Overview
Staff Frontend Engineer, Activation and Engagement Web (Growth) role at Block. The Activation and Engagement Web team is a critical part of Square's Growth Product organization, with a mission to help sellers start, run, and grow their businesses with Square. As a Staff/Principal Frontend Engineer (L7), you’ll serve as the technical authority for our team while remaining deeply hands-on. You’ll drive cross-org architectural initiatives, set technical direction, implement key features, and mentor engineering talent across teams. This role blends strategic leadership with hands-on execution to shape the systems and experiences that power millions of seller interactions.
Responsibilities
- Design and implement complex, user-facing features and frontend architectures that scale.
- Build and maintain Next.js and React applications with high standards for performance, maintainability, accessibility, and reliability.
- Lead org-wide engineering initiatives impacting seller acquisition, activation, and adoption.
- Define and drive the technical vision for the Activation Web platform, setting architectural direction and best practices across Growth orgs.
- Champion frontend reliability and operational excellence, including monitoring, testing, and incident response standards.
- Lead root-cause analysis and resolution of high-severity incidents, driving cross-team improvements.
- Drive the deprecation of legacy frameworks like Ember and modernize our stack.
- Prioritize tooling and platform investments that improve developer velocity and extensibility.
- Collaborate with product, design, mobile, and backend teams to rapidly prototype and iterate on high-impact features.
- Mentor engineers across the org, fostering technical excellence and inclusive, high-velocity execution.
- Explore emerging technologies—including AI-assisted tooling—to improve engineering workflows and seller experience.
- Identify risks, opportunities, and architectural tradeoffs to influence strategic product and technical direction.
Qualifications
- 12+ years of experience with JavaScript/TypeScript and modern web frameworks (React, Next.js), delivering large features end-to-end (1+ year projects).
- Hands-on experience with large-scale web applications and sizeable contributor bases.
- Expertise with reusable components and scalable design systems.
- Proven track record delivering high-quality, performant production UIs.
- Strong leadership, collaboration, communication, and ownership in large projects.
- Deep experience in frontend reliability and system health, including leading SEV responses and reliability standards.
- Ability to define technical north stars and promote engineering quality and inclusive collaboration.
- Curiosity about emerging technologies and practical mindset for applying them to system design.
Even Better
- Experience leading frontend architecture for platform-wide components or frameworks.
- Knowledge of A/B testing frameworks and experimentation platforms at scale.
- Understanding of business and growth metrics and their relation to engineering and UX strategy.
- Commitment to web accessibility and real-world accessibility implementations.
- Familiarity with component systems like Storybook.
- History of leading org-level technical migrations or architectural transformations.
- Background in high-scale consumer or B2B SaaS products focused on acquisition and activation.
Technologies We Use and Teach
- Languages: TypeScript/JavaScript (Primary), Java
- Frameworks & Core Technologies: Next.js, React, Ember, Svelte, Node.js
- APIs & Communication: gRPC, REST, Protocol Buffers, GraphQL
- Experimentation: Optimizely, LaunchDarkly
- Testing: Jest, Playwright
- Tools: Remix, React Router, Vite, React Query, Snowflake, Sentry, Datadog
Block is an equal opportunity employer. We evaluate all applicants without regard to identity or any legally protected class. We will consider qualified applicants with arrest or conviction records in accordance with state and local laws. We are committed to an inclusive interview process and provide reasonable accommodations upon request. For more information, see our Privacy Policy and I+D page.
Salary information and location details are provided in the posting and may vary by location. Zone designations and pay ranges are listed for transparency and may be updated over time.
Seniority level
Mid-Senior level
Employment type
Full-time
Job function
Engineering and Information Technology
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