Experienced Backend JavaScript Developer

This role is best suited for a Middle-to-Senior Backend JavaScript Developer with 3+ years of software engineering experience and at least 2 years focused on Node.js backend development. The candidate should have strong expertise in scalable backend architectures, system design, MongoDB, Express, Kubernetes, RabbitMQ, Cassandra, Snowflake, and network protocols such as HTTP, HTTPS, DNS, TCP/IP, CORS, and WebSockets. They should be comfortable owning features from design to production, working independently in a fast-paced agile environment, and collaborating effectively with a distributed engineering team.

1. How would you design a scalable backend architecture using Node.js, MongoDB, RabbitMQ, and Kubernetes?
   I would separate services by domain, use RabbitMQ for asynchronous communication, design stateless services for horizontal scaling, and leverage Kubernetes for deployment, orchestration, and resilience.

2. What are the differences between MongoDB and Cassandra, and when would you choose each?
   MongoDB is a flexible document database well-suited for evolving schemas and application development, while Cassandra excels at massive-scale distributed workloads with high write throughput and fault tolerance.

3. How would you design an event-driven system using RabbitMQ?
   I would define clear event contracts, use queues to decouple services, implement retry and dead-letter strategies, and ensure consumers are idempotent to handle duplicate message delivery safely.

4. Explain the differences between HTTP, HTTPS, and WebSockets.
   HTTP is a request-response protocol, HTTPS adds TLS encryption for secure communication, and WebSockets provide persistent bidirectional communication suitable for real-time applications.

5. What is CORS, and how does it work?
   CORS is a browser security mechanism that controls cross-origin requests. Servers specify which origins, methods, and headers are allowed through HTTP response headers.

6. How would you secure a Node.js backend application?
   I would implement authentication and authorization, validate all inputs, use HTTPS, manage secrets securely, apply rate limiting, log security events, and follow the principle of least privilege.

7. How would you troubleshoot performance problems in a Node.js application?
   I would analyze logs and metrics, profile CPU and memory usage, identify blocking operations, review database queries, and investigate network latency or external service dependencies.

8. What role does Kubernetes play in modern backend infrastructure?
   Kubernetes automates deployment, scaling, service discovery, load balancing, and recovery of containerized applications, improving reliability and operational efficiency.

9. How would you design a backend service to handle millions of requests reliably?
   I would focus on horizontal scalability, caching, efficient database access, load balancing, observability, fault tolerance, and asynchronous processing for non-critical workloads.

10. What are the most important considerations in backend system design?
    Scalability, reliability, security, maintainability, observability, performance, and the ability to evolve the architecture as business requirements grow are the key factors.

Join a globally distributed team as an Experienced Backend JavaScript Developer, building scalable, high-performance systems with Node.js, MongoDB, Express, Kubernetes, RabbitMQ, Cassandra, and Snowflake. In this fully remote role, you’ll own features from architecture and implementation through production deployment, contributing to critical system design decisions that impact performance, reliability, and scalability. You'll work in a fast-paced agile environment where autonomy, technical excellence, and continuous learning are highly valued, while collaborating with talented engineers across the stack. This is an excellent opportunity for backend developers who enjoy solving complex distributed-systems challenges, taking ownership of their work, and building modern software at scale.