diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 6a347f9da..0e65c386a 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -5,6 +5,7 @@ on:
     branches: [main]
   pull_request:
     branches: [main]
+    types: [opened, synchronize, reopened, labeled]
   workflow_call:
 
 jobs:
@@ -23,10 +24,13 @@ jobs:
       - run: pnpm check
 
   test:
-    runs-on: blacksmith-4vcpu-ubuntu-2404
+    runs-on: ${{ matrix.os }}
     strategy:
       fail-fast: false
       matrix:
+        # Windows runs on main pushes and PRs labeled "test: windows"
+        os: '${{ (github.event_name == ''push'' || contains(github.event.pull_request.labels.*.name, ''test: windows'')) && fromJSON(''["blacksmith-4vcpu-ubuntu-2404","windows-latest"]'') || fromJSON(''["blacksmith-4vcpu-ubuntu-2404"]'') }}'
+        suite: [unit, core-markdown, metaframeworks, pages-react-vue, pages-svelte-solid]
         include:
           - suite: unit
             script: test:unit
@@ -52,6 +56,19 @@ jobs:
       - run: pnpm build
 
       - run: pnpm exec playwright install --with-deps chromium
-        if: matrix.suite == 'core-markdown' || matrix.suite == 'metaframeworks' || startsWith(matrix.suite, 'pages-')
+        if: matrix.suite != 'unit' && !contains(matrix.os, 'windows')
+
+      - run: pnpm exec playwright install chromium
+        if: matrix.suite != 'unit' && contains(matrix.os, 'windows')
 
