Senior Fullstack Mobile Engineer

United States Digital Space LLC; Greater London; On-site; GBP 90,000 - 130,000; Full time

Benefits offered by this job

Competitive Rates

Flexible working arrangements

Career development opportunities

Innovative projects

Collaborative culture

Job summary

United States Digital Space LLC in London is seeking a Senior Fullstack Mobile Engineer to own end-to-end delivery across backend and mobile features in a greenfield platform.

You will design scalable backend using NestJS, Node.js and TypeScript, and contribute to mobile features with React Native and Expo, while collaborating with Kotlin/Spring Boot teams to ensure robust API integration and secure, high-performance systems.

Qualifications

• Proven senior engineer capable of autonomous ownership of architecture, data modelling and deployment strategies.
• Strong track record delivering production-grade software in complex environments.
• Experience influencing architecture across team boundaries.

Responsibilities

• Design, build and maintain scalable backend services using NestJS, Node.js and TypeScript.
• Deliver end-to-end features across backend and mobile applications.
• Lead technical discussions and align with neighbouring teams across stacks.
• Design secure identity flows and enterprise authentication.

Skills

Senior engineering experience

Autonomous working

Architecture decisions

Tools

NestJS

Node.js

TypeScript

React Native

Expo

Kotlin

Spring Boot

PostgreSQL

Redis

Auth0

Docker

Docker Compose

AWS ECS

Job description

Senior Fullstack Mobile Engineer

We are looking for a Senior Fullstack Mobile Engineer with a strong emphasis on backend architecture to join the team developing a greenfield platform.

You will own the end-to-end technical delivery of features, with the majority of your time focused on designing and building a robust, secure, and scalable backend using NestJS, Node.js and TypeScript.

On the mobile side, you will contribute to feature integration and deployment within a React Native and Expo environment, ensuring seamless delivery across the full technology stack.

The platform operates within a large enterprise technology ecosystem, so this role requires a senior engineer who is comfortable driving technical discussions, making architectural decisions, aligning infrastructure, and collaborating with neighbouring teams working across different technology stacks, including Kotlin and Spring Boot.

This role requires onsite time in Pimlico and sits inside IR35.

Backend Architecture & Development

Design, build and maintain highly scalable, secure and testable backend services using NestJS, Node.js and TypeScript.

• Own backend architecture and technical decisions across the platform.
• Design robust APIs, services and integrations that support long-term scalability and maintainability.
• Apply appropriate software design patterns and engineering principles throughout the platform.

Mobile Development & Integration

Deliver end-to-end features across the backend and mobile application.

• Implement and optimise frontend capabilities using React Native and Expo.
• Work closely with backend and platform teams to ensure effective API integration and reliable mobile experiences.
• Support the build, release and deployment lifecycle of mobile applications.

Identity & Security

Own the integration of enterprise-grade authentication and authorisation workflows using Auth0.

• Design secure identity flows and ensure security best practices are applied across backend and mobile applications.
• Work with enterprise teams to align authentication and security architecture.

Data & Caching

Design efficient and maintainable relational data models using PostgreSQL.

• Optimise database queries and application performance.
• Implement high-performance caching and session-management strategies using Redis.
• Make informed decisions around data consistency, performance and scalability.

CI/CD & Infrastructure

Develop and maintain automated build, test and deployment pipelines.

• Manage CI/CD processes for backend services and mobile applications.
• Containerise applications using Docker and Docker Compose.
• Deploy and manage containerised services using AWS ECS.
• Collaborate with infrastructure and neighbouring engineering teams to ensure reliable and consistent environments.

Technical Leadership & Collaboration

Drive technical discussions and contribute to wider architectural decisions.

• Work collaboratively with teams operating across different technology stacks, including Kotlin / Spring Boot.
• Translate business and technical requirements into pragmatic, scalable solutions.
• Take ownership of technical delivery from design through to production.
• Provide technical leadership and promote engineering best practices across the team.

Requirements

Senior Engineering Experience

Proven experience working at Senior Engineer level, with the ability to operate autonomously and take ownership of architecture, data modelling and deployment strategies.

• Strong track record of delivering production-grade software in complex environments.
• Comfortable making technical decisions and influencing architecture across team boundaries.

Backend Expertise

Deep, production-proven experience with Node.js and TypeScript.

• Extensive hands-on experience with NestJS.
• Strong understanding of backend architecture, API design, scalability, security and performance.
• Strong understanding of software design patterns and architectural principles.

Database & Caching

Strong hands-on experience with PostgreSQL, including relational data modelling and query optimisation.

• Production experience with Redis, including caching, session management and data structures.

DevOps & Cloud

Strong experience with Docker and Docker Compose.

• Hands-on experience deploying and managing containerised applications using AWS ECS.
• Experience with automated CI/CD pipelines and deployment strategies.

Frontend & Mobile

Hands-on experience with React Native.

• Experience working with the Expo ecosystem.
• Comfortable delivering full-stack features spanning backend services and mobile applications.

Authentication & Security

Experience implementing complex authentication and authorisation workflows using Auth0.

• Strong understanding of application security and enterprise identity management.

Testing & Quality

Strong commitment to automated testing and engineering quality.

• Experience writing and maintaining unit, integration and E2E tests.
• Comfortable applying testing strategies across both backend and mobile applications.

Technology Stack

Backend: Node.js, TypeScript, NestJS

Mobile: React Native, Expo

Database: PostgreSQL

Caching: Redis

Authentication: Auth0

Cloud: AWS ECS

Infrastructure: Docker, Docker Compose

Testing: Unit, Integration & E2E

Enterprise Integration: Kotlin / Spring Boot

Benefits

• Competitive Rates
• Flexible working arrangements
• Opportunities for professional development and career advancement within a global company
• A dynamic, innovative, and supportive work environment, where your ideas and contributions are valued
• The chance to work on cutting-edge projects that are transforming the industry
• Most of all you get to work with a bunch of great people, where the whole team owns the project together in a politics-free environment. Our culture reflects our lean and self-organisation attitude. We encourage our colleagues to take risks, make decisions, work in a collaborative way and talk to everyone to enhance communication. Freedom and Responsibility go hand in hand, and we value commitment, feedback, and empathy.