StackImpact is a production-grade performance profiler built for both production and development environments. It gives developers continuous and historical view of application performance with line-of-code precision that is essential for locating CPU, memory allocation and async call hot spots as well as latency bottlenecks. Included runtime metric and error monitoring complement profiles for extensive performance analysis. Learn more at stackimpact.com.

• Continuous hot spot profiling for CPU, memory allocations, async calls
• Continuous latency bottleneck tracing
• Exception monitoring
• Health monitoring including CPU, memory, garbage collection and other runtime metrics
• Anomaly detection
• Multiple account users for team collaboration

Learn more on the features page (with screenshots).

See full documentation for reference.

• Linux, OS X or Windows. Node.js v4.0.0 or higher.
• CPU profiler is disabled by default for Node.js v7.0.0 to v8.9.3 due to memory leak in underlying V8's CPU profiler. To enable, add cpuProfilerDisabled: false to startup options.
• Allocation profiler supports Node.js v6.0.0 and higher. The allocation profiler is disabled by default, since V8's heap sampling is still experimental and is seen to result in segmentation faults. To enable, add allocationProfilerDisabled: false to startup options.
• Async profiler supports Node.js v8.1.0 and higher.

Sign up for a free trial account at stackimpact.com (also with GitHub login).

Install the Node.js agent by running

npm install stackimpact

And import the package in your application

const stackimpact = require('stackimpact');

Start the agent in the main thread by specifying the agent key and application name. The agent key can be found in your account's Configuration section.

const agent = stackimpact.start({
  agentKey: 'agent key here',
  appName: 'MyNodejsApp'
});

All initialization options:

• agentKey (Required) The API key for communication with the StackImpact servers.
• appName (Required) A name to identify and group application data. Typically, a single codebase, deployable unit or executable module corresponds to one application.
• appVersion (Optional) Sets application version, which can be used to associate profiling information with the source code release.
• appEnvironment (Optional) Used to differentiate applications in different environments.
• hostName (Optional) By default, host name will be the OS hostname.
• autoProfiling (Optional) If set to false, disables automatic profiling and reporting. agent.profile() and agent.report(callback) should be used instead. Useful for environments without support for timers or background tasks.
• debug (Optional) Enables debug logging.
• cpuProfilerDisabled, allocationProfilerDisabled, asyncProfilerDisabled, errorProfilerDisabled (Optional) Disables respective profiler when true.
• includeAgentFrames (Optional) Set to true to not exclude agent stack frames from profiles.

Optional

Use agent.profile() to instruct the agent when to start and stop profiling. The agent decides if and which profiler is activated. Normally, this method should be used in repeating code, such as request or event handlers. Usage example:

const span = agent.profile();

// your code here

span.stop();

Is no callback is provided, stop() method returns a promise.

Optional

Use agent.destroy() to stop the agent if necessary, e.g. to allow application to exit.

Once your application is restarted, you can start observing continuous CPU, memory, I/O, and other hot spot profiles, execution bottlenecks as well as process metrics in the Dashboard.

To enable debug logging, add debug: true to startup options. If the debug log doesn't give you any hints on how to fix a problem, please report it to our support team in your account's Support section.

The agent overhead is measured to be less than 1% for applications under high load. For applications that are horizontally scaled to multiple processes, StackImpact agents are only active on a small subset of the processes at any point of time, therefore the total overhead is much lower.