       - run: pnpm ${{ matrix.script }}${{ matrix.retry && format(' --retry {0}', matrix.retry) || '' }}
+
+  done:
+    runs-on: ubuntu-latest
+    if: always()
+    needs:
+      - lint-and-check
+      - test
+    steps:
+      - run: exit 1
+        if: ${{ contains(needs.*.result, 'failure') || contains(needs.*.result, 'cancelled') }}
diff --git a/package.json b/package.json
index d2e62c12e..6f093b41d 100644
--- a/package.json
+++ b/package.json
@@ -21,7 +21,9 @@
     "test": "vitest --run"
   },
   "devDependencies": {
+    "@types/cross-spawn": "^6.0.6",
     "@typescript/native-preview": "catalog:",
+    "cross-spawn": "^7.0.6",
     "husky": "^9.1.7",
     "lint-staged": "^16.4.0",
     "oxfmt": "^0.42.0",
diff --git a/packages/md/test/integration/markdown-blog.test.ts b/packages/md/test/integration/markdown-blog.test.ts
index 5e26a2f54..e34300363 100644
--- a/packages/md/test/integration/markdown-blog.test.ts
+++ b/packages/md/test/integration/markdown-blog.test.ts
@@ -1,5 +1,6 @@
 import { describe, expect, it, beforeAll, afterAll } from "vitest";
-import { execSync, spawn } from "node:child_process";
+import { execSync } from "node:child_process";
+import spawn from "cross-spawn";
 import { join } from "node:path";
 import { chromium, type Browser, type Page } from "playwright";
 import { getPort, waitForServer, killChild } from "../../../../test/integration-helpers";
diff --git a/packages/react/test/integration/react-pages-client.test.ts b/packages/react/test/integration/react-pages-client.test.ts
index f72261523..820a6f3ea 100644
--- a/packages/react/test/integration/react-pages-client.test.ts
+++ b/packages/react/test/integration/react-pages-client.test.ts
@@ -1,5 +1,6 @@
 import { describe, expect, it, beforeAll, afterAll } from "vitest";
-import { execSync, spawn } from "node:child_process";
+import { execSync } from "node:child_process";
+import spawn from "cross-spawn";
 import { join } from "node:path";
 import { readFileSync, writeFileSync } from "node:fs";
 import { chromium, type Browser, type Page } from "playwright";
diff --git a/packages/solid/test/integration/solid-pages-playground.test.ts b/packages/solid/test/integration/solid-pages-playground.test.ts
index 5f5ebb150..df2177541 100644
--- a/packages/solid/test/integration/solid-pages-playground.test.ts
+++ b/packages/solid/test/integration/solid-pages-playground.test.ts
@@ -1,5 +1,6 @@
 import { afterAll, beforeAll, describe, expect, it } from "vitest";
-import { execSync, spawn } from "node:child_process";
+import { execSync } from "node:child_process";
+import spawn from "cross-spawn";
 import { join } from "node:path";
 import { readFileSync, writeFileSync } from "node:fs";
 import { chromium, type Browser, type Page } from "playwright";
diff --git a/packages/svelte/test/integration/svelte-pages-client.test.ts b/packages/svelte/test/integration/svelte-pages-client.test.ts
index a207401ba..e128c9807 100644
--- a/packages/svelte/test/integration/svelte-pages-client.test.ts
+++ b/packages/svelte/test/integration/svelte-pages-client.test.ts
@@ -1,5 +1,6 @@
 import { describe, expect, it, beforeAll, afterAll } from "vitest";
-import { execSync, spawn } from "node:child_process";
+import { execSync } from "node:child_process";
+import spawn from "cross-spawn";
 import { join } from "node:path";
 import { readFileSync, writeFileSync } from "node:fs";
 import { chromium, type Browser, type Page } from "playwright";
diff --git a/packages/void/test/integration/astro.test.ts b/packages/void/test/integration/astro.test.ts
index 1989ea024..4fb4858d7 100644
--- a/packages/void/test/integration/astro.test.ts
+++ b/packages/void/test/integration/astro.test.ts
@@ -1,5 +1,6 @@
 import { afterAll, beforeAll, describe, expect, it } from "vitest";
-import { execSync, spawn } from "node:child_process";
+import { execSync } from "node:child_process";
+import spawn from "cross-spawn";
 import { existsSync, readFileSync, rmSync } from "node:fs";
 import { join } from "node:path";
 import { getPort, waitForServer, killChild } from "../../../../test/integration-helpers";
diff --git a/packages/void/test/integration/kitchen-sink-build.test.ts b/packages/void/test/integration/kitchen-sink-build.test.ts
index 00a15db39..60e6d6821 100644
--- a/packages/void/test/integration/kitchen-sink-build.test.ts
+++ b/packages/void/test/integration/kitchen-sink-build.test.ts
@@ -1,7 +1,8 @@
 import { beforeAll, describe, expect, it } from "vitest";
-import { spawnSync } from "node:child_process";
+import spawn from "cross-spawn";
 import { existsSync, readFileSync, readdirSync, rmSync } from "node:fs";
 import { join } from "node:path";
+import { toSlash } from "../../src/shared/utils";
 
 const ROOT = join(import.meta.dirname, "..", "..", "..", "..");
 const PLAYGROUND = "playground/kitchen-sink";
@@ -15,7 +16,7 @@ describe("playground/kitchen-sink build", () => {
     rmSync(join(pg, "dist"), { recursive: true, force: true });
     rmSync(join(pg, ".void"), { recursive: true, force: true });
 
