Senior Frontend Engineer

We’re hiring a Senior Frontend Engineer to help build a browser-based, real-time financial platform. This is not a typical dashboard role. The frontend will receive fast, continuous streams of data and present them through responsive charts, order-book views, positions, order-entry workflows, account state, and operational alerts. Small mistakes can create misleading information or unsafe user actions, so correctness matters as much as speed and visual polish. The product is at an early stage. The deployment foundation is in place, but many of the core product surfaces still need to be designed and built. You’ll have meaningful ownership over frontend architecture, engineering standards, and the way the product handles live data. What you’ll work on - Build production frontend features using React and Next.js. - Develop responsive views for live prices, charts, market depth, orders, positions, balances, and connection status. - Integrate REST APIs and authenticated WebSocket streams. - Handle snapshots, incremental updates, reconnects, duplicate events, sequence gaps, stale responses, and temporary disconnections. - Keep high-frequency updates from causing unnecessary React renders or freezing the browser. - Design clear loading, empty, stale, error, and recovery states. - Build safe order-entry flows with validation, confirmation, pending states, rejection details, and protection against accidental duplicate actions. - Translate product designs into precise, accessible, responsive interfaces. - Add automated tests for critical components and user flows. - Review pull requests and help establish maintainable frontend patterns. - Work closely with backend engineers on API contracts, event schemas, and end-to-end behavior. - Investigate production issues using logs, browser tooling, and reproducible test cases. What we’re looking for - Strong professional experience with React and modern JavaScript. - Production experience with Next.js. - Good TypeScript knowledge, including validation of data received from APIs and WebSockets. - Experience building complex, stateful web applications. - A solid understanding of component design, state ownership, data fetching, caching, and asynchronous behavior. - Experience consuming real-time data through WebSockets, server-sent events, or similar systems. - An ability to reason about out-of-order events, dropped messages, reconnect behavior, and stale state. - Strong HTML and CSS skills, including responsive layouts and accessibility. - Experience testing React applications with Jest and related testing tools. - Good performance instincts. You should know how to profile a slow interface and fix the actual bottleneck. - Clear written communication and the ability to work independently in a distributed team. Particularly relevant experience You’ll stand out if you have worked on one or more of the following: - Trading, brokerage, fintech, analytics, monitoring, gaming, or other real-time applications. - Financial charts, order books, data grids, or dense operational interfaces. - High-frequency UI updates without sending every event through global React state. - Update batching with `requestAnimationFrame` or a similar display-rate strategy. - Large lists or tables using virtualization. - Web Workers for CPU-heavy browser processing. - Client-side queues with explicit memory limits and backpressure behavior. - WebSocket recovery using snapshots before incremental updates resume. - Optimistic actions that reconcile safely with authoritative server state. - Frontend observability, performance measurement, and production incident investigation. - CI workflows, preview deployments, ESLint, Jest, and Vercel. Direct trading experience is useful, but it is not mandatory. Strong real-time application experience can be equally relevant. How we work - The backend remains the authority for orders, balances, positions, permissions, and execution status. - The frontend must communicate uncertainty honestly. Disconnected or stale data must never look live. - Critical flows require tests and clear recovery behavior. - Pull requests go through automated tests, linting, production builds, and review. - We prefer straightforward solutions that are easy to inspect and operate. - We expect engineers to raise edge cases early and explain tradeoffs clearly. - Product delivery includes implementation, verification, documentation, and follow-through after release. What success looks like During your first few months, you should be able to: - Establish frontend patterns that remain understandable as the product grows. - Deliver real-time product views that stay responsive under sustained update volume. - Build predictable reconnect and state-recovery behavior. - Make order-entry and account-state workflows safe and easy to understand. - Improve automated coverage of the highest-risk user journeys. - Give the team measured performance evidence instead of relying on subjective impressions.