Senior Frontend Engineer

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 is this Role 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. 
• Ensure cross-browser compatibility and responsive design for web applications.

What we expect from you:

• Bachelor’s in Computer Science, Design, or related field. 
• 5+ years of experience in front-end development. 
• Strong knowledge of JavaScript, HTML, CSS, and front-end frameworks such as React.
• Proficiency in modern JavaScript frameworks (React, Vue.js, or similar). 
• 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.
• Availability to work 4 days a week onsite from our Somerville office.

Desirable

• Demonstrated experience working in a three-tier application architecture
• Experience working with Python frameworks like FastAPI
• Experience working with PostgreSQL

About Topsort

At Topsort, we believe in the mission of democratizing the secret technologies of the walled gardens and creating a privacy-first cookie-free world of clean advertising with modern tech, friendly products, and AI. We believe in making advertising intuitive, intelligent, and genuinely cool, without any of the creepy ads or cookie-obsession (well, maybe just the chocolate ones). In a rapidly changing industry, we're on a mission to democratize monetization access for all and ensure that advertising doesn't leave any brand or seller feeling confused or overwhelmed

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 go