About Lumo
Lumo is Proton's privacy-first AI assistant that fundamentally reimagines how AI should work - empowering users without exploiting their data. Unlike traditional AI platforms that harvest user conversations for training and profit, Lumo operates with zero-access encryption, keeps no server-side logs, and ensures that conversations remain completely confidential.
Built by the team behind Proton Mail, Proton VPN, and backed by the nonprofit Proton Foundation, Lumo represents a paradigm shift in AI development. We believe the benefits of AI are too great to miss, but the privacy risks of current implementations are too serious to ignore. Lumo is based on open-source language models, operates from Proton's European datacenters, and provides unprecedented transparency in the AI space.
Our Mission: To deliver the full power of artificial intelligence while maintaining user privacy as an uncompromising core principle. We're building an AI that only works for you, not the other way around - where your conversations remain confidential and your data stays fully under your control, never shared, sold, or stolen.
Our Technology: Lumo implements multiple layers of encryption throughout the entire pipeline, from device-to-server communication through to long-term storage, creating a privacy architecture that's simply much stronger than anything else on the market. The platform runs on open-source models including Mistral's Nemo and Nvidia's OpenHands 32B, with full source code transparency.
Role Summary
We are seeking a passionate and skilled Frontend Engineer to join our growing Lumo AI team. You’ll work across all functions of Lumo, turning designs into responsive, fast and reliable interfaces. Your code will shape the day‑to‑day experience of users, making it smoother, clearer, and more enjoyable.
Full Stack Engineering
Create, evolve and sustain high‑performance features that tie together the front‑end and back‑end layers of our modern stack. Ensure every component scales smoothly and integrates cleanly.
What You Will Do
- Turn UI mockups into production‑ready React components.
- Integrate those components with our backend services using TypeScript and modern data‑fetching patterns.
- Optimize performance so pages load instantly even on slower connections.
- Collaborate closely with product managers, designers and other engineers to ship features end to end.
- Own the quality of your work: write tests, document decisions and participate in code reviews.
- Spot friction in the user journey and fix it before it becomes a complaint.
What we expect
- Strong expertise in React.
- Solid grasp of TypeScript and JavaScript fundamentals.
- Experience with state‑management and data‑fetching libraries.
- Ability to produce clean, maintainable code without cutting corners.
- Good communication skills and a willingness to give and receive honest feedback.
- A proactive attitude – you identify problems and solve them, not wait for direction.
Nice to have
- Exposure to AI or large language model products.
- Python scripting for tooling or data tasks.
- Knowledge of distributed systems and observability stacks.
- Hands‑on experience with design tools such as Figma.