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---
title: PerformanceEntry
slug: Web/API/PerformanceEntry
page-type: web-api-interface
browser-compat: api.PerformanceEntry
---
{{APIRef("Performance API")}} {{AvailableInWorkers}}
The **`PerformanceEntry`** object encapsulates a single performance metric that is part of the browser's performance timeline.
The Performance API offers built-in metrics which are specialized subclasses of `PerformanceEntry`. This includes entries for resource loading, event timing, {{Glossary("first input delay")}} (FID), and more.
A performance entry can also be created by calling the {{domxref("Performance.mark()")}} or {{domxref("Performance.measure()")}} methods at an explicit point in an application. This allows you to add your own metrics to the performance timeline.
The `PerformanceEntry` instances will always be one of the following subclasses:
- {{domxref("LargestContentfulPaint")}}
- {{domxref("LayoutShift")}}
- {{domxref("PerformanceEventTiming")}}
- {{domxref("PerformanceLongAnimationFrameTiming")}}
- {{domxref("PerformanceLongTaskTiming")}}
- {{domxref("PerformanceMark")}}
- {{domxref("PerformanceMeasure")}}
- {{domxref("PerformanceNavigationTiming")}}
- {{domxref("PerformancePaintTiming")}}
- {{domxref("PerformanceResourceTiming")}}
- {{domxref("PerformanceScriptTiming")}}
- {{domxref("PerformanceServerTiming")}}
- {{domxref("TaskAttributionTiming")}}
- {{domxref("VisibilityStateEntry")}}
## Instance properties
- {{domxref("PerformanceEntry.name")}} {{ReadOnlyInline}}
- : A string representing the name for a performance entry. The value depends on the subtype.
- {{domxref("PerformanceEntry.entryType")}} {{ReadOnlyInline}}
- : A string representing the type of performance metric. For example, "`mark`" when {{domxref("PerformanceMark")}} is used.
- {{domxref("PerformanceEntry.startTime")}} {{ReadOnlyInline}}
- : A {{domxref("DOMHighResTimeStamp")}} representing the starting time for the performance metric.
- {{domxref("PerformanceEntry.duration")}} {{ReadOnlyInline}}
- : A {{domxref("DOMHighResTimeStamp")}} representing the duration of the performance entry.
## Instance methods
- {{domxref("PerformanceEntry.toJSON","PerformanceEntry.toJSON()")}}
- : Returns a JSON representation of the `PerformanceEntry` object.
## Example
### Working with performance entries
The following example creates `PerformanceEntry` objects that are of the types {{domxref("PerformanceMark")}} and {{domxref("PerformanceMeasure")}}.
The `PerformanceMark` and `PerformanceMeasure` subclasses inherit the `duration`, `entryType`, `name`, and `startTime` properties from `PerformanceEntry` and set them to their appropriate values.
```js
// Place at a location in the code that starts login
performance.mark("login-started");
// Place at a location in the code that finishes login
performance.mark("login-finished");
// Measure login duration
performance.measure("login-duration", "login-started", "login-finished");
function perfObserver(list, observer) {
list.getEntries().forEach((entry) => {
if (entry.entryType === "mark") {
console.log(`${entry.name}'s startTime: ${entry.startTime}`);
}
if (entry.entryType === "measure") {
console.log(`${entry.name}'s duration: ${entry.duration}`);
}
});
}
const observer = new PerformanceObserver(perfObserver);
observer.observe({ entryTypes: ["measure", "mark"] });
```
## Specifications
{{Specifications}}
## Browser compatibility
{{Compat}}