Frontend Engineer; Lumo AI

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.

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.

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 Open Hands 32B, with full source code transparency.

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.

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.

• Turn UI mockups into production‑ready React components.
• Integrate those components with our backend services using Type Script 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.

• Strong expertise in React.
• Solid grasp of Type Script 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.

• 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.

You'll be joining a mission‑driven team at Proton, trusted by over 100 million people worldwide and owned by the nonprofit Proton Foundation. This role offers the opportunity to shape the future of AI by building fullstack infrastructure that proves privacy, performance, and reliability aren't mutually exclusive.

• Work that Matters: millions of people trust Proton with their privacy. We answer only to our users — not advertisers, not investors with conflicting agendas, not governments. The work you do here is real, and the impact is measurable. (read more about our impact )
• Technology: you'll get the right hardware and the right software you need to do your best work.
• Learning & Development: we invest in your growth because sharp people make us better. Proton is one of the fastest ways to accelerate your career because you'll be thrown into real challenges, with real ownership, from day one.
• Employee Benefits: your wellbeing isn't an afterthought. We offer strong health coverage, solid retirement options, generous leave, and wellness support so you can bring your best self to work every day.
• Stock Options: at Proton, we all have the opportunity to be owners of the company. From day one, you have a real stake in what we're building. When Proton wins, you win.
• In‑Person
  
  Collaboration:
  
  Amazing things happen when passionate, smart, and purposeful people get together in the same room. With offices across…