Senior Software Engineer (m/f/d): AI-Native Development

Job description

Job Description We protect our customers’ digital infrastructure, keeping it secure, fast, and online, even under active attack. As a cybersecurity provider, we run high-performance systems in a genuinely hostile environment, where code quality, security, and rigorous input validation are not hygiene: they are the product. Our customers trust us with business-critical traffic, and we build and operate to the highest standards of certification for critical infrastructure. As a Senior Software Engineer (m/f/d), you will help your team design and build robust solutions for complex problems. We are looking for someone who thinks in systems, who starts from the problem, reasons about the trade-offs of the environment it will run in, and reaches for the tool that fits, rather than the one on their CV. We are constantly improving our applications and we work AI-natively: AI coding agents are part of how we spec, build, and review every day. We strongly believe in “you build it, you run it, you own it” and a “collaboration culture”, where you and the team are on the frontlines and driving the change together! Your Responsibilities Own features end-to-end, from backend service design through to the frontend slice the feature needs, in an international, cross-functional team of software engineers, QA and OPS professionals Design, validate and advocate architecture decisions for your team’s verticals, with a bias toward well-structured, service-oriented backends Work AI-natively: use AI coding agents as core tooling to move faster and raise quality, while staying fully accountable for the code you ship Drive technical discussions and decisions with your team Push toward continuous delivery, improving both the software and how we build it Write code that performs, and holds up in production under hostile, high-volume traffic, with security and input validation built in from the start Your Qualifications You think in systems. You start from the problem and the constraints, not from a favorite language. To you the difference between languages is largely syntax; what actually matters is the environment code runs in: performance, portability, compatibility, operational cost, and long-term maintenance You can explain your choices. You can walk us through a time you chose one language or runtime over another, and the trade-offs that drove the decision, and you can do the same for the frontend when a feature calls for it You’ve gone deep, not just broad. At least 5 years of intensive, hands-on coding and engineering experience — this is a senior role and not a fit for juniors — with genuine depth in at least one or two ecosystems. Our stack today is mostly PHP / Symfony, React and GraphQL; Edge systems use C, Rust and Python mostly. We care a lot about experience with Python, Go, C and/or Rust. These are parts that are being introduced to our dev department and where a significant part of our edge logic is based in, and someone who already reasons and builds fluently in them will make an outsized difference; this is a real signal for us, not a nice-to-have footnote Security and code quality are instincts, not afterthoughts. You write code that holds up under hostile, high-volume traffic; you treat every input as untrusted, validate rigorously, and understand how a weak boundary or a hot-path regression becomes an attack surface. Reliability under load is a first-class concern for you You’re fluent with AI-assisted development. You treat AI coding agents as core tooling; you know their strengths and limits, and you own the outcome (including reviewing AI-written code for exactly the security and validation gaps above) You reason comfortably about the whole picture: APIs, services, data, and the frontend the feature owns; you don’t stop at a language boundary You're at home on Linux systems, and CI/CD pipelines, containerization (Docker), and deployment considerations are a natural part of how you think about shipping software, not foreign territory Curious by default; you like to validate ideas hands-on with POCs and RFCs At home in an agile team with structured requirements, and quick to learn You speak and write English fluently