Kotlin Full-Stack Developer

Senior Full-Stack Engineer (Kotlin / Spring) – Onsights

About the Role

Onsights is an AI startup bringing advanced e-commerce analytics to brick-and-mortar retail.

We’re looking for a remote, full-time B2B Full-Stack Engineer with strong backend skills and B2-level English.

You’ll help design, build, and scale our core systems, working closely with backend, frontend,

and data science teams on high-performance data collection and analytics platforms.

What You’ll Work On

• Build and maintain backend APIs in Kotlin using Spring Framework

• Develop scalable services for data ingestion and processing

• Work with SQL/NoSQL databases (focus on performance and reliability)

• Integrate with internal and external systems

• Ensure platform security, stability, and scalability

• Participate in code reviews and mentor junior engineers

  
  

Tech Focus

• 70% Backend: Kotlin, Spring, Java

• 20% Databases: SQL/NoSQL, optimization, performance

• <10% Frontend: React

• Plus: TypeScript, Python, AWS (EC2, S3, SQS, EventBridge)

  
  

What We’re Looking For

• Master’s in Engineering or related field 8+ years full-stack experience,

• Expertise in media streaming technologies, services, protocols, and formats

• Experience with Spring, .NET, and frontend development with React

• Proficiency in Java/Kotlin, TypeScript, SQL, Python

• Hands-on experience with AWS (EC2, S3, SQS, EventBridge)

• English at B2 level