Senior Fullstack Engineer, Cross-platform
Welltech · Remote · Bulgaria · Lithuania · Armenia · Romania · Estonia · Latvia · Hungary ·
COMPENSATION
€•• – ••k
Listed on the employer's job board (Ashby)
- Senior Fullstack Engineer
- React Native + TypeScript
- Fully remote position
- AI-first development
- Cross-platform focus
Welltech is seeking a Senior Fullstack Engineer to own the cross-platform foundation for its global wellness applications, including Muscle Booster and Yoga-Go. You will work end-to-end across mobile, web, BFF, and infrastructure layers, leveraging AI-agentic workflows to drive product outcomes.
This role emphasizes ownership and rapid iteration, requiring close collaboration with product, design, and data teams. You will design scalable systems, improve developer productivity through shared tooling, and ensure reliable integrations for millions of users worldwide.
What you'll do
- Evolving cross-platform ecosystem for mobile, web, BFF, and infrastructure
- Designing scalable foundations for health and fitness applications
- Translating business needs into technical solutions with stakeholders
- Improving AI-agentic workflows to boost team productivity and quality
- Developing shared platform capabilities, internal tooling, and CI/CD pipelines
- Implementing native mobile integrations and advanced media experiences
- Building modular architectures and backend-driven UI solutions
- Ensuring reliable integrations between frontend clients and platform infrastructure
What you'll need
- Strong commercial experience with React Native and TypeScript
- Solid understanding of full-stack architecture including cloud layers
- Experience building scalable cross-platform systems and shared foundations
- Deep knowledge of software architecture, scalability, and performance
- Proficiency with CI/CD pipelines, automation, and modern workflows
- Comfortable working in AI-assisted or agentic development environments
- Experience with backend-driven UI architectures
- Focus on maintainability, reliability, testability, and fast iteration
Nice to have
- Experience building white-label mobile apps or multi-brand ecosystems
- Designing and implementing Backend for Frontend (BFF) services
- Hands-on backend development with TypeScript and Node.js
- Building internal developer platforms or shared tooling
- Familiarity with OWASP mobile security best practices
- Experience with Trunk Based Development, TDD, BDD, or XP
- Strong experience with native mobile integrations and video playback
- Hands-on experience with HLS streaming and native video players
Stack
- React Native
- TypeScript
- Node.js
- HLS
- AVPlayer
- ExoPlayer
How you'll work
- Fully remote position
- Global team with hubs in Europe and UK
Hiring process
- Recruiter call
- Meeting with Hiring Manager
- Skills assessment
- Live coding session