Full Stack Developer

Devonshire Hayes Recruitment; Greater London; On-site; GBP 70,000 - 100,000; Full time

Job summary

Devonshire Hayes Recruitment is helping a client build a multi-brand platform guiding users through the complete online journey, with identity verification and e-signature steps. You will ship customer-facing journey steps, REST APIs, and data migrations, while integrating third-party services behind clean interfaces.

You will work across React frontend and Node.js backend, design SQL Server schemas, write tests, and ensure robust input validation and audit trails for a regulated product.

Qualifications

• Strong React fundamentals and modern ES module tooling.
• Experience building REST APIs in Node.js with Fastify or Express.
• Strong SQL knowledge including schema design and transactions.
• Genuine testing habit to prevent defects and enable reliable delivery.
• Clear written communication and documentation of decisions and trade-offs.

Responsibilities

• Build and maintain customer-journey screens and shared components in React using a single codebase across branded sites.
• Develop back-end features in Node.js including a Fastify API and Express backend-for-frontend; durable background jobs with a SQL-backed outbox queue.
• Design and evolve SQL Server schema with forward-only migrations and transactional logic.
• Integrate and mock third-party services (identity-verification, lead-management) behind well-defined interfaces.
• Write meaningful tests across layers: Vitest, Testing Library, and Playwright end-to-end journeys against Dockerized DB.
• Build with regulated consumer product mindset: input validation, PII handling, audit trails, idempotent retries, graceful degradation.
• Collaborate to document technical decisions and improve the platform as it grows.

Skills

React

REST APIs

SQL

Testing

Documentation

Tools

Fastify

Express

SQL Server

Docker

Vitest

Testing Library

Playwright

Job description

The client is building a platform that guides consumers through the complete online customer journey, from their first visit through identity verification, e-signature and submission.

This is a hands-on product engineering role where you'll ship customer-facing journey steps, build and consume REST APIs, write database migrations and integrate third-party services behind clean, maintainable interfaces.

What you'll do

• Build and maintain customer-journey screens and shared components in React 19, using React Router 7, Vite and Sass/SCSS across multiple branded sites from a single codebase.
• Develop back-end features in Node.js, including a Fastify API, an Express backend-for-frontend and durable background jobs processed through a SQL-backed outbox queue.
• Design and evolve the SQL Server schema through forward-only migrations, using parameterised queries and transactional business logic.
• Integrate and mock third-party services, including identity-verification and lead-management providers, while keeping transport details behind well-defined interfaces.
• Write meaningful tests at every layer: Vitest unit and route tests, Testing Library component tests, and Playwright end-to-end journeys against a real database running in Docker.
• Build with the needs of a regulated consumer product in mind, including robust input validation, careful PII handling, audit trails, idempotent retries and graceful degradation.
• Work collaboratively to document technical decisions, follow established conventions and improve the platform as it grows.

What you'll bring

• Strong React fundamentals, including hooks, controlled forms, routing and state management, together with confidence using modern ESM tooling.
• Experience building and consuming REST APIs in Node.js using Fastify, Express or a comparable framework.
• Practical SQL knowledge covering schema design, joins, transactions and indexes. SQL Server experience is helpful but not essential.
• A genuine testing habit: you write useful tests because they prevent defects and support confident delivery, not simply because the CI pipeline requires them.
• Clear written communication and the ability to document decisions, explain trade-offs and work within established conventions.

Nice to have

• Experience working on multi-tenant or multi-brand products.
• Familiarity with queue or outbox patterns, Redis, PM2, nginx or Cloudflare.
• Exposure to regulated industries such as financial services or insurance, or experience with KYC and identity-verification journeys.