-    const result = spawnSync("pnpm", ["--dir", PLAYGROUND, "build"], {
+    const result = spawn.sync("pnpm", ["--dir", PLAYGROUND, "build"], {
       cwd: ROOT,
       encoding: "utf8",
       maxBuffer: 10 * 1024 * 1024,
@@ -51,7 +52,7 @@ describe("playground/kitchen-sink build", () => {
 function collectFiles(dir: string): string[] {
   const files: string[] = [];
   for (const entry of readdirSync(dir, { withFileTypes: true })) {
-    const entryPath = join(dir, entry.name);
+    const entryPath = toSlash(join(dir, entry.name));
     if (entry.isDirectory()) {
       files.push(...collectFiles(entryPath));
     } else {
diff --git a/packages/void/test/integration/kitchen-sink.test.ts b/packages/void/test/integration/kitchen-sink.test.ts
index 2b9619fb4..351095e31 100644
--- a/packages/void/test/integration/kitchen-sink.test.ts
+++ b/packages/void/test/integration/kitchen-sink.test.ts
@@ -1,5 +1,6 @@
 import { describe, expect, it, beforeAll, afterAll } from "vitest";
-import { execSync, spawn } from "node:child_process";
+import { execSync } from "node:child_process";
+import spawn from "cross-spawn";
 import { join } from "node:path";
 import { rmSync } from "node:fs";
 import { chromium, type Browser, type Page } from "playwright";
diff --git a/packages/void/test/integration/named-layouts.test.ts b/packages/void/test/integration/named-layouts.test.ts
index a7ab1c76e..b9a802402 100644
--- a/packages/void/test/integration/named-layouts.test.ts
+++ b/packages/void/test/integration/named-layouts.test.ts
@@ -1,5 +1,5 @@
 import { describe, expect, it, beforeAll, afterAll } from "vitest";
-import { spawn } from "node:child_process";
+import spawn from "cross-spawn";
 import { join } from "node:path";
 import { getPort, waitForServer, killChild } from "../../../../test/integration-helpers";
 
diff --git a/packages/void/test/integration/node-target.test.ts b/packages/void/test/integration/node-target.test.ts
index fec409d8e..d7645fd3b 100644
--- a/packages/void/test/integration/node-target.test.ts
+++ b/packages/void/test/integration/node-target.test.ts
@@ -1,10 +1,11 @@
 import { afterAll, beforeAll, describe, expect, it } from "vitest";
-import { execSync, spawn } from "node:child_process";
+import { execSync } from "node:child_process";
+import spawn from "cross-spawn";
 import { existsSync, readFileSync, rmSync } from "node:fs";
 import { join } from "node:path";
 import { getPort, waitForServer, killChild } from "../../../../test/integration-helpers";
 
