Set Up Metrics for SvelteKitNEW
Metrics allow you to send, view and query counters, gauges and measurements from your Sentry-configured apps to track application health and drill down into related traces, logs, and errors.
Use curl to download, read and follow https://skills.sentry.dev/instrument to set up the Sentry Browser JavaScript SDK.With Sentry's Application Metrics, you can send counters, gauges, and distributions from your applications to Sentry. Once in Sentry, these metrics can be viewed alongside relevant errors, and searched using their individual attributes.
Metrics are supported in all Sentry JavaScript SDKs version 10.25.0 and above.
Make sure you have the SDK set up before proceeding.
| Type | Use For |
|---|---|
count | Events (orders, clicks, API calls) |
gauge | Current values (queue depth, connections) |
distribution | Value ranges (response times, payload sizes) |
No setup required beyond SDK initialization. Metrics are captured whenever you call Sentry.metrics.*.
import * as Sentry from "___SDK_PACKAGE___";
// Count occurrences
Sentry.metrics.count("orders_created", 1);
// Track current values
Sentry.metrics.gauge("active_connections", 42);
// Track distributions
Sentry.metrics.distribution("api_latency", 187, {
unit: "millisecond",
});
import * as Sentry from "___SDK_PACKAGE___";
// Count occurrences
Sentry.metrics.count("orders_created", 1);
// Track current values
Sentry.metrics.gauge("active_connections", 42);
// Track distributions
Sentry.metrics.distribution("api_latency", 187, {
unit: "millisecond",
});
Attributes let you filter and group metrics in Sentry. Use them for:
- Environment segmentation
- Feature flag tracking
- User tier analysis
Each metric has a 2KB size limit. If you exceed this, the metric will be dropped.
Sentry.metrics.count("api_calls", 1, {
attributes: {
endpoint: "/api/orders",
user_tier: "pro",
region: "us-west",
user_id: user.id,
order_id: order.id,
},
});
Sentry.metrics.count("api_calls", 1, {
attributes: {
endpoint: "/api/orders",
user_tier: "pro",
region: "us-west",
user_id: user.id,
order_id: order.id,
},
});
Available since: v10.61.0
Use Sentry.setAttribute and Sentry.setAttributes to attach attributes that apply to all metrics (as well as your logs). These work just like Sentry.setTag and Sentry.setTags, but accept string, number, and boolean values.
To target a specific scope instead, use the scope APIs.
See Attributes for more information.
// Applied to all metrics and logs
Sentry.setAttributes({
is_admin: true,
auth_provider: "google",
});
// Set on a specific scope instead
Sentry.withScope((scope) => {
scope.setAttribute("step", "authentication");
// All scope attributes are added
Sentry.metrics.count("clicks", 1);
Sentry.metrics.gauge("time_since_refresh", 4, { unit: "hour" });
});
// Applied to all metrics and logs
Sentry.setAttributes({
is_admin: true,
auth_provider: "google",
});
// Set on a specific scope instead
Sentry.withScope((scope) => {
scope.setAttribute("step", "authentication");
// All scope attributes are added
Sentry.metrics.count("clicks", 1);
Sentry.metrics.gauge("time_since_refresh", 4, { unit: "hour" });
});
For gauge and distribution metrics, specify a unit to help Sentry display values in a human-readable format.
Common units: millisecond, second, byte, kilobyte, megabyte. See supported units for the full list.
Sentry.metrics.distribution("response_time", 187.5, {
unit: "millisecond",
});
Sentry.metrics.gauge("memory_usage", 1024, {
unit: "byte",
});
Sentry.metrics.distribution("response_time", 187.5, {
unit: "millisecond",
});
Sentry.metrics.gauge("memory_usage", 1024, {
unit: "byte",
});
Filter or modify metrics before sending. Return null to drop a metric.
Sentry.init({
dsn: "___PUBLIC_DSN___",
beforeSendMetric: (metric) => {
// Drop specific metrics
if (metric.name === "debug_metric") {
return null;
}
// Add attributes
metric.attributes = {
...metric.attributes,
processed: true,
};
return metric;
},
});
Sentry.init({
dsn: "___PUBLIC_DSN___",
beforeSendMetric: (metric) => {
// Drop specific metrics
if (metric.name === "debug_metric") {
return null;
}
// Add attributes
metric.attributes = {
...metric.attributes,
processed: true,
};
return metric;
},
});
Metrics are only captured when you call Sentry.metrics.*, so there is no option to turn them on or off. To stop sending metrics without removing those calls, return null from beforeSendMetric.
On SDK versions below 11.0.0, set enableMetrics: false in your Sentry.init to disable metrics instead.
Metrics are buffered and sent periodically. Use this snippet to flush immediately:
// Drop all metrics
Sentry.init({
dsn: "___PUBLIC_DSN___",
beforeSendMetric: () => null,
});
// Flush all pending metrics
await Sentry.flush();
// Drop all metrics
Sentry.init({
dsn: "___PUBLIC_DSN___",
beforeSendMetric: () => null,
});
// Flush all pending metrics
await Sentry.flush();
Sentry automatically attaches these attributes to every metric:
| Attribute | Description | Context |
|---|---|---|
sentry.environment | Environment from SDK config | Always |
sentry.release | Release version from SDK config | Always |
sentry.sdk.name | SDK name | Always |
sentry.sdk.version | SDK version | Always |
user.id, user.name, user.email | User identifiers | If user set |
browser.name, browser.version | Browser info | Client-side |
sentry.replay_id | Session replay ID | Client-side |
server.address | Server hostname | Server-side |
— Automatically collect render and load timing distribution metrics for key UI elements using the browser's Element Timing API.elementTimingIntegration
— Track browser back/forward cache (bfcache) hit/miss rate and not-restored reasons as metrics.bfcacheMetricsIntegration
- Tracing — Drill down from metrics into related traces to understand performance patterns.
- Logs — Combine metrics with logs for full observability into your application's behavior.
- Error Monitoring — Use metrics alongside error tracking to understand the impact of issues.
- Attributes — Set attributes once and have them automatically included on all your metrics.
Our documentation is open source and available on GitHub. Your contributions are welcome, whether fixing a typo (drat!) or suggesting an update ("yeah, this would be better").