Senior Back End Engineer

Liminal is building the future of generative AI security—bringing safe, reliable AI to regulated industries. We're a revenue-generating, well-capitalized startup backed by one of the top-performing venture studios in the U.S.

As a Senior Back-End Engineer, you’ll take ownership of core infrastructure powering our AI security platform, especially the Liminal Engine and SDK developer experience. You'll collaborate across the stack to design scalable, secure systems that serve real customers in regulated environments. This role is a high-impact, early-stage opportunity for an engineer who thrives on building foundational systems and solving real-world problems with clean, pragmatic code.

• Design and implement critical back-end features and services, focusing on performance, reliability, and security.
• Build and maintain APIs, business logic, and core services using TypeScript (Node.js + Express) and Python (Litestar).
• Collaborate across engineering, product, and design to shape requirements and architect clean solutions.
• Own quality through unit, integration, and automated tests—striving for correctness, maintainability, and trust.
• Monitor and improve performance, scalability, and cost—profiling bottlenecks and optimizing as needed.
• Proactively identify and mitigate security vulnerabilities in code and system architecture.
• Write technical documentation (APIs, internal tooling, design decisions) that enables velocity and reuse.
• Participate in and help lead code reviews, contributing to a culture of continuous improvement.
• Help triage and resolve production issues, including contributing to incident response and patching workflows.
• Stay current on backend trends, infrastructure tooling, and security best practices—and bring that learning back to the team.

• 4+ years of software engineering experience on a product team shipping real-world systems.
• Proficiency with TypeScript and Node.js in production environments (Express or similar frameworks).
• Solid grasp of API design, async programming, and system performance fundamentals.
• Familiarity with GCP, AWS, or Azure, including containerized and serverless deployments.
• Understanding core security practices: authentication, encryption, secret management, etc.
• Experience with Docker (and ideally AWS ECS), CI/CD pipelines, and Git workflows.
• Strong debugging and troubleshooting skills for distributed systems.
• Experience collaborating in Agile teams, participating in planning, reviews, and team retros.
• Excellent communication skills, capable of collaborating across disciplines and communicating tradeoffs.
• Passion for building clean systems and solving real customer problems.
• A habit of tinkering, reading, or shipping outside work—you treat engineering as a craft, not just a job.

• Have built or contributed to SDKs, internal dev tools, or platforms used by other engineers.
• Bring experience in secure systems design or regulated environments (e.g., HIPAA, SOC 2).
• Have led major projects or mentored other engineers (regardless of title).
• Contribute to open source, write technical blogs, or enjoy sharing your learning.

• $130k - $150k annual salary based on experience + equity participation

• We are kind. We assume positive intent, celebrate co-workers' success, avoid toxic behaviors, and call out bad acting when we see it.
• We earn trust by being authentic, humble, and empathetic. Empathy is the cornerstone of building trust, and trust is a requirement in a world that is certain to be full of change.
• We are fearless, bold, honest, direct, and candid. We dare to challenge assumptions and push boundaries, and are not afraid when someone challenges us. If we make mistakes, which we will, they are unique and good opportunities to learn.
• We value discourse, not dissonance. Constructive discourse is exceptionally healthy and desirable. Expect to be challenged and rise to the occasion! Create space for the best ideas to rise to the top and let data be the ultimate decision-maker, not emotion.
• We seek understanding, not consensus. As leaders, we stand firm in our informed convictions until data overturns them. It’s healthy to disagree, but we commit to the outcome.
• We are owners. We empower each other to solve problems and take the initiative to meet our goals. We are purposeful and intentional in our thinking and know that we are individually accountable for our impacts on the company's results.
• We are curious and passionate about learning and constantly seek opportunities to grow and develop. Our space changes daily, and we adapt and mature with it.

Liminal is an equal-opportunity employer, and we value diversity at our company. We don’t discriminate based on race, religion, color, national origin, gender, sexual orientation, age, marital status, veteran status, or disability status.