Experienced Backend JavaScript Developer - Worldwide

This role is best suited for a Middle-to-Senior Backend JavaScript Developer with 3+ years of professional experience and strong expertise in Node.js and scalable backend systems. The candidate should understand system design, APIs, distributed architectures, network protocols (TCP/IP, HTTP, DNS, WebSockets, CORS), databases and messaging technologies such as MongoDB, Cassandra, RabbitMQ, Snowflake, and Kubernetes-based environments. They should be comfortable owning features end-to-end, working independently in an agile remote team, and building secure, high-performance, production-grade services.

1. How would you design a scalable backend system using Node.js and microservices?
   I would separate services by domain responsibility, define clear APIs or messaging contracts, and use asynchronous communication where appropriate to improve scalability and maintainability.

2. What is RabbitMQ, and when would you use it?
   RabbitMQ is a message broker used for asynchronous communication between services. It is useful for background jobs, event-driven systems, and decoupling services from direct dependencies.

3. How would you choose between MongoDB and Cassandra?
   MongoDB works well for flexible document-based storage and evolving schemas, while Cassandra is designed for massive scale, high availability, and distributed write-heavy workloads.

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

5. What is CORS and why is it important?
   CORS is a browser security mechanism that controls whether resources from one origin can access another origin. Proper configuration helps prevent unauthorized cross-origin requests.

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

7. How would you troubleshoot performance issues in a Node.js application?
   I would analyze logs and metrics, profile CPU and memory usage, identify blocking operations, optimize database queries, and investigate network bottlenecks.

8. What role does Kubernetes play in backend systems?
   Kubernetes automates deployment, scaling, load balancing, and management of containerized applications, improving reliability and operational efficiency.

9. How would you design an event-driven architecture for large-scale applications?
   I would use message queues or event brokers to decouple services, define event contracts clearly, and ensure proper retry, monitoring, and error-handling mechanisms.

10. What are the most important considerations in backend system design?
    Scalability, reliability, maintainability, security, observability, and performance are key factors when designing production systems.

Join a fully remote global team as an Experienced Backend JavaScript Developer, building scalable products with modern technologies including Node.js, MongoDB, Express, Kubernetes, RabbitMQ, Cassandra, and Snowflake. In this role, you’ll take ownership of features from design through production, contribute to system architecture decisions, and solve challenges around performance, scalability, and reliability in a fast-paced agile environment. You’ll work with cutting-edge backend infrastructure while collaborating with engineers who value autonomy, continuous learning, and high engineering standards. This is an excellent opportunity for developers who enjoy ownership, modern backend technologies, and the freedom to make a direct impact on products used at scale.