From 6a00322d56765b4540368636cdda012c5f32d510 Mon Sep 17 00:00:00 2001
From: Abdelrahman Awad <abdelrahman.awad@sentry.io>
Date: Mon, 24 Aug 2026 16:06:08 -0400
Subject: [PATCH] feat(sveltekit): Register a route provider backed by reported
 route ids

SvelteKit has no public route matcher and `page.route.id` is not available
synchronously, so the provider answers from route ids the instrumentation has
already seen rather than by matching. Uses core's cached provider, so the
statefulness stays private and the API stays URL in, string out.
---
 .../src/client/browserTracingIntegration.ts       |  6 ++++++
 packages/sveltekit/src/client/routeCache.ts       | 15 +++++++++++++++
 .../sveltekit/src/client/svelte4BrowserTracing.ts |  5 +++++
 .../sveltekit/src/client/svelte5BrowserTracing.ts |  5 +++++
 4 files changed, 31 insertions(+)
 create mode 100644 packages/sveltekit/src/client/routeCache.ts

diff --git a/packages/sveltekit/src/client/browserTracingIntegration.ts b/packages/sveltekit/src/client/browserTracingIntegration.ts
index 3fb9b65bd1a7..fa1299f7ca77 100644
--- a/packages/sveltekit/src/client/browserTracingIntegration.ts
+++ b/packages/sveltekit/src/client/browserTracingIntegration.ts
@@ -1,5 +1,7 @@
 import type { Integration } from '@sentry/core';
+import { setRouteProvider } from '@sentry/core';
 import { browserTracingIntegration as originalBrowserTracingIntegration } from '@sentry/svelte';
+import { routeProvider } from './routeCache';
 // The `sentrySvelteKit()` Vite plugin redirects this to the Svelte 4 or Svelte 5 variant per Kit
 // version; without the plugin it resolves via `exports` to the Svelte 4 variant, so builds don't break.
 import { instrumentSvelteKitTracing } from '@sentry/sveltekit/browser-tracing-variant';
@@ -20,6 +22,10 @@ export function browserTracingIntegration(
 
   return {
     ...integration,
+    setup: client => {
+      setRouteProvider(routeProvider, client);
+      integration.setup?.(client);
+    },
     afterAllSetup: client => {
       integration.afterAllSetup(client);
       instrumentSvelteKitTracing(client, options);
diff --git a/packages/sveltekit/src/client/routeCache.ts b/packages/sveltekit/src/client/routeCache.ts
new file mode 100644
index 000000000000..ec61ee2741a2
--- /dev/null
+++ b/packages/sveltekit/src/client/routeCache.ts
@@ -0,0 +1,15 @@
+import { createCachedRouteProvider } from '@sentry/core';
+
+// SvelteKit has no public route matcher, and `page.route.id` is not available synchronously, so the
+// provider answers from route ids the instrumentation has already seen rather than by matching.
+export const routeProvider = createCachedRouteProvider();
+
+/**
+ * Records the parameterized route id SvelteKit reported for a path.
+ *
+ * Called from both the Kit 2 and Kit 3 instrumentation, since `page.route.id` is the only place the
+ * route id is available.
+ */
+export function recordRouteId(pathname: string | undefined, routeId: string | null | undefined): void {
+  routeProvider.record(pathname, routeId);
+}
diff --git a/packages/sveltekit/src/client/svelte4BrowserTracing.ts b/packages/sveltekit/src/client/svelte4BrowserTracing.ts
index 818a8ffe2f61..5dbfd4de479e 100644
--- a/packages/sveltekit/src/client/svelte4BrowserTracing.ts
+++ b/packages/sveltekit/src/client/svelte4BrowserTracing.ts
@@ -17,6 +17,7 @@ import type { Navigation, Page } from '@sveltejs/kit';
 // eslint-disable-next-line typescript/no-deprecated
 import { navigating, page } from '$app/stores';
 import type { Readable } from 'svelte/store';
+import { recordRouteId } from './routeCache';
 
 /**
  * SvelteKit 2 / Svelte 4 browser tracing (`$app/stores`). Selected at build time, so it's only
@@ -62,6 +63,8 @@ function _instrumentPageload(client: Client, pageStore: Readable<Page>): void {
 
     const routeId = pageState.route?.id;
 
+    recordRouteId(pageState.url?.pathname, routeId);
+
     if (routeId) {
       pageloadSpan.updateName(routeId);
       pageloadSpan.setAttributes({ [SEMANTIC_ATTRIBUTE_SENTRY_SOURCE]: 'route', [URL_TEMPLATE]: routeId });
@@ -105,6 +108,8 @@ function _instrumentNavigations(client: Client, navigatingStore: Readable<Naviga
     const parameterizedRouteOrigin = from?.route.id;
     const parameterizedRouteDestination = to?.route.id;
 
+    recordRouteId(to?.url.pathname, parameterizedRouteDestination);
+
     if (routingSpan) {
       // If a routing span is still open from a previous navigation, we finish it.
       routingSpan.end();
diff --git a/packages/sveltekit/src/client/svelte5BrowserTracing.ts b/packages/sveltekit/src/client/svelte5BrowserTracing.ts
index ca2e54c9e605..faade2f5d68a 100644
--- a/packages/sveltekit/src/client/svelte5BrowserTracing.ts
+++ b/packages/sveltekit/src/client/svelte5BrowserTracing.ts
@@ -15,6 +15,7 @@ import {
 import { SENTRY_OP, URL_TEMPLATE } from '@sentry/conventions/attributes';
 import type { Navigation } from '@sveltejs/kit';
 import { getCurrentNavigation, onNavigationChange, onPageRouteChange } from './navigationState.svelte';
+import { recordRouteId } from './routeCache';
 
 /**
  * SvelteKit 3 / Svelte 5 browser tracing (`$app/state` runes). Selected at build time, so it's only
@@ -55,6 +56,8 @@ function _instrumentPageLoad(client: Client): void {
   // `page.route.id` isn't available synchronously when we set up (during `Sentry.init`), so we react
   // to it and upgrade the pageload span from `url` to the parameterized `route` once it resolves.
   onPageRouteChange(routeId => {
+    recordRouteId(WINDOW.location?.pathname, routeId);
+
     if (routeId) {
       pageLoadSpan.updateName(routeId);
       pageLoadSpan.setAttributes({ [SEMANTIC_ATTRIBUTE_SENTRY_SOURCE]: 'route', [URL_TEMPLATE]: routeId });
@@ -88,6 +91,8 @@ function _instrumentNavigations(client: Client): void {
     const parameterizedRouteOrigin = from?.route.id;
     const parameterizedRouteDestination = to?.route.id;
 
+    recordRouteId(to?.url.pathname, parameterizedRouteDestination);
+
     routingSpan?.end();
 
     const navigationInfo = {