Research Engineer / Software Engineer (backend)

At XBOW, we're redefining the future of cybersecurity by building the world's first autonomous pentester, powered by AI. Today, the gold standard for securing software systems is human pentesters, but with the rise of artificial intelligence, we're stepping up to scale offensive security to meet the ever-growing demand. AI is transforming the landscape of both cybersecurity and cyberattacks. While millions of people without security expertise are creating software, bad actors are using AI to launch more effective attacks. XBOW fights back with AI-driven superpowers, enabling security teams to stay one step ahead. Our autonomous AI solves 75% of web app security benchmarks with zero human intervention—and at superhuman speed. What makes XBOW truly unique? Like human experts, it forges creative attacks, adapts its learnings, and continuously works to find vulnerabilities faster than anyone ever could. We're not only simulating threats—we're also finding and responsibly disclosing real-world vulnerabilities, ensuring organizations can fix issues before they're exploited. XBOW isn't just a tool; it's a transformative force in the secure development lifecycle. Backed by Sequoia Capital and a team that includes the creators of GitHub Copilot and GitHub Advanced Security, XBOW is not just keeping up with the times—we're shaping the future of cybersecurity. Our mission is simple: to defeat the bad actors before they strike, using AI to revolutionize how we approach offensive security. We're building something that must be built, and we're the team to do it. Join us in shaping the next frontier of autonomous security. Your Role: Research Engineer (backend) We're looking for a Backend Research Engineer who's passionate about building scalable systems and solving hard problems in ambiguous environments. In this role, you'll design and implement the distributed infrastructure that powers our core engine. You'll work across services written in TypeScript and Kotlin (no worries if you haven't used these languages—we care more about your fundamentals and your willingness to learn), and deploy everything on AWS. You'll be joining a small team of superstars that's shipping quickly and operating with high trust. This is a role for someone who loves to own open-ended problems and figure things out—whether that's designing fault-tolerant systems, scaling distributed architectures, or debugging hairy production issues. If you like being at the intersection of deep tech and real-world impact, you'll feel right at home. What You'll Do Design and build distributed backend systems that scale reliably and securely Work in TypeScript and Kotlin (and pick them up quickly if you haven't used them before) Deploy and operate services in AWS Own problems end-to-end—from design through deployment to production support Navigate ambiguity and help define how we build as much as what we build Collaborate closely with teammates across the stack, including AI researchers, Security researchers and frontend engineers Who You Are Experience building and operating scalable, distributed systems Comfort working in a fast-moving, early-stage environment Strong problem-solving skills and the ability to work with incomplete information Familiarity with AWS or similar cloud platforms You have deep experience designing and optimizing relational databases (we use Postgres), and you know how to structure data for both performance and clarity. You're comfortable working with infrastructure as code (e.g., Terraform or CDK) and see infra as part of the engineering system—not something separate from it. Eager to learn new tools, languages, and technologies as needed A thoughtful communicator who values clarity and simplicity Comfort working in a fast-paced, early-stage startup environment Bonus Points Experience with event-driven architectures, message queues, or async workflows Background in systems programming, networking, or performance tuning Experience with hybrid deployments (cloud + on-prem) and know how to build resilient systems that handle the complexity of mixed environments. Experience working in an early stage startup Prior experience building developer tooling or security products

XBOW is redefining the future of cybersecurity by building the world's first autonomous pentester, powered by AI. They are backed by Sequoia Capital and a team that includes the creators of GitHub Copilot and GitHub Advanced Security.