Lead Full-Stack Engineer (.Net and React) / Tech Lead

About the Role

As a Lead Full-Stack Developer (Tech Lead), you will take a hands-on leadership role in the design, development, and delivery of high-traffic, customer-facing applications across international markets including the United Kingdom, Germany, Spain, France, and Japan. In addition to building scalable solutions using React, .NET Core, .NET 6+, and C#, you will guide the technical direction of the team, mentor engineers, and ensure best practices in architecture, code quality, and deployment.

This is a high-impact role where you’ll shape how we scale and evolve our international platform, which supports 1M+ daily users and processes over 2B monthly requests. You’ll work cross-functionally with Product, UX, and Engineering stakeholders and help drive our strategy around performance, scalability, and AI integration.

What You’ll Do

• Lead the design and development of full-stack web applications using React and .NET technologies.
• Act as a technical mentor and thought leader for a team of engineers, supporting growth and encouraging a culture of engineering excellence.
• Collaborate with Product Managers, UX Designers, and cross-functional teams to translate business requirements into scalable technical solutions.
• Set and maintain high standards for code quality, testing, and CI/CD practices.
• Conduct code reviews, provide architectural guidance, and ensure alignment with best practices.
• Monitor production systems, ensure high availability and performance, and proactively address technical debt.
• Drive the implementation of AI-powered features and LLM-based flows, contributing to our innovation strategy.

• Promote a DevOps mindset and lead continuous improvements in deployment frequency, development velocity, and system reliability.

   

What We’re Looking For

• 7+ years of experience in commercial full-stack development, with at least 2+ years in a technical leadership or lead developer role.
• Deep expertise in .NET Core, C#, and React.
• Strong understanding of modern web architecture, microservices, REST APIs, and asynchronous programming.
• Proficiency with automated testing frameworks such as Jest/Vitest, Playwright, and NUnit.
• Experience guiding teams through Agile development processes and continuous integration/delivery.
• Upper-Intermediate level of English or higher, with strong communication and collaboration skills.
• A proactive, solution-oriented mindset with a passion for mentoring and enabling teams.

• Curiosity and enthusiasm for AI technologies, with a desire to explore and implement AI-driven solutions.

   

Perks and Benefits

• Time off throughout the year (paid and unpaid)
• Professional development support and encouragement
• Resources to help improve your overall well-being
• Free membership to dive into JA product