Senior Frontend Engineer

Topsort; City Of London; On-site; GBP 60,000 - 80,000; Full time

Job summary

A tech startup in the advertising sector is seeking a Senior Front-End Developer to build and optimize responsive user-facing features. The ideal candidate will have over 5 years of experience in front-end development, working closely with various teams. You will focus on JavaScript frameworks and ensure the highest standards of performance and accessibility. Join us to make a significant impact in a collaborative and fast-growing environment.

Qualifications

• 5+ years of experience in front-end development.
• Strong understanding of web performance optimization and accessibility.
• Preferred experience with server-side rendering and open-source contributions.

Responsibilities

• Develop, maintain, and optimize front-end components.
• Work closely with designers and backend developers to implement features.

Skills

Front-end development

JavaScript frameworks

Responsive design

Web performance optimization

Accessibility

Education

Bachelor’s in Computer Science, Design, or related field

Tools

Webpack

Babel

NPM

Next.js

FastAPI

PostgreSQL

Job description

Overview

We're quickly growing and super excited for you to join us!

Why Topsort? Why now?

Topsort is changing the way Retail Media works. By joining our scaling team, you'll feel your impact from day 1. The processes and messaging you build today will be a critical part of our foundation as we accelerate toward 200 Topsorters worldwide, and your innovations will leave a lasting mark on the industry, as a whole. Retail Media is on the verge of a new era, and Topsort is gathering the ecosystem together to shape a brighter future. Joining us now, you'll work directly alongside our co-founders and founding members to bring on Retail Media 3.0. If you're looking to define your career as something greater than yourself, come scale with us.

What it’s like to work at Topsort

Our team is all about straightforward communication, embracing feedback without taking it personally, and fostering a super collaborative environment. It’s a sports team that’s hyper focused on winning, collaborative internally, and competitive externally - never the other way around. We thrive on working in the open, lifting each other up, and getting things done with a sense of urgency. We\'re the kind of team that loves making bold choices, sharing extraordinary opinions, and maintaining a 100 mph pace. No endless meetings here – if it can be done today, we\'re all about getting it done today.

What this Role is like

As a Senior Front-End Developer at Topsort, you’ll be responsible for building and optimizing user-facing features that power our platform, working closely with designers, product managers, and backend engineers to deliver seamless and responsive web experiences. You’ll work primarily with modern JavaScript frameworks like React (and ideally Next.js), focusing on performance, accessibility, and scalability. This role is ideal for someone who thrives in a fast-paced startup environment, enjoys turning complex problems into intuitive interfaces, and takes pride in clean, maintainable code.

What you will do at Topsort

• Develop, maintain, and optimize front-end components and user interfaces.
• Work closely with designers, product managers, and backend developers to implement new features.

What we expect from you

• Bachelor’s in Computer Science, Design, or related field.
• 5+ years of experience in front-end development.
• Experience with front-end build tools and workflows (Webpack, Babel, NPM).
• Strong understanding of responsive design, accessibility, and web performance optimization.
• Preferred experience: Experience with Next.js or server-side rendering (SSR). Contributions to open-source projects or development of high-traffic web applications.
• Demonstrated experience working in a three-tier application architecture
• Experience working with Python frameworks like FastAPI
• Experience working with PostgreSQL

About Topsort

Today, Topsort has 5 major hubs worldwide, and employees in 13+ countries, including Menlo Park, Boston, Santiago Chile, Sao Paulo Brazil, Barcelona Spain, and Sydney Australia. We are a truly global company that was born in the pandemic that’s had rapid growth since out of a genius product, a customer-first mentality, and a hardworking team of talented individuals. Since our founding in 2021, we’ve gained customers in retail, marketplaces, and delivery apps in 40+ countries and quickly approaching the #1 position in the industry.

Do you enjoy a fast-paced environment? Do you like seeing your work create real-time impact, being part of a rocket ship from the very beginning? Let’s do the unimaginable - let’s make ads clean and cool again, with AI and modern technology.

Topsort Culture

• Speed:We work hard, set aggressive goals and execute flawlessly to accomplish them. We give candid feedback, push each other to set higher goals and produce more impact by always thinking “how do we do this faster and better”
• Fast Growth:We believe startup scaleup is just like a team sport. It\'s been written in our motto since day 1 that we are collaborative internally, competitive externally, and never the other round around. You are ultimately surrounded by just different people that are all here to help you get the job done and shine as a team.

Do you sound like the right fit? Let\'s dive right in!