[Hiring] Senior Full Stack Engineer @Checkmate

Role Description

We’re looking for an experienced Senior Full Stack Engineer (Ruby on Rails, React.js) to join our team and help build and scale the systems that power our core applications. You’ll work closely with product managers, designers, and other engineers to design scalable backend systems, manage core data logic, and develop modern responsive user interfaces for a large, high-traffic platform that supports web and mobile experiences. This is a highly impactful role for someone who is passionate about performance, reliability, user experience, and writing clean, maintainable code.

What You’ll Do

• Frontend Development & UX Focus: Build and maintain modern web applications using React.js, ensuring responsiveness, scalability, and performance. Work closely with UI/UX designers to implement user-friendly interfaces, ensuring cross-browser compatibility and optimization.
• Backend Development & Core Services: Design, develop, and maintain critical backend services and core application logic using Ruby on Rails, ensuring high reliability, performance, and security.
• API Development: Design, build, and optimize RESTful or GraphQL APIs to provide efficient, reliable data access for the React frontend and other internal systems.
• Architecture & Performance: Architect and implement scalable full-stack systems. Continuously optimize performance, reliability, and efficiency through profiling, caching (e.g., Redis), and background job processing (e.g., Sidekiq).
• Database Management: Design, maintain, and optimize relational databases such as PostgreSQL and MySQL. Write and tune SQL queries for performance and scalability.
• System Reliability & Monitoring: Contribute to improving observability and performance monitoring. Quickly diagnose and resolve production issues across various environments and platforms.
• Code Quality & Automation: Write clean, efficient, and well-documented code emphasizing modularity and maintainability. Ensure code quality through best practices, comprehensive automated testing, and active participation in code reviews. Contribute to improving CI/CD pipelines, deployment workflows, and proactively identify areas for system and process improvement.
• Collaboration & Feature Delivery: Work closely with other engineers, product managers, and designers to deliver impactful, user-focused features that align with product goals.

Qualifications

• 5+ years of professional experience as a Full Stack Engineer, with a primary focus on Ruby on Rails and modern frontend development with React.js.
• Expert proficiency in React.js, JavaScript (ES6+), and TypeScript.
• Strong understanding of core React features including hooks, state management (e.g., Redux, Context API), and robust component design.
• Knowledge of responsive web design principles and mobile-first development.
• Strong knowledge of relational databases (PostgreSQL or MySQL), including schema design and query optimization.
• Strong understanding of modern JavaScript build tools and version control systems like Git.
• Proven experience with automated testing, testing frameworks, and CI/CD pipelines.
• Ability to profile, benchmark, and optimize applications for speed and scalability.
• Proven experience designing and implementing performant RESTful or GraphQL APIs.
• Demonstrated ability to diagnose and resolve complex production issues efficiently.
• Excellent communication and teamwork skills. Comfortable working cross-functionally with product, design, and other engineering teams.
• Must be available to collaborate in real time until at least 5 p.m. US Eastern Time.

Nice-to-Haves

• Experience with Next.js or other server-side rendering (SSR) frameworks.
• Familiarity with state management libraries beyond the essentials, such as Recoil or MobX.
• Strong understanding of web performance optimization techniques.
• Experience with major cloud platforms (AWS, GCP, Azure).
• Familiarity with containerization (Docker) and orchestration tools (Kubernetes).
• Understanding of UI/UX principles and experience working with design tools like Figma or Sketch.
• Familiarity with monitoring and observability tools such as Datadog, Scout, New Relic, or Bugsnag.
• Experience working in an Agile or Scrum development environment.