[Hiring] Lead Full Stack Engineer @Weekday AI

Role Description

The Lead Full Stack Engineer will be responsible for the complete development lifecycle of our prediction market trading terminal—from the interactive real-time trading UI used by traders to the backend APIs that support market data, order routing, and portfolio management. As the first senior engineering hire, you will collaborate closely with the CTO to define the system architecture, deliver the initial product version, and expand the engineering team as we grow. This is not a conventional SaaS project. The terminal processes real-time WebSocket streams of live odds, updates the UI in under a second, executes on-chain trades via Polymarket’s CLOB, and incorporates AI-driven edge signals—all presented in a compact, Bloomberg-style trading interface. If you have experience building trading dashboards, real-time data platforms, or high-performance web applications and are eager to take a leadership role, this opportunity is for you.

• Lead the full stack development of the trading terminal, making decisions regarding architecture, technology stack, code quality, and release schedules.
• Develop the real-time trading UI with React/Next.js, including features such as the market discovery grid, analysis dashboards with live charts, order entry/betslip, position tracking, and an automated strategy builder.
• Design and build backend APIs (Node.js/Python) for aggregating market data, routing trade executions (Polymarket CLOB, Kalshi), tracking portfolio and P&L, and managing users.
• Implement WebSocket infrastructure to stream live odds, order book depth, in-play probability updates, and position mark-to-market data, ensuring sub-second latency from source to UI.
• Integrate with prediction market APIs (Polymarket Gamma API, CLOB/CTF Exchange, Kalshi) and sportsbook feeds to normalize market data and enable cross-platform trade execution.
• Build the on-chain transaction layer, including wallet integration, CLOB order signing, USDC settlements, and transaction status monitoring on Polygon.
• Create the frontend for the automation engine—a rule builder UI allowing traders to configure automated strategies with entry/exit triggers, Kelly-sized position management, and multi-leg hedging.
• Establish CI/CD pipelines, testing frameworks (unit, integration, end-to-end), monitoring and observability tools (Sentry, Datadog/Grafana), and deployment processes utilizing Docker and AWS/GCP.
• Take ownership of performance tuning, focusing on bundle size, rendering efficiency for data-heavy grids, WebSocket connection management, API response times, and caching mechanisms.
• Recruit and mentor junior and mid-level engineers as the team grows, implementing code review standards, maintaining engineering documentation, and facilitating technical onboarding.

Qualifications

• Over 6 years of full stack engineering experience, including at least 2 years in a lead or senior role responsible for end-to-end product delivery.
• Advanced proficiency in React (Next.js preferred), with expertise in managing complex state (Zustand/Redux), real-time data rendering, WebSocket integration, and optimizing performance for data-intensive UIs.
• Strong backend development skills in Node.js (Express/Fastify) or Python (FastAPI/Flask), with experience in RESTful API design, authentication (JWT/OAuth), rate limiting, and horizontal scaling.
• Hands-on experience with WebSockets or Server-Sent Events for real-time streaming applications such as trading platforms, dashboards, or live feeds.
• Skilled in using PostgreSQL, Redis, and message queues (Kafka/RabbitMQ/BullMQ) within event-driven architecture frameworks.
• Experience working with cloud infrastructure (AWS or GCP), containerization (Docker), CI/CD pipelines (GitHub Actions), and monitoring/observability systems.
• A strong sense of UI/UX design, capable of translating intricate data into clear, compact, and trader-friendly interfaces reminiscent of Bloomberg or TradingView, rather than generic dashboards.
• Familiarity with Git workflow practices, code review culture, and agile/sprint-based development methodologies.
• Excellent and structured English communication skills, with the ability to explain technical decisions to non-technical stakeholders.
• Preferred: Experience with Web3/blockchain integration (ethers.js, wallet connectors, on-chain transactions), crypto trading platforms, or fintech products.
• Preferred: Knowledge of charting libraries (TradingView Lightweight Charts, D3, Recharts) and large-scale data visualization.

Requirements

• React
• Next.js
• Node.js
• Python
• WebSockets
• PostgreSQL
• Redis
• Message Queues
• AWS
• Docker
• CI/CD
• Real-time Systems
• Fintech
• Crypto
• Web3
• Performance Optimization