@@ -52,7 +52,7 @@ module.exports = [
 path: 'packages/browser/build/npm/esm/index.js',
 import: createImport('init', 'browserTracingIntegration', 'replayIntegration'),
 gzip: true,
-limit: '70.1 KB',
+limit: '71 KB',
 modifyWebpackConfig: function (config) {
 const webpack = require('webpack');
 
@@ -206,7 +206,7 @@ module.exports = [
 import: createImport('init'),
 ignore: ['next/router', 'next/constants'],
 gzip: true,
-limit: '42 KB',
+limit: '42.5 KB',
 },
 // SvelteKit SDK (ESM)
 {

@@ -1,10 +1,11 @@
 /* eslint-disable max-lines */
-import type { Measurements, Span, SpanAttributes, StartSpanOptions } from '@sentry/core';
+import type { Measurements, Span, SpanAttributes, SpanAttributeValue, StartSpanOptions } from '@sentry/core';
 import {
 browserPerformanceTimeOrigin,
 getActiveSpan,
 getComponentName,
 htmlTreeAsString,
+isPrimitive,
 parseUrl,
 SEMANTIC_ATTRIBUTE_SENTRY_ORIGIN,
 setMeasurement,
@@ -339,7 +340,7 @@ export function addPerformanceEntries(span: Span, options: AddPerformanceEntries
 case 'mark':
 case 'paint':
 case 'measure': {
-_addMeasureSpans(span, entry, startTime, duration, timeOrigin);
+_addMeasureSpans(span, entry as PerformanceMeasure, startTime, duration, timeOrigin);
 
 // capture web vitals
 const firstHidden = getVisibilityWatcher();
@@ -421,7 +422,7 @@ export function addPerformanceEntries(span: Span, options: AddPerformanceEntries
 */
 export function _addMeasureSpans(
 span: Span,
-entry: PerformanceEntry,
+entry: PerformanceMeasure,
 startTime: number,
 duration: number,
 timeOrigin: number,
@@ -450,6 +451,34 @@ export function _addMeasureSpans(
 attributes['sentry.browser.measure_start_time'] = measureStartTimestamp;
 }
 
+// https://developer.mozilla.org/en-US/docs/Web/API/Performance/measure#detail
+if (entry.detail) {
+// Handle detail as an object
+if (typeof entry.detail === 'object') {
+for (const [key, value] of Object.entries(entry.detail)) {
+if (value && isPrimitive(value)) {
+attributes[`sentry.browser.measure.detail.${key}`] = value as SpanAttributeValue;
+} else {
+try {
+// This is user defined so we can't guarantee it's serializable
+attributes[`sentry.browser.measure.detail.${key}`] = JSON.stringify(value);
+} catch {
+// skip
+}
+}
+}
+} else if (isPrimitive(entry.detail)) {
+attributes['sentry.browser.measure.detail'] = entry.detail as SpanAttributeValue;
+} else {
+// This is user defined so we can't guarantee it's serializable
+try {
+attributes['sentry.browser.measure.detail'] = JSON.stringify(entry.detail);
+} catch {
+// skip
+}
+}
+}
+
 // Measurements from third parties can be off, which would create invalid spans, dropping transactions in the process.
 if (measureStartTimestamp <= measureEndTimestamp) {
 startAndEndSpan(span, measureStartTimestamp, measureEndTimestamp, {

@@ -70,7 +70,8 @@ describe('_addMeasureSpans', () => {
 name: 'measure-1',
 duration: 10,
 startTime: 12,
-} as PerformanceEntry;
+detail: null,
+} as PerformanceMeasure;
 
 const timeOrigin = 100;
 const startTime = 23;
@@ -106,7 +107,8 @@ describe('_addMeasureSpans', () => {
 name: 'measure-1',
 duration: 10,
 startTime: 12,
-} as PerformanceEntry;
+detail: null,
+} as PerformanceMeasure;
 
 const timeOrigin = 100;
 const startTime = 23;
@@ -116,6 +118,165 @@ describe('_addMeasureSpans', () => {
 
