Senior Frontend Engineer

Role Description

JTX is our trading app, and it runs on the fastest market infrastructure on Solana, which we also built. What nobody has done yet is make that speed something a trader can feel. That is this job.

JTX is live. Two frontend engineers built it to this point and you would be the third. The work now is one to a hundred:

• Harden what exists
• Make it hold up under real volume
• Expand onto mobile
• Raise the ceiling on every screen a trader touches

We're a small team with product-market fit. That means:

• High ownership: every team member drives significant technical decisions and shapes our product roadmap.
• Fast execution: we ship rapidly and iterate based on real-world feedback. Progress, not motion.
• High quality bar: the details are the product. We don't trade them for speed.

You'll own the surface of JTX across web and mobile: order entry, market data, charts, positions, execution quality, onboarding, and the wallet flows underneath all of it.

The role suits a generalist with strong taste. You'll partner with design, product, and the infrastructure team, and you'll make architectural calls that stick for years. If you've spent time thinking about how markets actually work on Solana and want to build the product layer on top of that, this is the role.

Stack: React 19 + TypeScript on Next.js. Jotai + TanStack Query. Tailwind with a token-based design system. TradingView Advanced Charts on our own datafeed. Privy wallets. WebSockets to our engine. Web ships as a PWA; native mobile apps are in development.

What’s Hard Right Now

• Data freshness: several live WebSocket streams (order book, trades, candles, stats) feed many panels at once; keeping them fast, consistent with each other, and honest through async gaps (stale quotes, pending fills)
• Performance: a data-dense terminal that stays smooth under constant streaming updates, including on mid-range hardware
• Security: wallet signing, session auth, strict CSP, hardened supply chain
• Shipping volume: three engineers own the entire surface of a live exchange; the backlog is bigger than the team, so throughput and prioritization are part of the job
• Keeping product behavior and design language consistent between web and mobile while being very attentive to nuances of each mobile platform
• Making execution quality something a trader can see in a glance instead of something they take on faith

What You'll Do

• Build and own the JTX client across web and mobile
• Ship real-time trading interfaces: order books, charts, order entry, positions, fill and execution visibility
• Hit tight latency and render budgets against streaming market data, and decide what belongs on the client versus the server
• Build wallet and signing flows, including self-custodial and embedded wallet onboarding
• Own the shared component, state, and data layers the rest of the product team builds on
• Make architectural decisions that hold as the codebase, the team, and the user base grow by an order of magnitude
• Ship fast, watch real users, iterate

Qualifications

• Attention to detail bordering on obsessive. You can look at a screen and say what is wrong with it, and it bothers you until it's fixed.
• 5+ years building production frontend, including something real-time, data dense, or financial
• Deep React and TypeScript. You can explain why a component re-rendered and then fix it.
• Mobile experience: React Native, Expo, or native iOS and Android
• Strong fundamentals: browser performance, memory, websockets, network behavior under load
• Security-first instincts around signing flows, key handling, and what should never touch a log
• Comfortable in a codebase that is already live. You can refactor and clean up without stopping shipping.
• Able to weigh business and engineering tradeoffs, and to explain complicated things simply

Relevant Background

• Trading terminals, exchange or brokerage frontends
• Consumer fintech apps at scale
• Charting, time series, or high-frequency data visualization (canvas, WebGL)
• Solana or EVM app development, wallet integrations, transaction signing
• Maintaining a public TypeScript library or design system

Salary

$175,000 - $195,000 a year