Senior Full-Stack Developer (TypeScript, NestJS, React) FinTech, High-load, Real-time

Balancify is looking for a Senior Full-Stack Engineer experienced with TypeScript, NestJS, and React, capable of working with high-load systems and large real-time data streams. You will play a key role in building our FinTech platform with complex business logic, intensive data flows, and strict performance requirements.

Tech stack

Backend: TypeScript, NestJS, MySQL/PostgreSQL, Docker, WebSockets
Frontend: React, CSR/SSR balancing concepts, Tailwind, WebSockets, State-management
Other: Architectural patterns, algorithms, database design & optimization, unit/integration/e2e testing

Requirements:

• 5+ years of experience with JavaScript/TypeScript
• Strong commercial experience with NestJS and large-scale enterprise systems
• 3+ years of production experience using React
• Deep understanding of JavaScript/TypeScript internals
• Experience working with high-load systems and real-time data
• Strong knowledge of architectural patterns and algorithms
• Experience designing scalable data models and SQL databases
• Ability to optimize complex SQL queries
• Proficiency with Docker, containers, and testing practices
• Strong analytical and problem-solving skills

Nice to have:

• Practical experience with Web3/Blockchain (even basic integrations)
• Experience integrating banking APIs or financial institutions
• Previous work on banking or payment platforms
• Knowledge of security principles, cryptography, and consensus algorithms
• English level: Intermediate+

What Balancify offers:

• Competitive compensation
• Flexible working schedule
• Social package (30 working days of annual leave)
• Challenging and engaging FinTech project with a diverse tech stack
• Opportunities for personal development and professional growth
• Work with talented, ambitious, and collaborative teams
• Educational opportunities: corporate courses, knowledge bases
• Compensation for professional certification and support for learning activities
• Corporate social responsibility initiatives

Responsibilities:

Backend

• Develop high-load backend services using NestJS
• Design scalable architecture, complex modules, and business flows
• Implement advanced FinTech algorithms
• Design relational database schemas and ensure scalability
• Optimize complex SQL queries and performance bottleneck
• Write unit, integration, and e2e tests
• Work with Docker and container-based environments
   

Frontend

• Build user-facing applications using React
• Ensure performance and responsiveness under high load
• Handle large real-time data streams using WebSockets
• Implement robust state management across the application
• Transform UI/UX designs into efficient, maintainable components
• Collaborate closely with backend engineers for smooth integration