Frontend Developer at Topsort in Boston, MA

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 6 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. 

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

At Topsort, we communicate openly and move fast. We say things as they are, challenge each other early, and embrace feedback with curiosity—it’s how we build better, faster. Every experiment has a purpose, and every outcome helps us make the next decision smarter. There’s no single formula for success here; we find what works, improve it, and scale it.

We’re collaborative internally and competitive externally—never the other way around. The pace is quick, sometimes a 100-mph kind of fast, and that’s what keeps it exciting. We act with intent, lift each other up, and turn bold ideas into real results. No endless meetings here—if it can be done today, it gets done today.

About the Role:

We're looking for a Frontend Developer who takes pride in building interfaces that are fast, intuitive, and beautiful — and who wants to work on a product that's genuinely complex under the hood.

At Topsort, the frontend isn't just about rendering data. You'll be building dashboards that help advertisers manage campaigns, interfaces that let retailers configure their monetization stack, and real-time views of auction performance. The work is technically interesting, visually demanding, and directly tied to business outcomes.

You'll collaborate closely with designers, product managers, and backend engineers — and you'll be expected to own your work end-to-end, from architecture decisions to production.

What You'll Be Working On

• Build and own core product features — from the initial component design to deployment — across our advertiser dashboard, retailer console, and analytics surfaces.
• Translate complex auction and analytics data into clear, performant, and interactive UI experiences that make sense to non-technical users.
• Develop and maintain our front-end component library — building reusable, accessible, and well-documented components that the whole team benefits from.
• Collaborate with designers to implement pixel-perfect interfaces from Figma, pushing back constructively when something doesn't serve the user.
• Integrate with backend APIs and real-time data streams — working with our backend engineers to design clean data contracts and handle edge cases gracefully.
• Champion web performance — you'll own Core Web Vitals, lazy loading strategies, bundle optimization, and everything in between.
• Ensure accessibility and cross-browser compatibility across our entire product surface, so every user gets a consistent, reliable experience.
• Participate in architecture discussions — we want your opinion on the stack, not just your execution on tickets.
• Write tests and maintain quality — unit tests, integration tests, and a culture of shipping things that work.

What We Think You Need to Be Successful

We’re open to candidates who don’t check every box but show strong potential.

What We're Looking For

• Bachelor's in Computer Science, engineering or a related field from top schools
• 3+ years of experience in front-end development, ideally in a B2B SaaS or platform product.
• Deep expertise in React and modern JavaScript (ES2020+), with strong fundamentals in HTML and CSS.
• Experience with front-end build tooling — Webpack, Vite, Babel, NPM — and an understanding of what's happening under the hood.
• Strong instincts around responsive design, accessibility (WCAG), and web performance optimization.
• Comfort working with RESTful APIs and async data patterns.
• Experience with Git-based workflows and CI/CD pipelines.
• A portfolio or project examples that show you can take something from concept to production.
• Excellent communication skills — you can explain a technical tradeoff to a PM or a design decision to an engineer.

Nice to haves:

• Experience with Next.js or server-side rendering (SSR/ISR) — a real plus given our architecture direction.
• Familiarity with TypeScript and typed component systems.
• Experience building data-heavy dashboards or real-time UIs.
• Contributions to open-source projects or work on high-traffic web applications.
• Background in adtech, retail media, or marketplace platforms.