diff --git a/.changeset/keep-client-conditions.md b/.changeset/keep-client-conditions.md
new file mode 100644
index 000000000..0d8808ace
--- /dev/null
+++ b/.changeset/keep-client-conditions.md
@@ -0,0 +1,5 @@
+---
+"@solidjs/start": patch
+---
+
+Keep Vite's default resolve conditions ("module", "browser") in the client environment: since 2.1.0, packages exposing a "browser" export condition (e.g. `@sentry/solidstart`) resolved to their Node build in the browser. The dev overlay's `@jridgewell/trace-mapping` is now pre-bundled, as the "browser" condition makes it import a UMD build.
diff --git a/packages/start/src/config/index.spec.ts b/packages/start/src/config/index.spec.ts
index 4eec36f04..7f6650e43 100644
--- a/packages/start/src/config/index.spec.ts
+++ b/packages/start/src/config/index.spec.ts
@@ -81,3 +81,39 @@ describe("SERVER_BASE_URL", () => {
     await expect(serverBaseUrl({ base: "/app" }, command)).resolves.toBe("/app/");
   });
 });
+
+describe("resolve conditions", () => {
+  async function resolveEnvironments(command: ConfigEnv["command"] = "serve") {
+    const { resolveConfig } = await import("vite");
+    const config = await resolveConfig(
+      { root, logLevel: "silent", plugins: [solidStart()] },
+      command,
+      command === "build" ? "production" : "development",
+    );
+    return config.environments;
+  }
+
+  it("keeps Vite's client conditions", async () => {
+    const { client } = await resolveEnvironments();
+
+    expect(client.resolve.conditions).toEqual(expect.arrayContaining(["module", "browser"]));
+    expect(client.resolve.conditions).not.toContain("generic");
+  });
+
+  it("resolves the server to runtime-agnostic builds", async () => {
+    const { ssr } = await resolveEnvironments();
+
+    expect(ssr.resolve.conditions).toContain("generic");
+    expect(ssr.resolve.conditions).not.toContain("node");
+  });
+
+  it("pre-bundles the dev overlay's dependencies in dev only", async () => {
+    const dev = await resolveEnvironments("serve");
+    const build = await resolveEnvironments("build");
+
+    expect(dev.client.optimizeDeps.include).toContain("@solidjs/start > @jridgewell/trace-mapping");
+    expect(build.client.optimizeDeps.include ?? []).not.toContain(
+      "@solidjs/start > @jridgewell/trace-mapping",
+    );
+  });
+});
diff --git a/packages/start/src/config/index.ts b/packages/start/src/config/index.ts
index 3d5aa28e9..e8d09dde7 100644
--- a/packages/start/src/config/index.ts
+++ b/packages/start/src/config/index.ts
@@ -224,6 +224,11 @@ export interface SolidStartOptions {
   };
 }
 
+// The dev overlay is served unbundled (solid packages are excluded from
+// pre-bundling), and with the "browser" condition @jridgewell/trace-mapping
+// imports the UMD build of @jridgewell/resolve-uri, which has no ESM exports.
+const DEV_OVERLAY_DEPENDENCIES = ["@solidjs/start > @jridgewell/trace-mapping"];
+
 const absolute = (path: string, root: string) =>
   path ? (isAbsolute(path) ? path : join(root, path)) : path;
 
@@ -293,10 +298,16 @@ export function solidStart(options?: SolidStartOptions): Array<PluginOption> {
     {
       name: "solid-start:config",
       enforce: "pre",
-      configEnvironment(name) {
+      configEnvironment(name, config) {
+        // Setting resolve.conditions replaces Vite's defaults instead of extending
+        // them. Server environments drop "node" on purpose, so that h3 resolves to
+        // its runtime-agnostic build, but the client must keep "browser" and
+        // "module": without them, packages exposing a "browser" export condition
+        // resolve to their Node build in the browser.
+        const isClient = name === VITE_ENVIRONMENTS.client || config.consumer === "client";
         return {
           resolve: {
-            conditions: ["generic"],
+            ...(isClient ? {} : { conditions: ["generic"] }),
             // remove when https://github.com/solidjs/vite-plugin-solid/pull/228 is released
             externalConditions: ["solid", "node"],
           },
@@ -343,6 +354,9 @@ export function solidStart(options?: SolidStartOptions): Array<PluginOption> {
           environments: {
             [VITE_ENVIRONMENTS.client]: {
               consumer: "client",
+              ...(env.command === "serve" && start.devOverlay
+                ? { optimizeDeps: { include: DEV_OVERLAY_DEPENDENCIES } }
+                : {}),
               build: {
                 write: true,
                 manifest: true,