-const ROOT = new URL("../../../..", import.meta.url).pathname;
+const ROOT = join(import.meta.dirname, "..", "..", "..", "..");
 let DEV_PORT: number;
 let DEV_BASE: string;
 let PROD_PORT: number;
diff --git a/packages/void/test/integration/nuxt.test.ts b/packages/void/test/integration/nuxt.test.ts
index 408aa127b..409aa7b72 100644
--- a/packages/void/test/integration/nuxt.test.ts
+++ b/packages/void/test/integration/nuxt.test.ts
@@ -1,5 +1,6 @@
 import { afterAll, beforeAll, describe, expect, it } from "vitest";
-import { execSync, spawn } from "node:child_process";
+import { execSync } from "node:child_process";
+import spawn from "cross-spawn";
 import { existsSync, readFileSync, rmSync } from "node:fs";
 import { join } from "node:path";
 import { getPort, waitForServer, killChild } from "../../../../test/integration-helpers";
diff --git a/packages/void/test/integration/pg-test.test.ts b/packages/void/test/integration/pg-test.test.ts
index 1f8c571a3..a9999ced4 100644
--- a/packages/void/test/integration/pg-test.test.ts
+++ b/packages/void/test/integration/pg-test.test.ts
@@ -1,6 +1,6 @@
 import { afterAll, beforeAll, describe, expect, it } from "vitest";
 import { readFileSync, writeFileSync, unlinkSync } from "node:fs";
-import { spawn } from "node:child_process";
+import spawn from "cross-spawn";
 import { join } from "node:path";
 import { once } from "node:events";
 import { PGlite } from "@electric-sql/pglite";
diff --git a/packages/void/test/integration/react-router.test.ts b/packages/void/test/integration/react-router.test.ts
index 41cf9561d..0b0b22384 100644
--- a/packages/void/test/integration/react-router.test.ts
+++ b/packages/void/test/integration/react-router.test.ts
@@ -1,5 +1,6 @@
 import { afterAll, beforeAll, describe, expect, it } from "vitest";
-import { execSync, spawn } from "node:child_process";
+import { execSync } from "node:child_process";
+import spawn from "cross-spawn";
 import { existsSync, readFileSync, rmSync } from "node:fs";
 import { join } from "node:path";
 import { getPort, waitForServer, killChild } from "../../../../test/integration-helpers";
diff --git a/packages/void/test/integration/ssr-playground.test.ts b/packages/void/test/integration/ssr-playground.test.ts
index e0355d3e2..23570e219 100644
--- a/packages/void/test/integration/ssr-playground.test.ts
+++ b/packages/void/test/integration/ssr-playground.test.ts
@@ -1,5 +1,6 @@
 import { afterAll, beforeAll, describe, expect, it } from "vitest";
-import { execSync, spawn } from "node:child_process";
+import { execSync } from "node:child_process";
+import spawn from "cross-spawn";
 import { existsSync, readFileSync, rmSync } from "node:fs";
 import { join } from "node:path";
 import { getPort, waitForServer, killChild } from "../../../../test/integration-helpers";
diff --git a/packages/void/test/integration/sveltekit.test.ts b/packages/void/test/integration/sveltekit.test.ts
index 14276e368..f77840987 100644
--- a/packages/void/test/integration/sveltekit.test.ts
+++ b/packages/void/test/integration/sveltekit.test.ts
@@ -1,5 +1,6 @@
 import { afterAll, beforeAll, describe, expect, it } from "vitest";
-import { execSync, spawn } from "node:child_process";
+import { execSync } from "node:child_process";
+import spawn from "cross-spawn";
 import { existsSync, readFileSync, rmSync, writeFileSync } from "node:fs";
 import { join } from "node:path";
 import { getPort, waitForServer, killChild } from "../../../../test/integration-helpers";
diff --git a/packages/void/test/integration/tanstack-start.test.ts b/packages/void/test/integration/tanstack-start.test.ts
index c3df6298e..db17784df 100644
--- a/packages/void/test/integration/tanstack-start.test.ts
+++ b/packages/void/test/integration/tanstack-start.test.ts
@@ -1,5 +1,6 @@
 import { afterAll, beforeAll, describe, expect, it } from "vitest";
-import { execSync, spawn } from "node:child_process";
+import { execSync } from "node:child_process";
+import spawn from "cross-spawn";
 import { existsSync, readFileSync, rmSync } from "node:fs";
 import { join } from "node:path";
 import { getPort, waitForServer, killChild } from "../../../../test/integration-helpers";
diff --git a/packages/void/test/integration/vinext-app.test.ts b/packages/void/test/integration/vinext-app.test.ts
index 57c6e317a..e59d3c2aa 100644
--- a/packages/void/test/integration/vinext-app.test.ts
+++ b/packages/void/test/integration/vinext-app.test.ts
@@ -1,5 +1,6 @@
 import { afterAll, beforeAll, describe, expect, it } from "vitest";
-import { execSync, spawn } from "node:child_process";
+import { execSync } from "node:child_process";
+import spawn from "cross-spawn";
 import { existsSync, readFileSync, rmSync } from "node:fs";
 import { join } from "node:path";
 import { getPort, waitForServer, killChild } from "../../../../test/integration-helpers";
diff --git a/packages/void/test/integration/vinext-pages.test.ts b/packages/void/test/integration/vinext-pages.test.ts
index a63fe7bc1..e05ca8f40 100644
--- a/packages/void/test/integration/vinext-pages.test.ts
+++ b/packages/void/test/integration/vinext-pages.test.ts
@@ -1,5 +1,6 @@
 import { afterAll, beforeAll, describe, expect, it } from "vitest";
-import { execSync, spawn } from "node:child_process";
+import { execSync } from "node:child_process";
+import spawn from "cross-spawn";
 import { existsSync, readFileSync, rmSync } from "node:fs";
 import { join } from "node:path";
 import { getPort, waitForServer, killChild } from "../../../../test/integration-helpers";
diff --git a/packages/void/test/integration/websockets-playground.test.ts b/packages/void/test/integration/websockets-playground.test.ts
index 0c0007864..d3bc5cc30 100644
--- a/packages/void/test/integration/websockets-playground.test.ts
+++ b/packages/void/test/integration/websockets-playground.test.ts
@@ -1,5 +1,5 @@
 import { afterAll, beforeAll, describe, expect, it } from "vitest";
-import { spawn } from "node:child_process";
+import spawn from "cross-spawn";
 import { join } from "node:path";
 import { chromium, type Browser, type Page } from "playwright";
 import { getPort, killChild, waitForServer } from "../../../../test/integration-helpers";
diff --git a/packages/vue/test/integration/vue-pages-client.test.ts b/packages/vue/test/integration/vue-pages-client.test.ts
index d0c30a7e7..8d17a53b0 100644
--- a/packages/vue/test/integration/vue-pages-client.test.ts
+++ b/packages/vue/test/integration/vue-pages-client.test.ts
@@ -1,5 +1,6 @@
 import { describe, expect, it, beforeAll, afterAll } from "vitest";
-import { execSync, spawn } from "node:child_process";
+import { execSync } from "node:child_process";
+import spawn from "cross-spawn";
 import { join } from "node:path";
 import { readFileSync, writeFileSync } from "node:fs";
 import { chromium, type Browser, type Page } from "playwright";
@@ -764,6 +765,9 @@ describe("vue-pages client (dev)", () => {
         () => document.querySelector('[data-testid="count"]')?.textContent === "Count: 1",
       );
 
