Senior Software Engineer | Voice | Full-Stack

Title: Senior Software Engineer | Voice | Full-Stack Location: London MEET DEEPL DeepL is a global AI product and research company focused on building secure, intelligent solutions to complex business problems. Over 200,000 business customers and millions of individuals across 228 global markets today trust DeepL's Language AI platform for human-like translation, improved writing and real-time voice translation. Founded in 2017 by CEO Jaroslaw “Jarek” Kutylowski, DeepL now has around 1,000 passionate employees and is supported by world-renowned investors including Benchmark, IVP, and Index Ventures. Our goal is to become the global leader in trusted, intelligent AI technology, building products that drive better communication, foster connections, and create a meaningful impact. To achieve this, we need talented people like you to join our journey. If you’re ready to shape the future of AI and grow your career in a fast-moving, purpose-driven environment, DeepL is your next destination. WHAT SETS US APART What sets us apart is our blend of cutting-edge AI technology, meaningful work, and a culture where people truly thrive. We’re a team of innovators, researchers, and creators driven by a shared purpose to unlock human potential by making work simpler, smarter, and more connected. When we share what it’s like to work at DeepL, the reactions are overwhelmingly positive. This might be because of our technology that helps millions of people and businesses communicate and work better every day, or because of the trust, curiosity, and care that shape our culture. What we know for sure is this: being part of DeepL means joining a team dedicated to innovation, growth, and well-being. Discover more about life at DeepL onLinkedIn and our Blog MEET THE TEAM BEHIND THIS JOURNEY DeepL is not just a translation tool; we are building the Operating System for Global Communication. We are the rare AI company that builds the entire stack in-house: from training next-gen LLMs on our own NVIDIA DGX SuperPODs to delivering real-time Language AI to over 300 million users and 200,000+ businesses globally. You will join DeepL Voice, the team defining the art of the possible for real-time interpretation. While our Translation engine conquered text, Voice is conquering the physical world. We are building the "Universal Translator"; enabling fluid, real-time conversations for frontline workers, global meetings, and enterprise teams. This is a 0-to-1 engineering environment. We successfully launched our first customer-facing features in late 2024, but we are just getting started. We are tackling the hardest problems in AI interaction: How do you eliminate the "flickering" effect of unstable transcripts? How do you chain chunked inference to achieve sub-millisecond latency? How do you deliver a seamless audio stream that feels natural, not robotic?. You will work in a dynamic, cross-functional squad alongside Researchers, Product Managers, and Designers. We are not just wrapping an API; we are building the proprietary models, the streaming architecture, and the user interfaces that allow the world to speak without barriers. YOUR RESPONSIBILITIES - A "0-to-1" Builder Mindset: You thrive in ambiguity. You don't need a roadmap to build; you need a problem. You are comfortable prototyping a new feature in the morning and refactoring it for scale in the afternoon. - Product Obsession: You care about the flow of the conversation. You understand that "99% accuracy" means nothing if the audio arrives 3 seconds late. You optimize for the human experience. - Ship End-to-End Features: Build and deploy impactful features across the entire stack, from high-performance frontend UIs to streaming audio services on the backend and AI inference integration. - Tackle Real-Time Complexity: Debug and resolve challenging edge cases unique to real-time communication, including sub-second latency spikes, transcript flicker, audio glitches, and unstable network environments. - Collaborate Cross-Functionally: Partner closely in a tight-knit, cross-functional squad alongside PMs, Product Designers, and AI Researchers to scope, shape, and solve hard product and technical challenges. QUALITIES WE LOOK FOR - A "Product-First" Mindset: You care deeply about the customer journey. You ask, "How does this feature help us close the next Enterprise deal?" before writing code. - Full-Stack Fluency: You're comfortable across the stack — building polished, modern UI in React and TypeScript on the frontend, and shipping backend services in Node.js/TypeScript (or a strongly transferable language, with willingness to ramp) on the backend. - Real-time: WebRTC, WebSockets, streaming architectures, latency-sensitive systems. - High Agency: You don't wait for permission. If the billing reconciliation process is slow, you automate it. If the documentation for the API is unclear, you fix it. - AI-Native Velocity: You leverage AI-powered tools (like GitHub Copilot or Claude) to accelerate your velocity and eliminate repetitive toil. You use AI for boilerplate code, test generation, and debugging, allowing you to focus your cognitive energy on high-value architectural decisions and complex problem-solving. A Note on Our Hiring Process: DeepL hires for the Company, not just a specific team. We operate a Unified Engineering Pipeline. If you pass our bar, we will match you to the highest-priority role that fits your skillset—whether that is in Core Product, Platform, Voice, or Enterprise. We prioritize "Missionaries" who want to solve the biggest problems, wherever they live in the stack . WHAT WE OFFER - Diverse and internationally distributed team: joining our team means becoming part of a large, global community with people of more than 90 nationalities. We're more than just colleagues; we're a group of professionals with a shared mission to connect diverse cultures. Our global presence is growing–we've doubled in size nearly every year, with our employees based in the UK, Germany, the Netherlands, Poland, the US, and Japan, and we continue to expand our network. - Open communication, regular feedback: as a language-focused company, we value the importance of clear, honest communication. We value smooth collaboration, direct and actionable feedback, and believe that leading with empathy and growth mindset makes us better together. - Hybrid work, flexible hours: we offer a hybrid work schedule, with team members coming into the office twice a week. This allows you to engage directly with your team and experience the unique energy of our workspace, while still enjoying the flexibility and comfort of working from home. With flexible working hours and trust in your productivity, we are in sync with your team’s general locations and time zones to foster effective and seamless collaboration. - Virtual Shares - An ownership mindset in every role. We believe everyone should share in our success, and that’s why every employee receives Virtual Shares, linking your contribution directly to DeepL’s growth and rewarding you with a stake in our future. - Regular in-person team events: we bond over vibrant events that are as unique as our team, from local team and business unit gatherings, to new-joiner onboardings, to company-wide events that bring us all together–literally. - Monthly full-day hacking sessions: every month, we have Hack Fridays, where you can spend your time diving into a project you're passionate about and get the opportunity to work with other teams–we value your initiatives, impact, and creativity. - 30 days of annual leave: we value your peace of mind. With 30 days off (excluding public holidays) and access to mental health resources, we make sure you're as strong mentally as you are professionally. - Competitive benefits: just as our team spans the globe, so does our benefits package. We've crafted it to reflect the diversity of our team and tailored it to align with your unique location, to ensure you feel supported every step of the way. If this role and our mission resonate with you, but you're hesitant because you don't check all the boxes, don't let that hold you back. At DeepL, it's all about the value you bring and the growth we can foster together. Go ahead, apply—let's discover your potential together. We can't wait to meet you! #LI-JL1 WE ARE AN EQUAL OPPORTUNITY EMPLOYER You are welcome at DeepL for who you are - we appreciate authenticity here. Our product is for everyone, and so is our workplace. The more voices we have represented and amplified in our business, the more we will all succeed, contribute, and think forward! So bring us your personal experience, your perspectives, and your background. It’s in our diversity that we will find the power to break down language barriers in the world.