Join Assert Labs

We are a team of engineers and researchers with an ambitious mission: to move the world toward error-free software. We're doing this by building tools to autonomously test and analyze code. We are backed by Accel, Guillermo Rauch (Vercel), Thomas Wolf (Hugging Face), David Cramer (Sentry), Charlie Marsh (Astral), and a number of other open source developers, machine learning researchers, and entrepreneurs. If you wish to learn more, read here about our mission and values.

Our Culture

• -We are assembling a lean group of generalists. While we welcome experience, we're primarily looking for creative, curious problem solvers with a keen interest in open-ended, technically challenging problems.
• -We want to work with people who care deeply about the mission of the company and enjoy the work required to achieve it.
• -We work in person in our office in San Francisco. We believe that having a community is critical for learning, growth, and camaraderie. We pay generously for relocation assistance.
• -We invest heavily in our team's growth. We sponsor conference attendance (NeurIPS, ICML, RustConf, PyCon, etc.), run an internal paper reading group, and encourage blogging/publishing research. If there's something that will help you grow as an engineer or researcher, we actively want to support it.
• -We believe in compensating exceptional talent exceptionally well. We benchmark our compensation against the top 90th percentile for each role, and we're committed to working with candidates we're excited about to ensure they are excited too.
• -We have an academic as well as competitive spirit. We enjoy thought exercises, math puzzles, intellectual inquiry, and vigorous debates. Outside of working hours we enjoy playing board games like Chess, Go, and Diplomacy.

Role: Systems Engineer

Build reliable, low-latency, and isolated execution environments. Design and implement highly parallel execution environments that can safely run untrusted code at scale, with strong isolation guarantees, precise resource control, and low latency. Our systems execute large numbers of isolated workloads while maintaining strict security boundaries and predictable performance characteristics. This infrastructure forms the foundation of our ability to analyze, test, and understand software behavior at scale.

Responsibilities

• -Design and implement zero-trust execution environments using WebAssembly and hardware virtualization
• -Build reproducible, declarative infrastructure using Nix/NixOS for deterministic builds and deployments
• -Develop high-performance Rust systems that leverage modern CPU features and zero-copy architectures
• -Create secure sandboxing solutions that balance safety, performance, and resource utilization

Qualifications

• -Expertise in Rust and systems programming, with strong understanding of memory safety and zero-cost abstractions
• -Experience with WebAssembly, particularly runtime implementations, sandboxing, and security boundaries
• -Knowledge of modern virtualization technologies (e.g., KVM, hardware-assisted virtualization, unikernels)
• -Familiarity with declarative infrastructure and reproducible builds (e.g., Nix)

Interview Process

Our interview process is designed to be unusually thorough yet efficient, respecting our time as well as yours. We occasionally accelerate the process or skip steps for candidates.