Product Engineer

Why us

We started CoLoop in 2020 while still at university. We survived multiple cofounder breakups and all sorts of other near-death experiences. Despite that we built our first product to $1M ARR, and then killed it after realising the opportunity was too small and we didn't have real PMF. We spent six months pivoting, and through that process came to understand just how important customer research is to finding a winning strategy. So we built a product to make it faster, cheaper, and better.

We don't tell you this because we think suffering is something to aspire to. We tell you because if you're evaluating where to work next, you should know who you'd be working with. We are not going to sell early, get comfortable, or lose interest. This is everything to us.

We also take seriously that you're trusting us with your time. Three people who've worked at CoLoop have gone on to become YC founders. When you're here, we'll share everything we know and everything we learn along the way. All we ask is total commitment.

About the role

You'll spend most of your time understanding customers, thinking about what to build, and shipping. Talk to customers directly, sit with the team members who interact with them daily, watch the recordings (in CoLoop). AI handles a lot of the raw building now, so the bottleneck is taste, context, judgement, and polishing.

At CoLoop, engineers own the full cycle. There are no product managers. You gather context from customers and teammates, decide what to build, build it, launch it, measure the impact, and iterate. We track individual attribution in PostHog.

The structure is flat. Influence is earned through skill and context. We'd rather you make a wrong call than wait to be told what to do.

We run 5-6 week company-wide sprints with a decentralised approach and minimal meetings. We're in our Oxford Circus office as often as possible (2 days min per week).

Your work will span three main areas:

Making the product feel exceptional. CoLoop is used daily by researchers at some of the best companies in the world. You'll own UI/UX improvements that make the product faster, clearer, and more delightful to use.

Growing the product. We're building a product-led motion. You'll design and ship in-app growth experiments, lead magnets, onboarding flows, and activation loops that move conversion and retention numbers.

Building for our customers. Some of the world's best research teams rely on CoLoop. You'll build bespoke features and integrations that make them wildly successful, and turn those into product capabilities that benefit everyone.

What we're looking for

• You care deeply about the end user's experience. You notice when padding is off, when a loading state is missing, when a flow has one too many steps.
• You're commercially minded. You think about what moves revenue, not just what's interesting to build.
• You have an artisan's mindset toward your craft. You can explain what makes Linear great, both as a company and product. You know that AI makes good engineers faster but doesn't replace taste and craftsmanship.
• You know when to cut corners and when to be rigorous. Move fast at the edges, build carefully at the core.
• You want to get on call to fix a gnarly bug even though somebody else caused it.
• You recognise you have blind spots and want other people to point them out, and will happily return the favour.

Must-haves

• 2+ years full-stack experience building web applications.
• Strong React and TypeScript.
• Comfortable using AI coding tools (e.g. Claude Code) as part of your daily workflow.
• Fluent English.

Nice-to-haves

• You've worked on PLG or growth engineering.
• You've been a founding engineer at a high-growth company, or founded one yourself.
• You've contracted or consulted on projects for enterprise-scale clients. People who've operated end-to-end for paying customers tend to think commercially, and that matters here.

No AI experience needed

Our product is AI-native, and you'll be working alongside engineers who build AI systems every day. The day-to-day for this role is product work, not AI work. But you'll absorb a lot by proximity, there's scope to take on AI projects over time, and if you're great at it, to move into that kind of work entirely.

What you get

• You work directly with the founders and founding team on a daily basis.
• You join a tight-knit team of engineers: physics PhD, hackathon winner, and more.
• You work alongside engineers building cutting-edge generative AI, including our multi-agent system for qual content analysis. You won't be siloed from that work.
• You become part of a community of top technologists in London. We regularly host dinners, hackathons, and CoLoop CoWorking from our office most Saturdays.

How to apply

• 1-line introduction about yourself.
• 1-2 lines on what you've built and what you took away from it.
• A URL to a live project, repository, or open source contribution you made.
• 1-2 lines on your interest in CoLoop and how you'd contribute.

Interview process (~1–2 weeks)

1. Screening interview (30 min)
2. Technical interview (60 min)
3. In-person contract
   1. 1 week trial (preferred)
   2. 1 day trial (if unable to do 1 week)
4. Decision

If you're excited about this role but don't meet every requirement, we'd still love to hear from you. If you'd like to meet the team, we host CoLoop CoWorking from our office most Saturdays!