Sr. Software Development Engineer (React/Typescript/Browser Extension Development)

Role

We are looking for a Senior Software Development Engineer to join our Frontend Engineering team and help build and evolve Zero Trust Browser, our Browser Detection and Response (BDR) extension that protects users directly inside Chrome, Firefox, and Safari.

This is more than standard UI work: you will build in-browser security capabilities detecting threats, enforcing enterprise policy, and analyzing content in real time across the extension's many feature modules and execution contexts. You'll turn product requirements and UI/UX designs into reliable, secure, and highly performant TypeScript that runs on millions of users' browsers without getting in their way.

This is a hands-on individual-contributor role for someone with strong engineering fundamentals who wants to grow their depth in browser-platform, security, and frontend engineering.

What You'll Do (Key Responsibilities)

• Build Extension Features: Translate product requirements and UI/UX designs into clean, well-tested, and performant browser-extension features, spanning from user-facing UI to deep in-browser security and detection capabilities
• Build Performant, Secure Tooling: Implement security-sensitive logic that runs on every page load with minimal overhead. You must care deeply about latency, memory consumption, and ensuring the browsing experience is never degraded
• Write Quality, Maintainable Code: Produce highly readable, modular code that follows established patterns and conventions, while actively participating in and elevating team code reviews
• Test & Debug Rigorously: Write comprehensive unit and integration tests for your work, and comfortably debug issues across complex browser contexts (background scripts, content scripts, popups, and extension pages) using browser developer tools
• Collaborate Cross-Functionally: Partner closely with UI/UX designers, backend engineers, and QA to ship features end-to-end, maintaining clear communication regarding progress and blockers

Who You Are (Success Profile)

• You Think at Scale: You connect your day-to-day work to the larger company mission and think globally. You build solutions, processes, and architectures that are not just effective today, but are built to last and support a high-growth organization
• You are Driven by Innovation: You possess a deep curiosity for how things work and are energized by solving complex technical hurdles. You believe in the power of technology to accelerate transformation and consistently hunt for more secure, scalable methods
• You are a Problem-Solver: You actively seek out engineering challenges because you are energized by finding solutions, knowing that solving the hardest problems delivers the biggest business and customer impact
• You are Data-Driven: You lean on data and analytics to uncover engineering truths, measure what matters, and guide informed architectural decisions replacing "I think" with "I know."
• You are a Learner: You have a true growth mindset and never stop developing your technical or leadership skills. You actively seek and implement feedback to become an exceptional collaborator and teammate

What We're Looking For (Minimum Qualifications)

• 2-4 years of professional software development experience, with meaningful time spent building production frontend applications in TypeScript and/or JavaScript
• Browser-extension development experience for Chrome, Firefox, and/or Safari. A solid working understanding of extension APIs, manifest versions (MV2 / MV3), permission models, and the separation between content scripts, background/service workers, and extension pages
• Strong command of core JavaScript (ES6+) and TypeScript types, async/await, closures, modules, and a precise mental model of how the language behaves
• Experience with at least one modern frontend framework or reactive UI library (e.g., React, Vue, Svelte); ability to pick up new frameworks quickly
• Proficiency with HTML5 and CSS3, including building responsive, component-based UIs
• Demonstrated curiosity and active exploration of AI tools, with a proven history of integrating new technologies to enhance daily workflows and augment problem-solving

What Will Make You Stand Out (Preferred Qualifications)

• Experience publishing extensions directly to a major browser store, or building extensions across multiple browser engines (Chromium, Gecko, WebKit) and successfully reconciling their API differences
• Familiarity with modern frontend build tooling (e.g., esbuild, Vite, Rollup, Webpack) and an active interest in customizing or optimization pipelines
• A basic understanding of web application security risks (XSS, CSRF, content isolation) and safe coding practices, combined with exposure to Node.js for tooling, scripting, or API integration

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