Senior Software Engineer | API Enterprise

Title: Senior Software Engineer | API Enterprise 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 the API Enterprise team. We sit at the intersection of DeepL's API platform and our Enterprise ecosystem. Whereas the Core team obsesses over the self-service developer journey, our focus is on enterprise customer adoption: the usage insights, cost controls, RBAC , compliance, and data residency capabilities that enterprise IT and security teams depend on. We work hand-in-hand with a wide set of stakeholder teams to make DeepL's API the obvious and safe choice for global enterprises. We are shifting gears. We are moving from "Software-First" to "Product-First." We don't hire engineers to just close tickets or optimize algorithms in isolation. We hire Missionaries — builders who obsess over the Why before the How. You will contribute across the stack, shipping features that create delightful, frictionless experiences for both external developers and internal engineering teams. YOUR RESPONSIBILITIES - Drive Enterprise API Adoption: You will own the features that turn enterprise interest into deep, durable adoption. Examples include usage insights, cost and consumption controls, and the governance tooling that lets large organizations understand and manage how they use DeepL's APIs - Build for Governance & Compliance: You will design the controls enterprise IT and security admins rely on (roles and permissions, projects, data residency, and audit-ability), making DeepL the compliant default for regulated, global organizations - Guardianship of Quality & Production Reliability: You will own your services end-to-end, including participation in the API on-call rotation, with a shared goal of taking our public API to four nines of reliability. You will implement strong contract testing, monitoring, and SLOs, preventing breaking changes and security vulnerabilities before they reach our enterprise customers - Architect Across the Enterprise Ecosystem: You will work deep within DeepL's existing technical and organizational structures, navigating dependencies across different areas and many stakeholder teams to ship cohesive, reliable enterprise capabilities QUALITIES WE LOOK FOR - An "Enterprise-First" Mindset: You treat enterprise IT and security admins as your primary users. You understand that earning their trust means clear governance, predictable cost control, robust compliance, fast response times and data residency. You're a strong communicator who's comfortable owning product decisions and implementing them - Backend Mastery at Scale (C# / . NET): You have deep expertise designing scalable backend systems, RESTful APIs, and distributed architectures, primarily in C# / . NET, and you've worked with high-scale distributed systems in production. Strong API design fundamentals and system design are core to how you work. Roughly 80-90% of the work is backend; working on the frontend (React/TypeScript) is a welcome plus, not a requirement - Enterprise Platform Fluency: You bring hands-on experience with the building blocks of modern enterprise APIs (MCP, CLIs, and OAuth) and know how to wield them to build secure, extensible integrations - Cross-Team Leadership: You have a track record of leading projects across multiple teams. You can align with different areas and other stakeholders, manage cross-team contracts and dependencies, and keep complex, interconnected systems coherent - Extreme Ownership & Operational Excellence: You own your services end-to-end (production operations, incident response, and on-call) and you're motivated by pushing reliability toward four nines. You write comprehensive tests, learn from incidents, and treat mature SLOs as a core engineering feature - AI-Native Velocity: You leverage AI-powered tools (like Claude Code, Codex or GitHub Copilot) to accelerate delivery so you can focus your energy on high-value architecture and complex problem-solving - Bonus points if you have: a track record of zero-downtime migrations on live systems; experience with metering, quota, or usage-data systems; worked in a compliance environment (SOC 2, ISO 27001, C5, or similar) 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! 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.