Senior Software Engineer, Growth Monetization Web

Block is one company built from many blocks, all united by the same purpose of economic empowerment. The blocks that form our foundational teams — People, Finance, Counsel, Hardware, Information Security, Platform Infrastructure Engineering, and more — provide support and guidance at the corporate level. They work across business groups and around the globe, spanning time zones and disciplines to develop inclusive People policies, forecast finances, give legal counsel, safeguard systems, nurture new initiatives, and more. Every challenge creates possibilities, and we need different perspectives to see them all. Bring yours to Block.

The Role

We are on a mission to make commerce easy and accessible for businesses of all sizes. The Monetization team plays a critical role in this mission by increasing the adoption and utilization of Square’s products. Whether it’s through smarter pricing experiences, plan comparisons, or in-app upgrade paths, our work helps Sellers grow and enables success in driving business outcomes. 

We’re looking for a Senior Frontend Engineer to help us scale our platform, deliver high-impact features, and mentor other engineers. You’ll contribute to and evolve the technical vision for the Monetization Web platform, defining best practices and collaborating with adjacent Growth squads. This role blends team leadership with hands-on execution to shape the systems and experiences that power millions of seller interactions.

You Will

• Design and implement user-facing features and web experiences at scale.
• Build and maintain performant, accessible, and reliable web applications.
• Own the full feature lifecycle, from requirements gathering through implementation, testing, deployment, and monitoring.
• Contribute to shared component libraries and frameworks that accelerate development across Growth teams.
• Collaborate with backend, mobile, and design teams to prototype and iterate on new seller experiences.
• Lead team-level architecture improvements, championing performance, maintainability, and accessibility best practices.
• Design and build scalable product infrastructure and platform capabilities that support both our team and broader engineering teams, with a focus on solving problems at the platform level beyond individual user-facing features.
• Mentor and coach mid-level and junior engineers through code reviews and pair-programming.
• Foster a culture of technical excellence, inclusion, and high-velocity execution.
• Explore and apply emerging technologies, including AI-assisted tooling to improve engineering workflows and seller experience. 

You Have

• 8+ years of professional experience with JavaScript/TypeScript and modern web frameworks (React, Next.js).
• Hands-on experience building and operating large-scale web applications and reusable components. 
• Proven ability to lead large projects with strong collaboration, communication, and ownership.
• Deep expertise in performance tuning, accessibility compliance, reliability improvements. 
• Proven track record of owning production services and driving operational excellence and observability (monitoring, SLOs, incident response, metrics).
• Strong component-driven development skills and familiarity with design-system tooling).
• Excellent communication and collaboration skills, with experience working on cross-functional teams in a fast-paced environment.
• Familiarity with cloud infrastructure (AWS, Kubernetes) and CI/CD pipelines for frontend deployments.
• Curiosity about emerging technologies and a practical mindset for applying them in system design and workflow improvements.

Even Better

• Familiarity with A/B testing and experimentation tooling.
• Experience evolving shared UI library, platform-wide components or frameworks.
• Understanding of business and growth metrics, with the ability to translate them into UX and engineering strategies.
• Familiarity with GraphQL, Redux (or similar state management libraries), and component systems.
• Previous work in SaaS, subscriptions, or pricing applications would be a plus

Technologies We Use and Teach

• Languages: TypeScript/JavaScript (Primary), Java
• Frameworks & Core Technologies: Next.js, React, Ember, Node.js
• APIs & Communication: gRPC, REST, Protocol Buffers, GraphQL
• Experimentation: Optimizely, LaunchDarkly
• Testing: Jest, Playwright
• Tools: Remix, React Router, Vite, React Query, Snowflake, Sentry, Storybook, Datadog

We're working to build a more inclusive economy where our customers have equal access to opportunity, and we strive to live by these same values in building our workplace. Block is an equal opportunity employer evaluating all employees and job applicants without regard to identity or any legally protected class. We will consider qualified applicants with arrest or conviction records for employment in accordance with state and local laws and "fair chance" ordinances. We believe in being fair, and are committed to an inclusive interview experience, including providing reasonable accommodations to disabled applicants throughout the recruitment process. We encourage applicants to share any needed accommodations with their recruiter, who will treat these requests as confidentially as possible. Want to learn more about what we're doing to build a workplace that is fair and square? Check out our I+D page.