Ensuring performance and reliability are critical aspects when deploying applications in a production environment. Optimizing performance involves efficient resource utilization, minimizing response times, and handling high user loads effectively. Reliability entails robust error handling, graceful failure recovery, and implementing fault-tolerant measures to ensure uninterrupted operation. By prioritizing both performance and reliability, organizations can deliver a seamless user experience and maintain the stability of their deployed applications.

The focus of this article is on sharing best practices for optimizing performance and ensuring reliability when deploying Express applications in a production environment from dev ops perspective.

Production Environment Best Practices

Here are several measures you can take within your system environment to enhance your application’s performance:

  1. Set NODE_ENV to “production”
  2. Ensure your app automatically restarts
  3. Run your app in a cluster
  4. Cache request results
  5. Use a load balancer
  6. Use a reverse proxy

Set NODE_ENV to “production”

The NODE_ENV environment variable plays a crucial role in determining the runtime environment of an application, typically distinguishing between development and production. To enhance performance, one straightforward step is to set NODE_ENV to "production" specifically for an Express application.

When NODE_ENV is set to “production,” Express implements several optimizations, including:

  • View template caching: Express caches rendered view templates, eliminating the need for repetitive rendering operations. This improves the response time for subsequent requests, as the cached templates can be served quickly.

  • CSS file caching: Express caches CSS files generated from CSS extensions, such as Sass or Less. By serving cached CSS files, the application reduces the need for recompilation, resulting in faster response times and improved performance.

  • Less verbose error messages: In the production environment, Express generates less verbose error messages. This helps prevent sensitive information from being exposed to potential attackers, reducing the risk of security vulnerabilities.

Ensure your app automatically restarts

In a production environment, it is crucial to ensure that your application remains online without any significant downtime. This requires proactive measures to handle potential crashes, both at the application level and the server level. To account for these eventualities, consider the following approaches:

  • Process manager for application restart: Employ a process manager, such as PM2, to monitor and manage your application. The process manager will automatically restart the application (and Node.js) in the event of a crash. This helps maintain application availability and minimizes downtime.

  • **Utilize the OS init system for process manager restart: **Leverage the init system provided by your operating system to restart the process manager itself in case of an OS crash or reboot. The init system ensures that the process manager is automatically restarted upon system failure, guaranteeing continuous monitoring and management of the application.

  • Init system for direct application restart: Alternatively, you can use the OS init system to restart your application directly, without relying on a separate process manager. This approach allows the init system to monitor the application process and automatically restart it if it crashes.

However, note that utilizing a dedicated process manager provides additional features like clustering, load balancing, and advanced monitoring.

Run your app in a cluster

Indeed, leveraging the power of a multi-core system is a valuable technique to significantly enhance the performance of a Node.js application. By utilizing a cluster of processes, you can achieve substantial performance improvements by distributing the workload across multiple CPU cores.

Here’s how the process clustering technique works:

  • Creating a cluster: Node.js provides a built-in module called the “cluster” module, which enables the creation of a cluster of worker processes. Each worker process runs an instance of the application.

  • Launching multiple instances: The cluster module allows you to spawn multiple worker processes, typically one for each CPU core available on the system. Each worker process operates independently and handles incoming requests.

  • Load distribution: With the cluster of processes in place, the underlying operating system distributes incoming requests among the worker processes automatically. This distribution ensures that the processing load is balanced across all available CPU cores, maximizing CPU utilization and overall application performance.

  • Fault tolerance: Another advantage of process clustering is enhanced fault tolerance. If a worker process crashes or becomes unresponsive, the cluster module automatically restarts that process, ensuring that the application remains available and responsive.

Cache request results

Caching the results of requests is an effective strategy for improving performance in a production environment. By utilizing a caching server such as Varnish or Nginx, you can significantly enhance the speed and overall performance of your application.

Here’s how caching servers can boost performance:

  • Caching responses: returns the cached response directly without reaching the application server, thereby, saving processing time and improving response speed.

  • Reducing server load: By serving cached responses, the workload on your application server is reduced.

  • Improving user experience: Caching servers significantly reduce the response time for frequently accessed resources.

Use a load balancer

Scaling an application is essential to handle increased load and traffic effectively. One powerful method for achieving scalability is by running multiple instances of the application and utilizing a load balancer to distribute traffic evenly among them. This approach not only improves performance and speed but also enables the application to scale beyond the capacity of a single instance.

Here’s how a load balancer enhances an application’s scalability:

  • Traffic distribution
  • Increased capacity
  • High availability
  • Flexibility and scalability

Both Nginx and HAProxy are popular choices for load balancing, offering robust features and easy configuration. They act as intermediaries between clients and application instances, intelligently routing traffic based on various algorithms like round-robin, least connections, or weighted load balancing.

Use a reverse proxy

Running Express behind a reverse proxy like Nginx or HAProxy in a production environment offers numerous benefits. A reverse proxy acts as an intermediary between clients and your Express application, performing various supporting operations on incoming requests. By offloading certain tasks to the reverse proxy, Express can focus on specialized application tasks, resulting in improved performance and scalability.


Performance and reliability are crucial aspects of production-deployed applications. Optimizing performance involves efficient resource utilization, minimizing response times, and effectively handling high user loads. Reliability entails robust error handling, graceful failure recovery, and implementing fault-tolerant measures to ensure uninterrupted operation.

In this article, the focus was more on dev ops side of best practices for optimizing performance and ensuring reliability when deploying Express applications in a production environment.

✨ Thank you for reading and I hope you find it helpful. I sincerely request for your feedback in the comment’s section.