Sr. Software Engineer (Frontend) - Extensions Team
Remote
Job Summary
Design and scale the Manifest V3 browser extension that manages application passwords, autofill, and credential injection across Chrome, Edge, Firefox, and Safari. Own the quality, performance, and security of the extension end-to-end, including PNPM workspace governance, CVE auditing, and supply-chain risk management for the frontend dependency ecosystem. Build high-performance UI surfaces with React and TypeScript while actively integrating AI-assisted tools to improve team efficiency and accelerate impact. Lead a security-first engineering culture by mentoring developers, conducting rigorous code reviews, and fostering an environment where experimenting with AI is encouraged. Collaborate with product managers, designers, and engineers to deliver features that protect users' most sensitive data, ensuring robust authentication flows and mitigating vulnerabilities like XSS and CSRF.
Required Qualifications
- 5+ years of professional software engineering experience, with a focus on building and scaling SaaS applications
- Prior experience developing and maintaining Distributed Applications
- Previous experience mentoring junior developers and conducting security-first code reviews
- Manifest V3 service-worker model: ephemeral execution and state persistence across termination (chrome.alarms, keep-alive), plus the distributed-system concerns that come with it — cross-tab coordination, background sync, and token-refresh/session races
- Content scripts and injection into untrusted pages: isolated-world vs MAIN-world execution, Shadow DOM isolation, and MutationObserver-based DOM resilience
- Message passing across content scripts, service worker, popup/side panel, and offscreen documents, with sender/origin validation as a security boundary
- Cross-browser delivery to Chrome, Edge, Firefox, and Safari: API divergence (chrome.* vs browser.*), MV2/MV3 differences, Safari packaging, and per-store review/release (staged rollout, rollback, remote-code ban)
- Native messaging with native host applications, plus extension-specific performance (service-worker cold-start, bundle size, content-script efficiency)
- Strong React + TypeScript with utility-first CSS (e.g., TailwindCSS), building UI across extension surfaces (popup, options, side panel, in-page) that is responsive, accessible (WCAG/ARIA), and reusable via a design system
- Core frontend and browser fundamentals: browser API, client-side storage (localStorage, IndexedDB, chrome.storage), networking (fetch/XHR), and performance optimization
- Designing, consuming, and optimizing REST APIs with efficient data-fetching and caching (e.g., TanStack Query)
- Front-end security: mitigating XSS, CSRF, and CORS, and applying CSP, including the extension's own CSP model
- Modern authentication and identity: OAuth 2.0 / OIDC, SAML, SCIM, and WebAuthn / FIDO2 / passkeys; prior IAM or security experience
- Testing (unit, integration, component) and observability (metrics, traces, logs; OpenTelemetry/Datadog a plus), owning delivery end-to-end from design to production in an Agile/CI-CD environment
Desired Qualifications
- Experience working with security compliance frameworks (SOC 2, GDPR, HIPPA, etc.)
- Familiarity with encryption processes and key management
- Prior experience in a venture funded high-growth SaaS startup preferred
- OpenTelemetry/Datadog
- Resourceful Achiever: Self-motivated, proactive, and adaptable in solving complex technical challenges
- Product Minded: Strong ability to understand customer value, to translate customer needs into software products that deliver tangible customer value
- Precision Executor: Focused on optimizing performance, scalability, and reliability in software delivery
- Team Player: Strong interpersonal skills, fostering a culture of collaboration and shared success. Actively mentor other engineers
- Lifelong Learner: A continuous curiosity to learn and explore emerging technologies and industry trends
- Innovative Thinker: Open to creative solutions, and comfortable navigating ambiguity
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