Senior ReactJS Engineer

Fliff is the arena for high-upside play. We are dismantling the paywalls of legacy sportsbooks and reimagining the economics of social games to pioneer the next generation of rewards-driven entertainment spanning sports, casino, predictions, collectibles, and beyond.

Powered by a frictionless freemium architecture, Fliff democratizes access and gives millions of players nationwide a real stake, real thrill, and real upside. By combining authentic competitive drive with instant rewards and interactive games, we are turning passive sports fans and casual gamers into active, empowered participants – unlocking the player in everyone.

Who We Are Looking For

If you are passionate about building scalable and engaging web applications, we want you on our team! Fliff is seeking a talented

Sr. ReactJS Engineer

to join our growing Social Sportsbook team. You’ll be part of a cross-functional group responsible for the full software development life cycle, focusing on delivering top-tier web experiences for both mobile and desktop platforms. The Sportsbook Reliability is a dynamic team that brings together skilled engineers and product managers who collaborate closely to build, release, and support live apps that our users love.

This role requires full working-hour alignment with Central European Time (CET ±2 hours) to enable daily, real-time collaboration with our Sofia-based team. We are considering candidates located within this time zone range. Applicants outside CET ±2 hours will not be considered.### The Role:

• Develop and maintain responsive web applications using ReactJS, ensuring a seamless experience across devices.
• Collaborate with backend, DevOps, and designers to implement new features and optimize the live product.
• Support the live platform by identifying and resolving real-time performance issues.
• Design scalable solutions with attention to responsive UIs using pure CSS/SCSS without relying on external frameworks.
• Mentor junior engineers and provide code reviews to maintain high standards.
• Leverage Redux, React-Redux bindings, and middleware (Thunk/Saga) for state management.
• Implement RESTful APIs using axios and fetch, with optional GraphQL integration via Apollo client.

Experience Required:

• 5+ years of experience building modern web applications, with strong expertise in ReactJS and React Hooks (useState, useEffect, custom hooks).
• Advanced TypeScript skills, including utility types (Partial, Pick), generics, and infer keyword usage.
• Solid understanding of Redux mechanics, React-Redux bindings, and internal hooks.
• Strong CSS/SCSS knowledge, with the ability to build reusable, responsive UIs without external libraries (e.g., Material UI, Tailwind).
• Knowledge of WebSockets (native and socket.io) to handle real-time data.
• Experience with RESTful APIs, axios, and fetch, with optional GraphQL and Apollo Client experience.
• Familiarity with React Router for dynamic imports, lazy loading, and code splitting.
• Comfortable with UI tools like Figma, along with React DevTools, Chrome debugger, and testing tools such as Jest and Cypress.
• Adaptability and problem-solving skills to handle real-time challenges and evolving project requirements.
• Strong communication skills and a collaborative mindset to work effectively with cross-functional teams.

Benefits

• Competitive compensation package.
• Opportunity for professional development in a dynamic, fast-growing company.
• Supportive, collaborative, and knowledge-driven work environment.
• Engaging and challenging role with the freedom to innovate and build exciting solutions in the sports gaming industry.

Why Join Us?

At Fliff, you’ll have the opportunity to shape the future of social sports betting by working on exciting, fast-paced projects and supporting a live app. We value creativity, collaboration, and problem-solving, and we’re looking for someone ready to take ownership and make an impact.
We are a multinational company with our headquarters based in Philadelphia, and offices in New York, Austin, and Sofia, Bulgaria. Wherever we are in the world, we pride ourselves on being a close-knit, focused team that is welcoming and friendly, and the work that we do is always interesting and rewarding. Wherever we are in the world, we pride ourselves on being a close-knit, focused team that is:

Welcoming and Friendly

We want to reflect the diversity of the cities we serve. By creating an inclusive culture where everyone can thrive, we’ll make Fliff better for employees and customers alike.

Lively and Creative

We respect and value each other’s ideas, experience and expertise. There is no such thing as a bad idea; ideas that are executed and ideas that are discarded after consideration.

Stimulating and Rewarding

We know bright minds love a challenge, and we understand your desire to see your hard work pay off. We’ll make sure your daily tasks align with your career ambitions as we grow together.

Equal Employment Opportunity Statement

Fliff is an equal-opportunity employer. We celebrate diversity and are committed to creating an inclusive environment for all employees. All qualified applicants will receive consideration for employment without regard to race, color, religion, gender, gender identity or expression, sexual orientation, national origin, genetics, disability, age, or veteran status.

Join Our Team!

If you're ready to be part of an exciting, innovative, and dynamic team, apply now to help shape the future of sports gaming with Fliff.

 

• IMPORTANT NOTICE: The privacy and security of applicant information is paramount and we take fraud attempts very seriously. Please note that Fliff will never ask for payment or personal financial information during the application process. All of our legitimate job opportunities can be found on our official career site (https://www.getfliff.com/careers https://www.getfliff.com/careers). Please be cautious of communications and links that come from non-company email addresses (@getfliff.com), social media messaging platforms or unsolicited phone calls.