Sr. Software Engineer (Frontend) - Extensions Team

Role Overview

Senior Software Engineer on the Extensions Team at Cerby, owning and scaling Cerby’s cross-browser browser extension (Manifest V3) across Chrome, Edge, Firefox, and Safari. You’ll be responsible for the extension end-to-end—including the user-facing surfaces where credentials are managed, autofilled, injected, and authenticated via passkeys and federated identity providers.

Impact

• Deliver and improve a security-first product experience for users’ most sensitive credential interactions.
• Own quality, performance, and security of the extension end-to-end.
• Help lead a culture of responsible AI-assisted engineering and security-aware adoption.

Responsibilities

• Design & Develop: Build scalable, high-performance frontend extension functionality using AI-assisted tools and techniques.
• Security & Hardening:
  • Proactively identify vulnerabilities and implement robust solutions.
  • Treat the frontend dependency ecosystem as a security surface: manage PNPM workspace governance, audit packages for CVE exposure, enforce patching SLAs, and mitigate supply-chain risk across transitive dependencies.
  • Evaluate the security implications of adopting AI tools to ensure they don’t introduce new risk vectors.
• Collaboration: Partner with Product Managers, Engineering Managers, UX designers, and engineers to ship high-quality features.
• Code Excellence: Write clean, maintainable, efficient code; adhere to engineering best practices.
• Continuous Improvement: Participate in code reviews, share knowledge, and improve development processes.
• Innovation: Champion new frameworks/approaches to evolve the product while increasing personal and team efficiency through AI.

Requirements

• Senior-level ability to own extension quality, performance, and security end-to-end.
• Strong engineering practices: writing clean, maintainable code and collaborating effectively across functions.
• A security-first mindset, especially around vulnerability detection and secure dependency management.
• Experience applying critical evaluation to how tools (including AI) affect security.
• Experience collaborating in a remote-first environment.

Nice-to-Haves

• Deep familiarity with browser extensions (Manifest V3) and service-worker/background synchronization patterns.
• Experience managing supply-chain risk and enforcing dependency patching standards.