Principal LLM Engineer

Supercell is looking for a hands-on builder with deep expertise in developing production-grade LLM applications, someone who thrives in a collaborative and entrepreneurial environment, and who is excited to define the craft of LLM engineering inside Supercell. Internally, this role is known as LLM Engineer.\n\n## About the Role\n\nSupercell AI team drives the company-wide AI agenda and acts as the subject matter expert team for all AI-related topics. Supercell is known for its small teams that can deliver global hit games. We want to equip our employees with the right tools to keep them super efficient and effective in the AI era, and automate internal and player-facing repetitive tasks using agents and bots. We are now preparing for a future where humans and agent team members work seamlessly side by side.\n\nWe’re looking for a Principal-level LLM Engineer who not only builds production-grade agentic LLM applications but also takes ownership of the craft of LLM engineering inside Supercell. This is a role for someone who can both set the standard for how we design and deploy LLM-powered systems and act as an internal advocate and trusted advisor — helping our teams imagine what’s possible, sell in the value of new approaches, and build with confidence.\n\n## What You’ll Do\n\n* Act as the craft owner for LLM engineering at Supercell — setting direction, sharing best practices, and raising the bar for what “great” looks like in LLM-powered systems.\n* Drive adoption of a wide range of LLM and agentic applications (e.g. in-game bots, player support, social insights, internal productivity tools).\n* Champion AI development tools as a particularly high-leverage use case — helping our teams accelerate workflows, code smarter, and build better systems faster.\n* Partner closely with game and functional teams to evangelize LLM capabilities and turn vague opportunities into concrete solutions.\n* Serve as a bridge between technical and non-technical stakeholders, clearly communicating the strengths, limitations, and business value of different approaches.\n* Monitor emerging developments in the LLM and agents space; assess technologies for safety, reliability, and performance; and build our internal “stack” of recommended approaches.\n* Lead the design and implementation of robust evaluation, monitoring, and safety frameworks for production LLM-powered systems.\n* Rapidly prototype and deliver production-grade systems — but also coach, mentor, and enable other engineers to build confidently themselves.\n\n## What We’re Looking For\n\n* Deep expertise in building production-grade LLM and agentic applications — including real-world experience with evaluation, monitoring, and scaling.\n* Strong background in LLM applications, with hands-on experience in AI development tools (e.g. code generation, debugging agents, tool-assisted workflows) and a perspective on how they fit into the broader LLM ecosystem.\n* Expert-level knowledge of core LLM concepts: RAG, CoT, reasoning models, memory, fine-tuning, tool use, self-correction.\n* Strong software engineering skills with the ability to deliver robust, production-ready solutions quickly.\n* A craft mindset: ability to define standards, set direction, and raise the bar across a company.\n* Excellent communication and evangelism skills — able to sell ideas, influence stakeholders, and build excitement around AI capabilities.\n* Comfort working independently as well as in small, fast-moving teams.\n* Positive, pragmatic, and collaborative mindset.\n* Passion for gaming or experience in the industry a plus.\n* PhD in ML or equivalent depth of expertise preferred.\n\n## Relevant technologies and platforms\n\n* LLMs: GPT, Claude, Llama, Mistral, Gemma\n* Agent technologies: OpenAI Agents & GPTs, Anthropic Agents, MCP, LangGraph, Amazon Bedrock Agents\n* ML: PyTorch, TensorFlow, ONNX\n* Data: Python, Databricks, Spark\n* Cloud: AWS, GCP\n* Infra: Docker. Kubernetes, Redis\n* Vector databases: Pinecone, Chroma, pgvector\n\n## Benefits and Compensation\nLuring you in with glitter, glamour, and gems is not what we seek to do. We develop Supercell as an employer for you to do your best work and to call this the best experience in your professional life. \nWe want you to enjoy your time here fully, so we structure our compensation and benefits to serve this purpose. It starts with perceiving you as a human being, not a resource. Read More\n\n## About Supercell\nWe are a games company based in Helsinki, Finland, with offices in San Francisco, Seoul, Shanghai, and London. Since our launch in 2010, we've released seven games globally – Hay Day, Clash of Clans, Boom Beach, Clash Royale, Brawl Stars, Squad Busters, and mo.co. \nTo make seven games, we've killed dozens along the way. That's because we're obsessed with quality. Our mission is to create great games that as many people as possible play for years and that are remembered forever. To achieve this goal, we put together the best possible teams and give them the freedom and independence to succeed. Read More\n\n## You Might Love It Here...\nIf you love games, Supercell is the place for you. We're made up of proactive, independent teams that have the freedom to do what they think is best for their players, our games, and the company. \nWe know it takes more than trust and independence to make great games, so we also take good care of our people, providing them with the compensation, work environment and resources they need to succeed and have fun while at it. Read More\n\n## You Are Not Your Job Title\nWorking with us means you won’t need to focus on chasing titles or climbing ladders. We’ve decided that our internal job titles don’t include prefixes like senior, junior, principal, or director. Instead, we embrace our non-hierarchical culture, allowing us to concentrate on what truly matters: doing what’s best for our players. Recognition isn’t tied to your job title, nor does your title define the impact you can have. \nFor hiring purposes, we do use industry-standard job titles to help attract talent. When it comes to public-facing spaces like LinkedIn, we trust and encourage everyone to select a title that feels most appropriate for them. Read More\n\n## This position is in Helsinki, but you're not?\nLuckily, moving to Helsinki is easier than you might think. No matter where you would be moving from, our dedicated people will help you from beginning to end. We're here to ensure the process is as smooth as possible for you, your family and whoever and whatever you bring along. In addition to cats and dogs, we've even relocated a horse. Read More\n\n## Not sure if you should apply?\nDo it! You might feel like you don't tick all the listed requirements with stellar scores. That's fine! We're here to help you succeed. Also, we're happy to learn about any specific accommodations you might require to fully engage in our recruitment process.\n\nAnd here's a video about what we do. (Best enjoyed with salmiakki and rye bread)_