Founding Engineer

Hey! We’re Semaloop 👋 Late last year, we stuck a bunch of iPhones in Charlie’s shed, connected them to a computer, and began building. Now, a few months later, we’ve secured over $3m in funding from investors and operators behind companies like Lovable, ElevenLabs, Hugging Face, Linear and Dropbox - and we’re already relied on daily by cutting-edge companies like Granola and Gopuff. Sema-who? We saw first-hand how building apps was being slowed by checks and balances. Whether at early-stage startups or tech-giants like Apple (where Rory previously worked), flaky tests blocked releases and QA slowed cycle time. Automating UI testing has been brittle and slow ever since the first smartphone came out in 2007. We’re on a mission to change that by building agents that test apps like humans do: through sight, sound and touch. By solving for the human interfaces, developers don’t have to maintain special APIs, accessibility IDs or integrate new libraries (if you’re a mobile developer, we hope we haven’t triggered you!). Instead, teams like Granola just describe how their app should work in plain English. When they ship new builds, Semaloop does the heavy lifting: verifying that the app works, and if not, figuring out what’s broken. That means an end to manual testing, and hours of time back per day for developers. Crafting a truly magical experience for developers means building some category-defining technology. That’s why we’re assembling an all-star team here in London, with the ambition to truly change how software is made. 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. The Job We can’t keep up with the demand for Semaloop! We’re looking for someone who enjoys dabbling in a little bit of everything, as well as owning their own niches, all in the backdrop of an ever-evolving industry. As a Founding Engineer at Semaloop, you’ll quickly discover this isn’t your standard full-stack job. You might find yourself building RL pipelines one day, while reverse-engineering USB protocols the next. Our edge is our eagerness to turn our hand to every task in the stack, not because we have to, but because we love to. You’ll regularly work directly with customers to help debug issues, understand their processes and shape our product roadmap. As part of the founding team, you’ll have the opportunity to shape the technical direction of the company as Semaloop scales to the next 100 customers. Whether you’re training multimodal models, or polishing user experiences, you’ll own how you manage and prioritise your time. In return, we promise to bring together the rest; a world-class team of incredible people, an endless list of gnarly technical problems and the opportunity to truly achieve your life’s best work. We’re looking for…

• An engineer who writes clean and reliable code. Our stack changes fast, so strong fundamentals matter more than experience in a particular language or framework.
• Someone who enjoys prototyping in their spare-time, and geeking out over the technical details. We're nerds at heart, and engineering is what gets us out of bed in the morning.
• Hands-on experience taking ML ideas from "works on my laptop" to real production systems. You know about the unglamorous parts, like data pipelines, evals and maybe even statistics.
• Calmness when life moves quickly and priorities shift. You can decide what matters most, make progress without being blocked, and keep shipping while the product takes shape.
• Proficiency with AI-assisted coding tools, to move faster and rapidly prototype, while still owning the code that's committed. You care about quality, and you want to spend more time on the interesting problems.

As a person, you…

• Consider yourself first and foremost, a builder.
• Get excited at the idea of working together in-person from our office in Old Street (typically at least 3 days a week).
• Love working in a startup environment (you either have experience working in a startup or can point to products/companies you’ve built yourself).
• Obsess over the customer experience, and quality in products you ship.

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! You can expect to…

• Design and develop new product features across the full software stack (frontend + backend + infra).
• Architect cutting-edge AI agents using a mixture of external, open source and proprietary multimodal models.
• Train in-house ML models via supervised and reinforcement learning.
• Develop internal eval benchmarks and dataset aggregation.
• Build and improve secure cloud infrastructure.
• Reverse engineer device communication protocols.
• Scale physical device farms using in-house automation.
• Stay connected with the latest research and advancements in the wider industry, incorporating new technology and ideas into our stack.
• Work on initiatives across the entire business, from your home in engineering, all the way to helping grow our go-to-market machine.
• Be on the front-line, chatting with and supporting our customers, and helping to craft our product roadmap.

What we offer

• 28 days of paid holiday, plus public/bank holidays.
• Market-leading private medical and dental insurance.
• Generous parental leave policies.
• Competitive salary and equity package.
• Pension contributions matched up to 10%.
• Life, critical illness, and income protection insurance.

Compensation Range: £90K - £130K