Senior Software Engineer (Fullstack, TypeScript)

Nine Elms, London - Full-time (3 days a week on-site)

Zapp is building the future of convenience with a full stack approach to on-demand essential items, 24/7, delivered in minutes. Customer obsession is at the heart of everything we do. From app users to frontline staff to store workers, we are relentlessly focused on delighting our customers. We are backed by the world's leading investors and our team has scale-up and exit experience at companies such as Amazon, Jumia, Deliveroo, Tesco, Stuart and Just Eat. If you're ready to help build the world's most customer-focused company, get in touch. We are an AI-first company. We don't just build software, we build intelligent systems. From AI-assisted development workflows to LLM-powered product features, we expect our engineers to embrace and actively contribute to how AI is reshaping the way we work and what we ship. As a Senior Software Engineer at Zapp, you will take end-to-end ownership across the full stack. You'll own everything from product features through to the infrastructure that runs them, working across a modern TypeScript-first codebase, contributing to platform reliability and security, and helping shape the engineering culture as we scale.

Responsibilities

• Design and build robust, scalable full stack systems across backend services, APIs, and client-facing applications

• Architect and manage cloud infrastructure using Infrastructure as Code (IaC) tooling such as Terraform or Pulumi

• Write and maintain efficient REST APIs and GraphQL schemas

• Define and enforce security best practices across the stack, including secrets management, IAM policies, network security, and secure SDLC practices

• Champion observability: logging, tracing, alerting, and incident response

• Integrate and build AI-powered features, including working with LLM APIs, prompt engineering, and evaluation pipelines

• Leverage AI tooling (e.g. Claude, Cursor, Copilot) to accelerate development and raise the quality bar for the whole team

• Develop and manage well-functioning databases and application layers

• Work closely with product, design, and data teams to deliver high-quality features end to end

• Participate in code reviews, architectural decisions, and knowledge sharing across the team

• Contribute to greenfield projects and help establish patterns and standards for a growing engineering org Requirements

• Proven experience as a full stack engineer with strong TypeScript across both frontend and backend

• Deep knowledge of Node.js and modern frameworks (e.g. Express, Fastify, NestJS)

• Experience with React.js and/or React Native for building product interfaces

• Hands-on experience with cloud platforms (GCP and/or AWS), with a strong preference for candidates who have managed infrastructure via IaC (Terraform)

• Solid understanding of security best practices, including authentication and authorisation patterns, secrets management, least-privilege IAM, vulnerability scanning, and secure CI/CD pipelines

• Strong knowledge of both SQL and NoSQL databases (e.g. PostgreSQL, MySQL, MongoDB)

• Experience with CI/CD pipelines, automated testing, and agile delivery practices

• Practical experience building with or integrating AI/LLM APIs (e.g. OpenAI, Anthropic, Vertex AI) and familiarity with AI-assisted development workflows

• Excellent communication skills and a collaborative, low-ego working style

• Additional backend language exposure (e.g. Python, Go, Java) is a plus

Benefits:

• Competitive salary & equity package.

• Enjoy 25 days of holiday per year (plus all bank holidays).

• Private Health Insurance.

• Extended sick pay and maternity/paternity leave pay.

• Cycle to work scheme.

• Flexible/hybrid working arrangement