Senior Web & Mobile Developer

Location: Poland only, fully remote

Job Type: B2B, full time

What’s the position?

We’re looking to engage a Senior Web & Mobile Engineer based in Poland on a B2B contract basis to support our growing technology function. This is an opportunity to help build and evolve customer-facing experiences across web and mobile, alongside internal Back Office applications used to operate and manage our casino platform.

The engagement requires strong React.js expertise and extensive React Native experience, with the ability to deliver across browser-based applications, native mobile platforms, and operational tooling.

You will collaborate closely with Product Management, Design, QA, Backend Engineering, Casino Operations, and other stakeholders to deliver secure, performant, and user-centric solutions. The scope includes customer-facing products and Back Office capabilities supporting day-to-day casino operations, configuration, content management, and operational workflows.

We’re seeking an experienced engineering professional who has delivered production-grade applications using both React.js and React Native, understands the full client development lifecycle, and can work confidently across web, cross-platform mobile, native platform requirements, and complex internal web applications.

Key Responsibilities:

• Work in an agile, cross-functional team to deliver the best possible platform experience across web, iOS and Android.
• Develop and maintain high-performance web applications in React.js and mobile applications in React Native using TypeScript.
• Break down features into requirements, contribute to estimation, refine user stories, and help define appropriate test coverage.
• Develop frontend and mobile code to a high standard and perform code reviews for other engineers.
• Collaborate with Backend Developers and Architects to design APIs and solve technical challenges across REST, GraphQL and WebSocket integrations.
• Support QA, Product and Release Management in moving development items safely to production.
• Build and maintain mobile capabilities such as push notifications, background processing/loading and offline/local content storage.
• Participate in continuous integration and delivery for web and for Apple App Store / Google Play Store releases.
• Use analytics, debugging and performance tooling to understand and continuously improve the end-user experience.
• Communicate effectively and proactively in English with Engineering Managers, Product Owners and other stakeholders.
• Work effectively in a highly regulated, high-traffic environment.

What are we looking for?

We are looking for an engineer who is willing to tackle problems with innovative ideas and high-quality technical implementations. You will not solely be focused on what we are building now but also understands where the product is going and how technical choices affect the customer experience across platforms.

You will have:

• 5+ years of professional frontend and/or mobile application development experience, with substantial recent production experience across both web and mobile.
• Strong React.js expertise and 3+ years of production experience developing React Native applications with TypeScript.
• Strong TypeScript and JavaScript knowledge, plus solid HTML and CSS experience.
• Extensive experience with state management in large applications using MobX, Redux or similar tools.
• Strong experience integrating REST, GraphQL and WebSocket APIs.
• Experience building secure, performant, user-centric applications at scale.
• Strong understanding of the client development lifecycle, including application structure, platform and device APIs, debugging, performance, security, testing and deployment.
• Strong knowledge of client-server architecture and proven ability to contribute to technical and application architecture decisions.
• Strong communication skills, both written and verbal.
• Bachelor’s degree in Computer Science or a related field, or equivalent practical experience.

Nice to have

• Experience in gaming, sportsbook, fintech or another high-traffic, regulated environment.
• Strong browser-based debugging and web performance testing experience.
• Familiarity with Webpack and modern frontend/mobile testing libraries.
• Experience with MobX in production.
• Exposure to backend or full-stack development and API design.
• Experience mentoring other engineers or taking technical ownership across web and mobile workstreams.