Product Engineer
Confirmed on the employer's own hiring board on Oct 6, 2026. First seen by Alion on Aug 19, 2026.
Our mission is to build the operating layer for mobile development. The first part of that journey is to build the best tool to help teams catch mobile bugs, by deploying agents using computer vision on real devices.
We’ve secured over $3m in funding from Concept, Evantic, and Weekend Fund, and operators behind companies like ElevenLabs, Hugging Face, OpenAI, and Linear.
We’re still early, but we’re already relied on daily by cutting-edge companies like Granola, Gopuff, Slingshot AI, Praktika, Clove, Scope AI, Nexos, Morse, and many more.
Learn more about the Semaloop team via our Candidate Hub.
Who you are
An engineer who not only writes clean and reliable code, but has great product instincts and loves jumping on calls and threads with customers. Our stack changes fast, so strong fundamentals matter more than experience in a particular language or framework.
A true problem solver and builder, who enjoys working together around a whiteboard and reasoning from first principles. You thrive on the pace and ambiguity of working in a startup environment.
Experienced taking ML concepts from "works on my laptop" to real production systems. You know about the unglamorous parts, like data pipelines, evals and maybe even statistics.
Calm when days move quickly and priorities shift. You can decide what matters most, make progress without being blocked, and keep shipping while the product takes shape.
Proficient with AI-assisted coding tools, but you still own the code that's committed. You care about quality, and you want to spend more time on the interesting problems.
Someone who enjoys working in-person; we’re based in Old Street and typically in 4 days a week.
What you’ll be building
Our engineering team is pioneering the path from agents that test applications to agents that can autonomously verify mobile software is working correctly. With a small team, it means you’ll own projects end-to-end and work across the full software stack (frontend + backend + infra).
Day to day, that spans:
Architecting cutting-edge AI agents using a mixture of external, open source and proprietary multimodal models.
Developing internal eval benchmarks and aggregating datasets to measure and improve agent performance.
Working with frameworks like Appium and pymobiledevice3, as well as reverse-engineering mobile device communication protocols so that we can develop our own in-house tooling.
Scaling our physical device farm through in-house automation, a genuinely unique part of the role.
Integrating with platforms like GitHub, Slack and Linear, as well as emerging protocols such as MCP.
Your impact won’t stop at engineering: you’ll work on initiatives across the business, help our go-to-market machine, support our customers and craft our product roadmap.
We know that amazing talent comes from all walks of life. If you find yourself feeling energised reading the above, whether you look like a fit on paper or not, please get in touch!
What we offer
Joining an early-stage company always comes with a level of risk, but we don't think our early team should have to compromise on everything else. That's why we pay well and offer strong benefits, if we do well, we want everyone to share in that success.
£110,000 - £130,000 + equity
28 days holiday + bank holidays
Private medical & dental for you and your dependants (Bupa)
Pension matched up to 10% (Penfold)
Generous parental leave
Life assurance, critical illness & income protection
The story so far
If you’ve made it this far, here’s a little more about our journey and the exciting mission and vision driving it.
From humble beginnings with a small device farm in Charlie’s shed, we saw first-hand how agentic coding unlocked many barriers to building apps, but ensuing that they run reliably was still incredibly painful. Whether at early-stage startups or tech-giants, flaky tests blocked releases and was the real bottleneck in getting new features into customer’s hands.
We’re on a mission to change that by building agents that test apps like humans do: through sight, sound and touch. We believe developers shouldn’t need to maintain special APIs, accessibility IDs or integrate new libraries, but rather whenever a new build is shipped all of the important workflows are verified before reaching users, automatically, by an agent. If there’s a bug, those developers shouldn’t need to talk about flaky tests, but rather see that their coding agent has already received the full context in order to fix exactly what’s broken. That means an end to manual testing, and hours of time back per day for developers.
Our vision is to build the go-to operating layer for mobile that not only cuts across code verification and testing, but also all other friction points in the mobile journey: writing the app, shipping it, monitoring performance, learning from users, growing revenue, and ensuring everything is secure. We think we’re best placed to do this with our agentic multimodal approach.
This effort spans ML, real physical hardware, and software development. If you’re excited by the idea of teaching computers to understand, reason and interact with digital interfaces, you belong on this mission with us. We’re assembling a small all-star team here in London, with the ambition to truly change how mobile software is made.