Senior Fullstack Engineer at Merchant EMEA Engineering (London)

As a Senior Fullstack Engineer, you'll own complex product and technical problems across the merchant experience, from problem definition through design, implementation, production, and ongoing evolution.

You'll:

• Design, build, and operate production systems across backend services and user-facing applications.

• Lead technically complex initiatives across areas such as merchant onboarding, analytics, recommendations, menu and order management, integrations, or merchant-facing tools.

• Translate ambiguous business and merchant problems into scalable, pragmatic technical solutions.

• Drive technical design and architecture decisions, considering scalability, reliability, maintainability, and long-term product needs.

• Own systems and initiatives end-to-end, from early discovery and design through implementation, rollout, production operations, and iteration.

• Collaborate closely with product managers, designers, operations, and engineers across teams to align on solutions and delivery.

• Support and mentor other engineers through design discussions, code reviews, knowledge sharing, and technical guidance.

• Use AI-assisted development tools effectively to increase engineering velocity, while maintaining strong judgment around correctness, security, maintainability, and quality.

• Work comfortably outside your primary area of expertise when needed to solve problems end-to-end.

How We Work

• Ownership: Senior engineers take responsibility not only for implementation, but also for understanding the problem, shaping the solution, and ensuring it works successfully in production.

• Collaboration: We work closely across engineering, product, design, data, and operations. Senior engineers are expected to help drive alignment when problems span multiple teams or areas.

• Pragmatism: We value simple and maintainable solutions that create business impact without unnecessary complexity.

• Flexibility: We care more about solving the problem than strict frontend or backend boundaries.

Our Tech Stack

Our backend services primarily use Go and Kotlin, while our frontend applications use technologies such as TypeScript and React.

We also work with technologies including Kafka, PostgreSQL, MongoDB, Redis, AWS, Kubernetes, Docker, gRPC, and modern cloud infrastructure.

Our Humble Expectations

We're looking for engineers who have:

• An AI-first mindset, with strong experience leveraging modern AI tools alongside solid engineering principles to solve problems end-to-end, independently of any specific technology stack.

• Strong experience designing, building, and operating production software at scale in backend, frontend, or fullstack environments.

• Experience owning complex features, services, or technical initiatives from problem definition through production and ongoing operation.

• A strong understanding of system design, APIs, databases, distributed systems, testing, observability, and production reliability.

• Experience making technical and architectural decisions where there are multiple valid approaches and meaningful trade-offs.

• A track record of helping other engineers grow through mentoring, technical guidance, code reviews, or knowledge sharing.

• Strong communication skills, including the ability to explain complex technical decisions clearly to both technical and non-technical stakeholders.

• Experience with a modern backend language such as Go, Kotlin, Java, and/or modern frontend technologies such as TypeScript and React.

You do not need to be equally strong in frontend and backend. We welcome different balances of experience. You might be primarily a backend engineer who is comfortable making frontend changes when needed, or a frontend-focused engineer who is happy to work with APIs and backend services.

What matters most is that you are comfortable working across boundaries to deliver the right solution.

Nice to Have

Experience in one or more of the following areas would be a plus:

• Merchant-facing or internal operational tools.

• Analytics, recommendations, or decisioning systems.

• Grocery, retail, restaurants, logistics, or marketplace technology.

• Integrations with external business systems.

• Kafka or other streaming technologies.

• Cloud infrastructure such as AWS, Kubernetes, or Docker.