diff --git a/.changeset/exclude-start-from-server-prebundling.md b/.changeset/exclude-start-from-server-prebundling.md
new file mode 100644
index 000000000..b066f1581
--- /dev/null
+++ b/.changeset/exclude-start-from-server-prebundling.md
@@ -0,0 +1,5 @@
+---
+"@solidjs/start": patch
+---
+
+Keep `@solidjs/start` out of server pre-bundling, so that server functions no longer fail with "invalid server function" in dev with plugins that pre-bundle server dependencies, such as the Cloudflare Vite plugin.
diff --git a/packages/start/src/config/index.spec.ts b/packages/start/src/config/index.spec.ts
index 933ed4da8..6c67d6971 100644
--- a/packages/start/src/config/index.spec.ts
+++ b/packages/start/src/config/index.spec.ts
@@ -107,6 +107,12 @@ describe("resolve conditions", () => {
     expect(ssr.resolve.conditions).not.toContain("node");
   });
 
+  it("keeps @solidjs/start out of the server's pre-bundled dependencies", async () => {
+    const { ssr } = await resolveEnvironments();
+
+    expect(ssr.optimizeDeps.exclude).toContain("@solidjs/start");
+  });
+
   it("pre-bundles the dev overlay's dependencies in dev only", async () => {
     const dev = await resolveEnvironments("serve");
     const build = await resolveEnvironments("build");
diff --git a/packages/start/src/config/index.ts b/packages/start/src/config/index.ts
index 0883b7ff8..62ef1da0e 100644
--- a/packages/start/src/config/index.ts
+++ b/packages/start/src/config/index.ts
@@ -415,6 +415,9 @@ export function solidStart(options?: SolidStartOptions): Array<PluginOption> {
             },
             [VITE_ENVIRONMENTS.server]: {
               consumer: "server",
+              // Plugins that pre-bundle server dependencies, such as the Cloudflare Vite plugin,
+              // would otherwise load a second copy of the server function registry
+              optimizeDeps: { exclude: ["@solidjs/start"] },
               build: {
                 ssr: true,
                 write: true,