Senior Frontend Engineer - JTX

Accountabilities: Frontend development and ownership: Build, maintain, and scale the trading application across web and mobile, taking responsibility for the complete user-facing experience. Real-time trading interfaces: Develop and improve order books, charts, order entry, positions, market statistics, and execution visibility to help traders make informed decisions. Performance and latency optimization: Ensure responsive interfaces under continuous market-data updates by meeting strict rendering and latency requirements, optimizing browser performance, and managing client-side resources effectively. Real-time data architecture: Maintain consistency and freshness across WebSocket streams for order books, trades, candles, and market statistics, including handling asynchronous updates, stale quotes, and pending fills. Wallet and transaction flows: Build secure wallet onboarding, authentication, signing, and transaction experiences for both self-custodial and embedded wallets. Shared frontend architecture: Own and improve reusable components, state management, data layers, and design-system foundations that support consistent development across the product. Technical architecture and scalability: Make architectural decisions that support substantial growth in the codebase, engineering team, and user base while maintaining reliability and maintainability. Web and mobile consistency: Extend the product to mobile while maintaining consistent product behavior and visual design across platforms and respecting platform-specific user experience requirements. Security and reliability: Apply security-first practices to wallet signing, session authentication, Content Security Policy (CSP), sensitive data handling, and software supply-chain integrity. Continuous product improvement: Ship improvements frequently, observe real-world user behavior, collaborate with stakeholders on prioritization, and refine the product based on feedback and measurable outcomes. Requirements At least 5 years of professional experience building and maintaining production frontend applications, ideally involving real-time systems, data-intensive interfaces, or financial products. Deep expertise in React and TypeScript, including component architecture, state management, rendering behavior, and performance optimization. Experience building mobile applications using React Native, Expo, or native iOS and Android technologies. Strong understanding of browser performance, memory management, WebSockets, network behavior under load, and responsive interfaces with frequent data updates. Experience designing or maintaining complex frontend data flows where freshness, consistency, and accurate representation of asynchronous states are essential. A strong security mindset, particularly around wallet integrations, transaction signing, authentication, key handling, and protecting sensitive information from logs and unintended exposure. Ability to work confidently in an established, live codebase, improving architecture and refactoring existing systems without disrupting product delivery. Strong product judgment and attention to detail, with the ability to identify interface issues, improve usability, and maintain a high standard of visual and functional quality. Ability to balance business priorities with engineering trade-offs, communicate complex technical concepts clearly, and make sound decisions independently. Comfort working in a small, fast-moving engineering team where ownership, execution, prioritization, and accountability are essential. Experience in one or more of the following areas is advantageous: trading terminals, exchange or brokerage platforms, consumer fintech applications, charting and time-series visualization, canvas or WebGL rendering, Solana or EVM application development, wallet integrations, transaction signing, public TypeScript libraries, or design systems. Benefits Salary: $175,000–$195,000 per year. Work arrangement: Remote position based in the United States. High ownership: Opportunity to influence technical architecture, product direction, and the evolution of a live trading application. Technical challenges: Work with React, TypeScript, Next.js, real-time WebSocket data, advanced charting, wallet integrations, and Solana-based trading infrastructure. Product impact: Help make trading execution, market data, and complex financial interactions more transparent and intuitive for users. Small-team environment: Collaborate closely with engineering, product, design, and infrastructure teams with significant responsibility and direct influence on delivery. Growth opportunity: Contribute to scaling the frontend architecture and expanding product capabilities across web and mobile. Additional benefits: Healthcare, retirement plans, paid time off, bonuses, equity, and other employee perks were not specified in the provided job description and should be confirmed during the hiring process.