Full Stack Engineer

Full Stack Engineer at Cantina About Spearbit & Cantina: We're building Cantina, an AI Security Platform that secures the world's code. Originally the "GitHub for Security" — connecting security researchers with the projects needing their expertise — Cantina has evolved into a multi-product platform spanning Apex, Clarion, and Cantina Bounties. It has powered major competitions and serves many of the leading projects in Web3, supporting collaborative security reviews, public and private competitions, bug bounty programs, AI-driven code analysis, and a security operations center (SOC) that monitors, triages, and responds to live alerts and threats. Similar to how cloud-security startups emerged previously, Cantina aims to be the definitive code-security platform for the future. The Opportunity: We’re looking for a Full Stack Engineer to help us design, build, and scale our core products. This is an opportunity to have a real impact on our technical direction and product roadmap while working alongside a team of builders who thrive on curiosity and collaboration. We have multiple positions available and are open to a variety of experience levels, including recent graduates. What matters most is a strong foundation in software development, a willingness to learn quickly, and excitement about working with Agents. What you'll do: Full ownership of features from design, implementation, all the way to release and monitoring while in production. We put strong emphasis of individual ownership and protectiveness. Build and maintain full-stack features end to end — from Next.js/React interfaces to tRPC APIs and Prisma-backed data models. Work on AI agent workflows: integrating the various agentic SDKs, orchestrating sandboxed agent workloads, and designing the tooling that lets agents safely act on security data. Ship integrations with the security and developer ecosystem (webhooks, third-party detection sources, notification channels) with end-to-end type safety. Collaborate closely with designers, PMs, and engineers to deliver seamless, trustworthy user experiences. Write clean, well-tested, maintainable code across the stack, and help uphold our security and quality bar. Participate in code reviews, architecture discussions, and knowledge sharing. Stay current with web, AI, and Web3 trends, and bring the best ideas back into the product. What we’re looking for: Hands on experience building with LLMs and AI agents is a must. We are an AI native team, trying to stay at the edge of the latest developments. This means you’ve got experience with AI tools, workflows, tool usage, prompt design etc. Strong programming fundamentals, ideally in TypeScript/JavaScript (Python, Rust, or Go experience is a plus). Familiarity with modern frontend frameworks — React and Next.js especially. Backend experience building APIs and services (Node.js; experience with tRPC, REST, or similar). Understanding of relational databases and ORMs (PostgreSQL, Prisma, or equivalents). Hands on experience with cloud systems such as Vercel/AWS/Railway/others A self-starter mindset, comfortable navigating ambiguity in a fast-paced startup. Strong communication and collaboration skills — we're a fully global team. Prior startup, internship, or substantial project experience is a plus. Experience in the security domain is a plus Benefits Competitive salary and performance-based compensation opportunities Opportunity to work in an early-stage startup with a talented and passionate team.