We've been quietly reinventing how the world thinks about software reliability, and we're just getting started! At Antithesis, we start at the foundations – we run entire software systems inside a deterministic simulation and break them in every way imaginable. Every issue then comes with a perfect reproduction, so you can identify root causes fast instead of spending days trying to recreate what went wrong.
The rise of AI-generated code has made this work more urgent than ever. Agents can write code faster than any human, but speed doesn't matter much when the output is buggy, stuck in review, or slipping through undetected. The verification bottleneck is real, it's growing, and solving it is one of the most consequential problems in software right now. That's what you'd be working on.
We're well-funded and deeply technical, the kind of place where the hardest problems get the most attention and the best ideas win regardless of who has them. If you want to do work that actually moves the needle on how reliable software can be, keep reading.
We're looking for engineers in the Senior to Staff levels to build the future of autonomous testing. No matter your particular field of experience, if you've been ambitiously building complex software and think you could be a fit; drop us a note.
In this role you will be part of the team that maintains our open-source project Bombadil (https://github.com/antithesishq/bombadil). This includes working with the specification language and verifier, Chromium automation, advanced property-based testing, frontend development, and much more.
Our team spans CS degrees, philosophy, mathematics, and everything in between, or nothing formal at all. What everyone shares is a high bar for engineering quality. We work in-person because it's how we build trust and tackle hard problems together.
Location: This position is 5 days in the office in London, UK.
Ship confidently and free your engineering team to focus on creating business value. Antithesis enables you to find and eliminate bugs that cause system downtime and difficult-to-fix correctness issues.
Our platform combines AI with advanced testing methodologies to thoroughly explore distributed systems and find the bugs that other tools miss. The platform perfectly reproduces bugs and the conditions that led to them, dramatically reducing the time required to debug systems and enabling engineers to validate fixes with 100% certainty.
Instead of having engineers (or AI) write more test cases, the platform enables property-based testing where you define desired outcomes. Our autonomous AI-powered testing engine explores millions of code paths in parallel and smartly injects the kind of faults your code routinely experiences in hostile production environments. No more testing only the "happy path" and missing the issues that will haunt you in production.
