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Salary: USD 135,000 - 165,000 / annual
RunSybil, founded in 2023, is building Sybil, an AI-driven pentester that discovers vulnerabilities before they're exploited. The company was founded by Ari Herbert-Voss and Vlad Ionescu and is backed by strong investor support with early customer traction. The team includes experts from OpenAI, Meta, Mandiant, Palantir, Cruise, Trail of Bits, and Aptiv.
As a Software Engineer I, you will ship customer-facing features from your first weeks, working directly alongside senior engineers and founders. You'll build and extend the agentic systems that power Sybil, working primarily in Python with TypeScript and React across the stack. Your code goes to production immediately—there is no shadow work here.
Key responsibilities include shipping customer-facing features end-to-end from first commit through production with close review and support from senior engineers; building and extending agentic systems using Python, TypeScript, and React; using LLMs as a core part of your workflow including prompting, evaluating generated code, and building tooling; owning small projects yourself including scoping, proposing approaches, and seeing them through; debugging real issues in production systems that customers rely on; contributing to technical design discussions and code reviews; and learning offensive security on the job from world-class practitioners.
The ideal candidate has strong Python fundamentals and comfort with data structures, evidence of shipping software in any setting (internships, projects, research, or personal work), a habit of taking initiative, hands-on experience coding with LLMs with good judgment about when to use them, fast and honest communication, coachability, and familiarity with modern JavaScript and React as a plus. The company values people with a trail of side projects, open source contributions, and self-taught solutions to problems they care about.
