From 58a647e1b81a9f85218a672f6f9c982a61ab8aa3 Mon Sep 17 00:00:00 2001
From: Birk Skyum <birk.skyum@pm.me>
Date: Sun, 2 Aug 2026 02:14:45 +0200
Subject: [PATCH 1/2] fix: migrate build configs to Rolldown APIs

---
 apps/fixtures/css/vite.config.ts                 | 2 +-
 packages/start/src/config/app-root-alias.spec.ts | 2 +-
 packages/start/src/config/index.ts               | 6 +++---
 3 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/apps/fixtures/css/vite.config.ts b/apps/fixtures/css/vite.config.ts
index 95f97e4d8..efe9bf095 100644
--- a/apps/fixtures/css/vite.config.ts
+++ b/apps/fixtures/css/vite.config.ts
@@ -7,7 +7,7 @@ import virtualCSS from "./src/virtualCssPlugin";
 export default defineConfig({
   plugins: [virtualCSS(), solidStart(), nitro(), tailwindcss()],
   build: {
-    rollupOptions: {
+    rolldownOptions: {
       output: {
         /**
          * Creates a shared chunk with two components. Needed for the "SharedChunk" test!
diff --git a/packages/start/src/config/app-root-alias.spec.ts b/packages/start/src/config/app-root-alias.spec.ts
index 8680adf0f..9eaeeecc4 100644
--- a/packages/start/src/config/app-root-alias.spec.ts
+++ b/packages/start/src/config/app-root-alias.spec.ts
@@ -69,7 +69,7 @@ it("resolves ~ in stylesheets, which are resolved without user plugins", async (
     logLevel: "silent",
     root,
     plugins: [appRootAlias(root, "./src")],
-    build: { write: false, rollupOptions: { input: join(root, "src/main.js") } },
+    build: { write: false, rolldownOptions: { input: join(root, "src/main.js") } },
   })) as { output: { fileName: string; source?: unknown }[] };
 
   const css = result.output.find(chunk => chunk.fileName.endsWith(".css"));
diff --git a/packages/start/src/config/index.ts b/packages/start/src/config/index.ts
index c7ab08d65..9ad41a3f7 100644
--- a/packages/start/src/config/index.ts
+++ b/packages/start/src/config/index.ts
@@ -270,7 +270,7 @@ export function solidStart(options?: SolidStartOptions): Array<PluginOption> {
           appType: "custom",
           build: {
             assetsDir: "_build/assets",
-            rollupOptions: {
+            rolldownOptions: {
               output: {
                 // Keeps route chunks named after their file rather than after
                 // the `?pick=...` id that addresses them. See toPickId.
@@ -295,7 +295,7 @@ export function solidStart(options?: SolidStartOptions): Array<PluginOption> {
                 write: true,
                 manifest: true,
                 outDir: "dist/client",
-                rollupOptions: {
+                rolldownOptions: {
                   input: clientInput,
                   treeshake: true,
                   preserveEntrySignatures: "exports-only",
@@ -309,7 +309,7 @@ export function solidStart(options?: SolidStartOptions): Array<PluginOption> {
                 write: true,
                 manifest: true,
                 copyPublicDir: false,
-                rollupOptions: {
+                rolldownOptions: {
                   input: handlers.server,
                 },
                 outDir: "dist/server",

From b93e7be10c7812617e58c520b5f3f219c05fa3a1 Mon Sep 17 00:00:00 2001
From: Birk Skyum <birk.skyum@pm.me>
Date: Sun, 2 Aug 2026 02:22:22 +0200
Subject: [PATCH 2/2] chore: add changeset

---
 .changeset/fresh-tools-build.md | 5 +++++
 1 file changed, 5 insertions(+)
 create mode 100644 .changeset/fresh-tools-build.md

diff --git a/.changeset/fresh-tools-build.md b/.changeset/fresh-tools-build.md
new file mode 100644
index 000000000..7b21b616e
--- /dev/null
+++ b/.changeset/fresh-tools-build.md
@@ -0,0 +1,5 @@
+---
+"@solidjs/start": patch
+---
+
+Migrate the built-in Vite configuration from the deprecated `rollupOptions` alias to `rolldownOptions`.