Imagine you are working on the best hosting for Node.js and potentially deploying a major update. But if there’s a Node.js application dropout during a request, it will affect users, leading to the most stressful hours when maintaining a website or service.
Even if your Node.js app doesn’t show an error and the server is technically “on,” your website might still be broken. Users can’t see any pages, and the system just hangs or stays stuck forever.
Before you start trying complicated fixes or restarting everything, stop and take a breath. Often, the problem is much simpler and more common than you think, especially in the case of a Windows RDP server.
This guide shows you the basic steps to check why your app isn’t working. It is written in a simple, easy-to-follow way that won’t feel overwhelming.
1. Check the state of app (running or stuck)
Contrary to popular assumption, just because your process is no longer responding doesn’t necessarily mean the process crashed; it may be alive but frozen in time. When an application “freezes,” it might look like a window that won’t move or click, or it might just crash completely and stop working.
It is essential to verify whether the Node process is alive on the hosting server. If the process no longer exists but requests are never completed, it’s likely the process is in a hung or blocked state.
If the process is no longer running, this is indicative of a crash or memory problem.
Understanding if your app is dead or simply unresponsive reduces your time spent on finding solutions.
2: Immediately check CPU and memory usage
Node apps need system resources to operate effectively.
If your CPU usage is pegged at 100%, your app may be looping or causing the process to hang or take longer than expected to complete. Because Node is single-threaded, one blocking task can cause the entire application to freeze up.
If your memory usage is extremely high or trending up, you are running out of memory. When this occurs, the performance of your Node app dramatically reduces. You don’t need to perform a true profiling of your app. Simply determine if the computer is working harder than it usually does.
3: Look for all unfinished requests
When a Node app becomes “non-responding,” it usually means that requests are hitting the app but have never finished processing.
The most common scenarios include:
- A long-running database query is hanging.
- An API call to an outside source that was made last week still hasn’t returned.
- A promise was made to the user and hasn’t been fulfilled.
When there are multiple incoming requests, and all are processed simultaneously, users assume that the app is still working. If you have access logs or raw request logs, check where and when they are processed. Even basic timestamps can allow you to see the time delay.
4. Inspect external dependencies and databases
A large number of Node.js applications rely on third-party services and databases as external dependencies.
An unresponsive, slow, or locked database causes a Node.js application to wait indefinitely for a response. The same applies to email services, payment gateways, or internal APIs.
In other words, your application is “fine,” but it is waiting for something else to complete.
You can do simple checks:
- Is the database server reachable?
- Are connection limits exceeded?
- Are external APIs experiencing timeouts?
The application will typically hang when these problems occur, even though the problem isn’t the application.
5. Review the last logs before the freeze
Log files are frequently forgotten until an issue arises. When an app gets stuck, look at the last messages it saved right before it slowed down. Even simple notes from the system can show you what went wrong—like a task that keeps repeating forever or a page that gets stuck trying to load.
Try to identify:
- Repeated error messages
- An unusually high number of warnings
- Log entries stopped illegally
6. Look for recent changes
Before problems start appearing, there are usually small warning signs before things actually break.
Questions to ask yourself:
- Was there a recent software deployment?
- Has there been an upgrade of a software dependency?
- Has there been an unexpected increase in website traffic?
- Has a configuration file been changed?
Even a minor alteration (missing the timeout on a function, adding an extra loop in code, or making a new call to an API service) can make your website crash completely once real people start using it.
7. Verify the process manager or container behavior
If you use a process manager or container to run your application, verify that it is managing your application as per your expectations. Some process managers and containers maintain the application in a restarting state, while others keep the apps in a running state.
Things to look at:
- Restart loops
- Health checks that have failed
- Resource limits that have been put in place by a container
8. Reboot the application and learn
Restarting your app might fix the problem for now, but it is only a temporary fix. If you don’t figure out why it broke, the same problem will definitely happen again. Hence, rebooting should be seen as a controlled event and not a reflex action.
Prior to restarting your application:
- Capture logs.
- Record resource usage.
- Identify stuck requests.
Key Reflections
Typically, when a Node application stops receiving input, it is just an issue that is shrouded in silence.
Most issues with a Node application are resolved through one of three main concerns:
- Blocking operations
- Lack of resources
- Non-responsive dependencies
So the easiest way to save time and reduce downtime is to check the simple things first before you try any difficult repairs.
Calm checks have always been superior to panic debugging. The objective of the troubleshooting tasks is not only to reactivate the application but also to investigate and resolve the problems for those applications that are unresponsive.