Senior Frontend Engineer

This role is suitable for a Middle-to-Senior Frontend Engineer with 2–4 years of experience who is proficient in TypeScript, modern JavaScript, React, TanStack Start or similar frameworks, Zustand, and TanStack Query.

The candidate should be familiar with designing frontend architecture, building complex production applications, optimizing performance, managing data-rich interfaces, and developing Playwright end-to-end tests.

They should also be comfortable owning features independently, collaborating across Product, Design, and Backend teams, and ideally have experience with web3, blockchain, dApps, AI-assisted development tools, or startup environments.

1. How would you structure a complex React application built with TypeScript and TanStack Start?

I would organize the application by domain or feature, separating UI components, business logic, data access, and shared utilities. TanStack Start routing and server capabilities would be combined with strongly typed interfaces, clear boundaries, and reusable patterns to keep the codebase scalable.

2. How would you use TanStack Query and Zustand together in a wallet or dApp application?

I would use TanStack Query for server state such as balances, transaction history, and blockchain responses, including caching and refetching. Zustand would manage local client state such as wallet connection status, active network, transaction flow state, and UI preferences.

3. How would you design a reliable account abstraction user flow?

I would model the flow as explicit states, such as preparation, signing, submission, confirmation, failure, and retry. The UI should provide clear feedback, handle rejected signatures and network errors, prevent duplicate submissions, and reconcile optimistic state with confirmed blockchain data.

4. What frontend performance techniques would you apply to a data-rich dApp?

I would use route-level code splitting, memoization where profiling justifies it, virtualization for large lists, efficient query caching, and debounced or paginated requests. I would also minimize unnecessary wallet and RPC calls and measure results using browser performance tools and real-user metrics.

5. How would you handle blockchain transaction lifecycle management on the frontend?

I would represent the transaction lifecycle explicitly and persist enough information to recover after refreshes or temporary network failures. After submission, the application should poll or subscribe for confirmation, handle replacement or failed transactions, and invalidate related TanStack Query data once the state changes.

6. How would you ensure type safety across frontend API and blockchain integrations?

I would define shared or generated types for API contracts and validate untrusted runtime data at boundaries. For blockchain interactions, I would strongly type contract arguments, transaction responses, chain identifiers, and error handling while avoiding unsafe casts unless they are isolated and justified.

7. How would you test a wallet connection and transaction flow with Playwright?

I would test the complete user journey using mocked wallet providers, RPC responses, and deterministic account data. Tests should cover successful connection, network switching, rejected signatures, failed transactions, loading states, retries, and accessibility-critical interactions.

8. How would you prevent race conditions when users switch accounts or networks quickly?

I would scope queries and local state by account and chain identifiers, cancel or ignore stale requests, and ensure responses are applied only if they match the current context. Query keys should include all relevant parameters so cached data cannot be shown for the wrong wallet or network.

9. What accessibility practices are important for wallet and dApp interfaces?

I would use semantic HTML, keyboard-accessible controls, visible focus states, appropriate labels, and meaningful status announcements for asynchronous transaction updates. Error messages should be clear and associated with the relevant controls, while loading and disabled states must remain understandable to assistive technologies.

10. How would you use AI-assisted coding tools responsibly in a production frontend project?

I would use them to accelerate scaffolding, refactoring, test generation, and exploration, but I would review every output for correctness, security, performance, and consistency with the architecture. Generated code would still require type checking, linting, tests, code review, and special scrutiny around wallet operations and user funds.

Join a fast-growing web3 company building self-custodial wallet experiences, account abstraction flows, and next-generation web and mobile dApps. As a Senior Frontend Engineer, you’ll own complex product workstreams, shape frontend architecture, and collaborate with Product, Design, and Backend teams using TypeScript, React, TanStack Start, Zustand, TanStack Query, and Playwright. This is a fully remote, full-time role open to candidates in Japan and Singapore, with East Asia preferred; salary details are not disclosed. It’s a compelling opportunity to work on high-impact blockchain products, influence technical direction, and grow within an ambitious startup environment.