Senior Back End Engineer

Liminal

98d

About The Position

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.

Requirements

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.

Nice To Haves

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.

Responsibilities

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.