Join Proton and build a better internet where privacy is the default
At Proton, we believe that privacy is a fundamental human right and the cornerstone of democracy. Since our inception in 2014, founded by a team of scientists from CERN, we have dedicated ourselves to providing free and open-source technology to millions worldwide, ensuring access to privacy, security, and freedom online.
Our journey began with Proton Mail, the largest secure email service globally, and has since expanded to include Proton VPN, Proton Calendar, Proton Drive, and Proton Pass. These tools empower individuals and organizations to take control of their personal data, break away from Big Tech’s invasive practices, and defeat censorship. Our work impacts hundreds of millions of lives, from activists on the front lines defending freedom to leaders in governments protecting sensitive information. In some cases, Proton’s services have even been instrumental in saving lives by enabling secure and private communications in high-risk situations.
Proton is a profitable company that does not rely upon VC funding, supporting over 100 million user accounts with a growing team of over 500 people from over 50 different countries, from the world's top companies and universities. We value intelligence, learning potential, and ambition in our hiring process. Adaptability is key as we navigate uncharted territories and redefine how business is conducted online.
Hiring at Proton is highly selective, with less than 1% of candidates hired. We believe smaller teams of exceptional talent will always prevail over larger teams with lower talent density. You will have the opportunity work with many of the world's top minds in their fields, ranging from former international math and science olympiad winners to chess champions.
We have a global mindset and big ambitions but remain a start-up at heart. We value empowerment and flexibility and keep our structure flat to keep moving fast and avoid unnecessary politics. Tired of blending into the crowd? Join us and do work you can truly be proud of. Check our open-source projects here!
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.
We are seeking a Fullstack Applied AI Engineer to build and maintain the complete AI infrastructure powering Lumo's privacy-first platform. You'll own the full stack from database to frontend, implementing AI tool calling systems, privacy-preserving search, and encrypted services while ensuring 99.9% uptime for millions of users.
This role combines AI/ML engineering, backend development, site reliability, and frontend integration using Rust, PHP, and modern web technologies to deliver scalable, encrypted AI experiences.
AI Systems Development
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.
As a Fullstack Applied AI Engineer at Lumo, you'll own the complete technical stack powering privacy-first AI experiences, ensuring millions of users can rely on Lumo for their most sensitive conversations with complete confidence in both AI capabilities and privacy protection.
What We Offer
Our Commitment to Diversity and Inclusion
At Proton, we believe diversity drives innovation and strengthens our mission to provide privacy as a default for all. We are committed to fostering an inclusive environment where all individuals, regardless of race, ethnicity, gender, age, sexual orientation, physical ability, or socio-economic background, feel valued and empowered. We strive to create equal opportunities, promote open dialogue, and support continuous learning to ensure every voice is heard and respected.
If you need any extra support or reasonable adjustments during the hiring process, please let your talent partner know.
Candidate Privacy Notice
When you apply for a position, refer a candidate, or are considered for a role at Proton Technologies AG (Proton, we, us, or our), your information is stored in Greenhouse, in accordance with their Service Privacy Policy. This information is used to evaluate your suitability for the posted position. We also retain this information for consideration for future roles that you may apply for or that we believe may align with your background and skills.
If we no longer have a legitimate business need to process your information, we will either delete or anonymize it. Should you have any inquiries about how we use or manage your information, or if you wish to access, correct, or delete your data, please contact our privacy team at [email protected].
Proton does not accept unsolicited resumes from any sources other than directly from candidates. We will not pay a fee for any placement resulting from an unsolicited offer, even if the candidate is subsequently hired by Proton.
To learn more about our privacy policy, please visit our privacy policy page.
#LI-ONSITE
By applying at a position at Proton AG (“Proton”, “we”, “us”), you understand that your personal data is processed according to the following privacy policy and agree with it. This policy states (i) what data we collect, (ii) the use we make of such data, (iii) the safeguards we put in place to protect your data and (iv) your rights as data subject. This Privacy Policy is complementary to our general privacy policy to the extend applicable when visiting our website. Legal Framework Proton AG is a Company formed under Swiss law and whose Headquarters are located at Route de la Galaise 32, 1228 Plan-les-Ouates, Switzerland. For all questions, you can reach us at [email protected]. We are subject to the Swiss Federal Act on Data Protection (“FADP”). We are also GDPR compliant. The designated representative of the Company in the European Union (notably for the purpose of art. 27 GDPR) is Proton Europe Sàrl, Rue de Grünewald 94, L-1912 Luxembourg. Data collection and usage Your personal data are processed for the purposes of managing our recruitment-related activities, which include setting up and conducting interviews and tests for applicants, evaluating, and assessing the results thereto, and as is otherwise needed in the recruitment and hiring processes. Such processing is legally permissible under Art. 6(1)(f) of Regulation (EU) 2016/679 (General Data Protection Regulation, “GDPR”) as necessary for the purposes of the legitimate interests pursued by us, which are the solicitation, evaluation, and selection of applicants for entering a contractual relationship. Your personal data are retained by us for an initial period of 720 days (“Initial Period”). 2.1 Upon application via our Career page When applying to a position at Proton, you provide us with personal data such as name, surname, date of birth, address, e-mail address, CV, etc., which we save in our Recruiting Database (“Database”, see below) and process according to this privacy policy. 2.2 Upon sourcing or recommendation If you are sourced by us and added manually to our Database, the personal data is obtained from public sources, such as LinkedIn. If you are referred to us by a third party for potential employment, the personal data added to our Database is that provided by said third party, and/or data available publicly. In all cases, upon inclusion in our Database, you will receive an email informing you of your inclusion and of the processing of your personal data. 2.3 At the end of the Initial Period At the end of the initial period, you will receive an email asking for your permission to extend the period of retention of your personal data, for the purpose of optimising our processes and propose subsequent positions that might be fit for you. If you give us your consent, we will be able to store and process the data for another 270-day period. If you don’t consent, your profile and related data will be deleted from our Database at the end of the initial period. Data Processor Our Database is operated by Greenhouse, according to their privacy policy and terms of service. Your personal data is thus shared with Greenhouse Software, Inc., a cloud services provider located in the United States of America. The transfer is subject to appropriate additional safeguards, including the Standard Contractual Clauses, as issued by the European Commission. Right to access, rectification, erasure, portability, and right to lodge a complaint As a company that is complying with the Swiss FADP and the EU GDPR, your privacy is important to us, and we are committed to protecting and safeguarding your data privacy rights. You have the right to access, restrict, rectify, or delete your personal data. You also have the right to withdraw your consent at any time. In addition, you may lodge a complaint to the Swiss Federal Data Protection and Information Commissioner. We remain available via email to [email protected] for any inquiry. 5. Modifications to privacy policy We reserve the right to periodically review and change this policy. Continued consent and application will be deemed acceptance of such changes.
Please mention you found this job on AI Jobs. It helps us get more startups to hire on our site. Thanks and good luck!
Be the first to apply. Receive an email whenever similar jobs are posted.
Understand the required skills and qualifications, anticipate the questions you may be asked, and study well-prepared answers using our sample responses.
AI Engineer Q&A's