Set Up Profiling

By default, Sentry error events will not get trace context unless you configure the scope with the transaction, as illustrated in the example below.

Installation

You have to install the @sentry/profiling-node package in addition to your main SDK package:

npm install @sentry/profiling-node --save

The version of the @sentry/profiling-node package must match the version of the main SDK package exactly.

Enabling Profiling

Profiling supports two modes - manual and trace. The two modes are mutually exclusive, and cannot be used at the same time.

In manual mode, the profiling data collection can be managed via calls to Sentry.profiler.startProfiler and Sentry.profiler.stopProfiler. You are entirely in the in control of when the profiler runs.

In trace mode, the profiler manages its own start and stop calls, which are based on spans: the profiler continues to run while there is at least one active span, and stops when there are no active spans.

Enabling Trace Lifecycle Profiling

To enable profiling, add @sentry/profiling-node to your imports and set up nodeProfilingIntegration in your Sentry config.

const { nodeProfilingIntegration } = require("@sentry/profiling-node");

Sentry.init({
  dsn: "https://examplePublicKey@o0.ingest.sentry.io/0",
  integrations: [
    // Add our Profiling integration
+   nodeProfilingIntegration(),
  ],
  tracesSampleRate: 1.0,
+ profileSessionSampleRate: 1.0,
+ profileLifecycle: 'trace',
});

// Profiling happens automatically after setting it up with `Sentry.init()`.
// All spans (unless those discarded by sampling) will have profiling data attached to them.
Sentry.startSpan(
  {
    op: "rootSpan",
    name: "My root span",
  },
  () => {
    // The code executed here will be profiled
  }
);

Enabling Manual Lifecycle Profiling

To enable profiling, add @sentry/profiling-node to your imports and set up nodeProfilingIntegration in your Sentry config.

const { nodeProfilingIntegration } = require("@sentry/profiling-node");

Sentry.init({
  dsn: "https://examplePublicKey@o0.ingest.sentry.io/0",
  integrations: [
    // Add our Profiling integration
+   nodeProfilingIntegration(),
  ],
  tracesSampleRate: 1.0,
+ profileSessionSampleRate: 1.0,
+ profileLifecycle: 'manual',
});

// All spans (unless those discarded by sampling) will have profiling data attached to them.
Sentry.profiler.startProfiler();
// Code executed between these two calls will be profiled
Sentry.profiler.stopProfiler();

Managing profile sampling rates

Sentry SDK supports an additional profileSessionSampleRate that will enable or disable profiling for the entire session. This can be used if you want to control session sampling rates at the service level as the sampling decision is evaluated only once at SDK init.

This is useful for cases where you deploy your service many times, but would only like a subset of those services to be profiled.

const { nodeProfilingIntegration } = require("@sentry/profiling-node");

Sentry.init({
  dsn: "https://examplePublicKey@o0.ingest.sentry.io/0",
  integrations: [
    // Add our Profiling integration
    nodeProfilingIntegration(),
  ],
  tracesSampleRate: 1.0,
+ profileSessionSampleRate: 0.0
});

How Does It Work?

Under the hood, the Sentry profiler uses V8's CpuProfiler to collect stack samples. This means that sentry/profiling-node is written as a native add-on for Node and won't run in environments like Deno or Bun. Profiling enhances tracing by providing profiles for individual transactions. This allows you to look at higher level performance information like transaction and span durations before diving deeper and looking at profiles.

Runtime Flags

There are three runtime flags you can set that control the behavior of the profiler. Two of the flags relate to how the SDK resolves the profiler binaries. The third alters how the underlying profiler is initialized by v8.

• SENTRY_PROFILER_BINARY_PATH

This flag sets the profiler binary path and bypasses arch, platform, and libc checks. It can be useful in some build configurations if you want to override which binary is required at runtime.

• SENTRY_PROFILER_BINARY_DIR

Acts similarly to the flag above, however, this flag only specifies the directory where the binaries are located and defers to the runtime to resolve the correct binary depending on the arch, platform, and libc version.

• SENTRY_PROFILER_LOGGING_MODE

The default mode of the v8 CpuProfiler is kEagerLogging, which enables the profiler even when no profiles are active—this is good because it makes calls to startProfgiler faster with the tradeoff of constant CPU overhead. This behavior can be controlled via the SENTRY_PROFILER_LOGGING_MODE environment variable with values of eager|lazy. If you opt to use the lazy-logging mode, calls to startProfiler may be slow. (Depending on environment and node version, it can be in the order of a few hundred ms.)

Here's an example of starting a server with lazy-logging mode:

# Run profiler in lazy mode
SENTRY_PROFILER_LOGGING_MODE=lazy node server.js

Precompiled Binaries

The @sentry/profiling-node package precompiles binaries for a number of common architectures. This minimizes the tooling required to run the package and avoids compiling the package from source in most cases, which speeds up installation. Currently, we ship prebuilt binaries for the following architectures and Node versions:

• macOS x64: Node v18, v20, v22, v24
• Linux ARM64 (musl): Node v18, v20, v22, v24
• Linux x64 (glibc): Node v18, v20, v22, v24
• Windows x64: Node v18, v20, v22, v24

The set of common architectures should cover a wide variety of use cases, but if you have feedback or experience different behavior, please open an issue in the Sentry JavaScript SDK repository.