Principal Software Engineer (UI / React)

Job Title - Principal UI Engineer (Reactjs)

Job Location - Pune or Bengaluru

Experience - 8 to 10 years

Budget - INR 60 lacs

About the Position:

Our client is seeking a Principal UI Engineer to serve as the architect of our React ecosystem . In this role, you won't just build features; you will be the \"Engineer for the Engineers\" responsible for the scalability, performance, and developer velocity of our entire frontend organization.

Your mission is to ensure that our developers can ship world-class interfaces with high confidence and zero friction.

Key Responsibilities:

• React Architecture & Evolution: Own the transition and implementation of modern React patterns, including React Server Components (RSC), streaming SSR, and advanced data-fetching patterns (e.g., Next.js App Router or Remix).
• API Contract Simplification: Act as the primary bridge between UI and Backend/Platform teams. You will drive the design of \"Frontend-Friendly\" APIs, advocating for BFF (Backend-for-Frontend) patterns or GraphQL layers to aggregate complex microservices into simple, flattened contracts.
• Developer Experience (DX) Tooling: Architect and maintain a high-performance build pipeline. This includes migrating legacy Webpack/Babel setups to Rust-based tooling (Vite, Biome, or Turbopack) to achieve sub-second hot-reloading and lightning-fast CI builds.
• Design System Engineering: Lead the technical implementation of our headless UI component library. Ensure strict TypeScript safety, accessibility (Aria-compliance), and seamless integration with tokens-based design workflows.
• AI-Augmented Productivity: Evaluate and integrate AI coding assistants (e.g., Cursor, GitHub Copilot, or custom LLM agents) into the team’s workflow to automate boilerplate, unit test generation, and documentation.
• Performance Observability: Build custom dashboards to monitor Core Web Vitals and React-specific metrics (render counts, commit times). You are responsible for keeping our \"Time to Interactive\" (TTI) best-in-class.

Success Metrics for the First Year

• Build Performance: Reduce local development startup time and CI pipeline duration by >50%.
• Onboarding Velocity: Reduce the \"Time to First PR\" for new hires from days to hours through improved scaffolding and CLI tools.
• System Adoption: Achieve 90%+ adoption of the core Design System across all product squads.
• Code Health: Lower the Change Failure Rate by implementing automated \"guardrail\" tooling that catches architectural drifts before they hit production.

A great Principal UI Engineer doesn't just write code; they build a platform where writing great code is the path of least resistance.

How this differs from a Senior Role

Unlike a Senior React Dev, you aren't assigned to a product squad to build \"A dashboard\" You are horizontal. You are the one who decides how the dashboard page is built, which version of React we use, and how we measure its success.