recommendation algorithms and the millions of customers who use HelloFresh daily. In this capacity, you will provide expert services to design, implement, and improve the robust microservices that serve personalized culinary options across our global markets. Collaborating in an autonomous, agile environment alongside Data Scientists and Machine Learning Engineers, you will facilitate the delivery of the backend architecture that powers our personalization engine. At HelloTech, flexibility and cross-functional collaboration are core to how we work. While this role is aligned to a specific Alliance, strong candidates may also be considered for opportunities across different teams or projects. What you’ll do: The Recipe Architect & Build: Deliver the core of our personalization engine by engineering high-availability Golang microservices that power real-time recommendations. You’ll build and optimize Python/FastAPI services that rank recipes using ML embeddings and sophisticated multi-objective optimization algorithms. ML Operationalization: Partner closely with Data Scientists to translate complex statistical solutions and ML models into production-ready services. System Evolution: Shape the future of our personalization platform by re-architecting legacy components into scalable, event-driven systems that can handle millions of requests globally. Operational Excellence: Manage the full lifecycle of your services—from experimentation and local development to deployment and monitoring in production. Experimentation Support: Design and implement the backend infrastructure required to execute A/B tests and measure the impact of new recommendation strategies. Tech Stack Mastery: Work with state-of-the-art technologies including Kafka, Redis, SQS, FastAPI, Kubernetes, Docker, and PostgreSQL . Technical Guidance: Provide knowledge sharing and technical guidance to other engineering contributors through code reviews and architectural alignment. What you’ll bring: The Ingredients Professional Experience: Long-term (5+ yrs) work experience in backend engineering, with a strong focus on building distributed systems and microservices. Golang Expertise: Deep proficiency in Golang and experience with its ecosystem in a production environment. Python Familiarity: Comfortable reading, understanding, and contributing to Python codebases. You don't need to be a Python expert, but should be willing and able to familiarize yourself with Python/FastAPI services, work with da