Senior Full-Stack Engineer, AI‑Powered Web Platform

intercom; Greater London; Hybrid; GBP 104,000 - 142,000; Full time

Job summary

Fin, now part of Salesforce, seeks a Senior Full Stack Engineer to own the web platform across UI and backend services. You’ll collaborate with design, marketing, and product teams to deliver scalable web experiences and robust APIs.

You will optimize performance, contribute to infrastructure, and participate in A/B testing and analytics to drive data-informed decisions. This role requires deep expertise in JavaScript, React, Next.js, and CMS platforms, with a strong focus on delivery and

Qualifications

• 8+ years of experience in full stack development.
• Expert in front-end frameworks such as React, Next.js, Tailwind.
• Experience in CMS platforms Contentful and Sanity and marketing tools.
• Experience in CI/CD tools such as CircleCI to streamline development.
• Familiarity with infrastructure as code tools Terraform and cloud platforms like AWS, Vercel, CloudFront, S3.
• Experience with A/B testing and analytics to drive data-informed decisions.
• Knowledge of performance optimization for fast-loading websites.
• Experience in writing tests for front-end components (Jest/Mocha/Cypress).
• Bachelor’s degree in Computer Science, Software Engineering, or related field.

Responsibilities

• Design, build, and maintain end-to-end web solutions—from UI to backend services.
• Collaborate with design, brand, marketing, and content teams to deliver seamless experiences.
• Develop backend logic and APIs; manage data flows and third-party integrations.
• Optimize website performance with best practices and lazy loading.
• Set up and manage infrastructure with Vercel, AWS, CloudFront, Terraform, and CircleCI.
• Implement and maintain web analytics and support A/B testing for data-driven decisions.
• Stay current with emerging technologies to improve development processes and UX.
• Be comfortable writing backend software to unblock end-to-end development.
• Build using top tools; leverage AI-powered developer tools to solve meaningful problems.

Skills

8+ years experience

JavaScript

React

Next.js

Tailwind

CMS: Contentful

CMS: Sanity

CircleCI

Terraform

AWS

Vercel

CloudFront

S3

A/B testing

Jest

Mocha

Cypress

Bachelor’s degree

Education

Bachelor’s degree

Tools

CircleCI

Terraform

AWS

Vercel

CloudFront

S3

Job description

Fin, now part of Salesforce, seeks a Senior Full Stack Engineer to own the web platform across UI and backend services. You’ll collaborate with design, marketing, and product teams to deliver scalable web experiences and robust APIs.

You will optimize performance, contribute to infrastructure, and participate in A/B testing and analytics to drive data-informed decisions. This role requires deep expertise in JavaScript, React, Next.js, and CMS platforms, with a strong focus on delivery and