 expect(spans).toHaveLength(0);
 });
+
+it('adds measure spans with primitive detail', () => {
+const spans: Span[] = [];
+
+getClient()?.on('spanEnd', span => {
+spans.push(span);
+});
+
+const entry = {
+entryType: 'measure',
+name: 'measure-1',
+duration: 10,
+startTime: 12,
+detail: 'test-detail',
+} as PerformanceMeasure;
+
+const timeOrigin = 100;
+const startTime = 23;
+const duration = 356;
+
+_addMeasureSpans(span, entry, startTime, duration, timeOrigin);
+
+expect(spans).toHaveLength(1);
+expect(spanToJSON(spans[0]!)).toEqual(
+expect.objectContaining({
+description: 'measure-1',
+start_timestamp: timeOrigin + startTime,
+timestamp: timeOrigin + startTime + duration,
+op: 'measure',
+origin: 'auto.resource.browser.metrics',
+data: {
+[SEMANTIC_ATTRIBUTE_SENTRY_OP]: 'measure',
+[SEMANTIC_ATTRIBUTE_SENTRY_ORIGIN]: 'auto.resource.browser.metrics',
+'sentry.browser.measure.detail': 'test-detail',
+},
+}),
+);
+});
+
+it('adds measure spans with object detail', () => {
+const spans: Span[] = [];
+
+getClient()?.on('spanEnd', span => {
+spans.push(span);
+});
+
+const detail = {
+component: 'Button',
+action: 'click',
+metadata: { id: 123 },
+};
+
+const entry = {
+entryType: 'measure',
+name: 'measure-1',
+duration: 10,
+startTime: 12,
+detail,
+} as PerformanceMeasure;
+
+const timeOrigin = 100;
+const startTime = 23;
+const duration = 356;
+
+_addMeasureSpans(span, entry, startTime, duration, timeOrigin);
+
+expect(spans).toHaveLength(1);
+expect(spanToJSON(spans[0]!)).toEqual(
+expect.objectContaining({
+description: 'measure-1',
+start_timestamp: timeOrigin + startTime,
+timestamp: timeOrigin + startTime + duration,
+op: 'measure',
+origin: 'auto.resource.browser.metrics',
+data: {
+[SEMANTIC_ATTRIBUTE_SENTRY_OP]: 'measure',
+[SEMANTIC_ATTRIBUTE_SENTRY_ORIGIN]: 'auto.resource.browser.metrics',
+'sentry.browser.measure.detail.component': 'Button',
+'sentry.browser.measure.detail.action': 'click',
+'sentry.browser.measure.detail.metadata': JSON.stringify({ id: 123 }),
+},
+}),
+);
+});
+
+it('handles non-primitive detail values by stringifying them', () => {
+const spans: Span[] = [];
+
+getClient()?.on('spanEnd', span => {
+spans.push(span);
+});
+
+const detail = {
+component: 'Button',
+action: 'click',
+metadata: { id: 123 },
+callback: () => {},
+};
+
+const entry = {
+entryType: 'measure',
+name: 'measure-1',
+duration: 10,
+startTime: 12,
+detail,
+} as PerformanceMeasure;
+
+const timeOrigin = 100;
+const startTime = 23;
+const duration = 356;
+
+_addMeasureSpans(span, entry, startTime, duration, timeOrigin);
+
+expect(spans).toHaveLength(1);
+const spanData = spanToJSON(spans[0]!).data;
+expect(spanData['sentry.browser.measure.detail.component']).toBe('Button');
+expect(spanData['sentry.browser.measure.detail.action']).toBe('click');
+expect(spanData['sentry.browser.measure.detail.metadata']).toBe(JSON.stringify({ id: 123 }));
+expect(spanData['sentry.browser.measure.detail.callback']).toBe(JSON.stringify(detail.callback));
+});
+
+it('handles errors in object detail value stringification', () => {
+const spans: Span[] = [];
+
+getClient()?.on('spanEnd', span => {
+spans.push(span);
+});
+
+const circular: any = {};
+circular.self = circular;
+
+const detail = {
+component: 'Button',
+action: 'click',
+circular,
+};
+
+const entry = {
+entryType: 'measure',
+name: 'measure-1',
+duration: 10,
+startTime: 12,
+detail,
+} as PerformanceMeasure;
+
+const timeOrigin = 100;
+const startTime = 23;
+const duration = 356;
+
+// Should not throw
+_addMeasureSpans(span, entry, startTime, duration, timeOrigin);
+
+expect(spans).toHaveLength(1);
+const spanData = spanToJSON(spans[0]!).data;
+expect(spanData['sentry.browser.measure.detail.component']).toBe('Button');
+expect(spanData['sentry.browser.measure.detail.action']).toBe('click');
+// The circular reference should be skipped
+expect(spanData['sentry.browser.measure.detail.circular']).toBeUndefined();
+});
 });
 
 describe('_addResourceSpans', () => {
@@ -464,7 +625,6 @@ describe('_addNavigationSpans', () => {
 transferSize: 14726,
 encodedBodySize: 14426,
 decodedBodySize: 67232,
-responseStatus: 200,
 serverTiming: [],
 unloadEventStart: 0,
 unloadEventEnd: 0,