diff --git a/.changeset/sad-actors-relax.md b/.changeset/sad-actors-relax.md
new file mode 100644
index 000000000..d425d09f3
--- /dev/null
+++ b/.changeset/sad-actors-relax.md
@@ -0,0 +1,6 @@
+---
+'@sveltejs/vite-plugin-svelte-inspector': patch
+'@sveltejs/vite-plugin-svelte': patch
+---
+
+perf: switch from debug to obug (smaller, esm-only)
diff --git a/packages/vite-plugin-svelte-inspector/package.json b/packages/vite-plugin-svelte-inspector/package.json
index b70efe57d..92c7f2157 100644
--- a/packages/vite-plugin-svelte-inspector/package.json
+++ b/packages/vite-plugin-svelte-inspector/package.json
@@ -39,7 +39,7 @@
   },
   "homepage": "https://github.com/sveltejs/vite-plugin-svelte#readme",
   "dependencies": {
-    "debug": "^4.4.3"
+    "obug": "^2.1.0"
   },
   "peerDependencies": {
     "@sveltejs/vite-plugin-svelte": "^6.0.0-next.0",
diff --git a/packages/vite-plugin-svelte-inspector/src/debug.js b/packages/vite-plugin-svelte-inspector/src/debug.js
index 0575a83fd..82554e6a8 100644
--- a/packages/vite-plugin-svelte-inspector/src/debug.js
+++ b/packages/vite-plugin-svelte-inspector/src/debug.js
@@ -1,3 +1,3 @@
-import _debug from 'debug';
+import { createDebug } from 'obug';
 
-export const debug = _debug('vite-plugin-svelte-inspector');
+export const debug = createDebug('vite-plugin-svelte-inspector');
diff --git a/packages/vite-plugin-svelte/package.json b/packages/vite-plugin-svelte/package.json
index 4b329a87e..19573911d 100644
--- a/packages/vite-plugin-svelte/package.json
+++ b/packages/vite-plugin-svelte/package.json
@@ -40,9 +40,9 @@
   "homepage": "https://github.com/sveltejs/vite-plugin-svelte#readme",
   "dependencies": {
     "@sveltejs/vite-plugin-svelte-inspector": "^5.0.0",
-    "debug": "^4.4.3",
     "deepmerge": "^4.3.1",
     "magic-string": "^0.30.21",
+    "obug": "^2.1.0",
     "vitefu": "^1.1.1"
   },
   "peerDependencies": {
diff --git a/packages/vite-plugin-svelte/src/utils/log.js b/packages/vite-plugin-svelte/src/utils/log.js
index 61b32bc82..663cb8bb1 100644
--- a/packages/vite-plugin-svelte/src/utils/log.js
+++ b/packages/vite-plugin-svelte/src/utils/log.js
@@ -6,7 +6,7 @@ const cyan = (/** @type {string} */ txt) => styleText('cyan', txt);
 const yellow = (/** @type {string} */ txt) => styleText('yellow', txt);
 const red = (/** @type {string} */ txt) => styleText('red', txt);
 
-import debug from 'debug';
+import { createDebug, enabled } from 'obug';
 
 /** @type {import('../types/log.d.ts').LogLevel[]} */
 const levels = ['debug', 'info', 'warn', 'error', 'silent'];
@@ -14,7 +14,7 @@ const prefix = 'vite-plugin-svelte';
 /** @type {Record<import('../types/log.d.ts').LogLevel, any>} */
 const loggers = {
 	debug: {
-		log: debug(`${prefix}`),
+		log: createDebug(`${prefix}`),
 		enabled: false,
 		isDebug: true
 	},
@@ -252,5 +252,5 @@ export function buildExtendedLogMessage(w) {
  * @returns {boolean}
  */
 export function isDebugNamespaceEnabled(namespace) {
-	return debug.enabled(`${prefix}:${namespace}`);
+	return enabled(`${prefix}:${namespace}`);
 }
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 1d8fc639b..7a93393fd 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -710,15 +710,15 @@ importers:
       '@sveltejs/vite-plugin-svelte-inspector':
         specifier: workspace:^
         version: link:../vite-plugin-svelte-inspector
-      debug:
-        specifier: ^4.4.3
-        version: 4.4.3
       deepmerge:
         specifier: ^4.3.1
         version: 4.3.1
       magic-string:
         specifier: ^0.30.21
         version: 0.30.21
+      obug:
+        specifier: ^2.1.0
+        version: 2.1.1
       vitefu:
         specifier: ^1.1.1
         version: 1.1.1(vite@7.2.6(@types/node@22.19.1)(sass@1.94.2)(stylus@0.64.0)(yaml@2.8.2))
@@ -741,9 +741,9 @@ importers:
       '@sveltejs/vite-plugin-svelte':
         specifier: workspace:^
         version: link:../vite-plugin-svelte
-      debug:
-        specifier: ^4.4.3
-        version: 4.4.3
+      obug:
+        specifier: ^2.1.0
+        version: 2.1.1
     devDependencies:
       '@types/debug':
         specifier: ^4.1.12