+      // Wait a bit for reactive state to stabilize before HMR (Windows can be slower)
+      await new Promise((r) => setTimeout(r, 200));
+
       // Set a window marker to detect full page reload
       await page.evaluate(() => {
         (window as any).__hmr_marker = true;
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 5b2617e90..9b83c10e5 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -33,9 +33,15 @@ importers:
 
   .:
     devDependencies:
+      '@types/cross-spawn':
+        specifier: ^6.0.6
+        version: 6.0.6
       '@typescript/native-preview':
         specifier: 'catalog:'
         version: 7.0.0-dev.20260325.1
+      cross-spawn:
+        specifier: ^7.0.6
+        version: 7.0.6
       husky:
         specifier: ^9.1.7
         version: 9.1.7
@@ -3673,6 +3679,9 @@ packages:
   '@types/cookie@0.6.0':
     resolution: {integrity: sha512-4Kh9a6B2bQciAhf7FSuMRRkUWecJgJu9nPnx3yzpsfXX/c50REIqpHY4C82bXP90qrLtXtkDxTZosYO3UpOwlA==}
 
+  '@types/cross-spawn@6.0.6':
+    resolution: {integrity: sha512-fXRhhUkG4H3TQk5dBhQ7m/JDdSNHKwR2BBia62lhwEIq9xGiQKLxd6LymNhn47SjXhsUEPmxi+PKw2OkW4LLjA==}
+
   '@types/debug@4.1.13':
     resolution: {integrity: sha512-KSVgmQmzMwPlmtljOomayoR89W4FynCAi3E8PPs7vmDVPe84hT+vGPKkJfThkmXs0x0jAaa9U8uW8bbfyS2fWw==}
 
@@ -10689,6 +10698,10 @@ snapshots:
 
   '@types/cookie@0.6.0': {}
 
+  '@types/cross-spawn@6.0.6':
+    dependencies:
+      '@types/node': 25.5.0
+
   '@types/debug@4.1.13':
     dependencies:
       '@types/ms': 2.1.0
diff --git a/test/integration-helpers.ts b/test/integration-helpers.ts
index 725f33ac9..916c39eb0 100644
--- a/test/integration-helpers.ts
+++ b/test/integration-helpers.ts
@@ -1,6 +1,6 @@
 import { createServer, type Server } from "node:net";
 import { once } from "node:events";
-import type { spawn } from "node:child_process";
+import { execSync, type spawn } from "node:child_process";
 
 /**
  * Ports held by getPort() until waitForServer() releases them.
@@ -63,7 +63,18 @@ export async function waitForServer(
 
 export async function killChild(child: ReturnType<typeof spawn>): Promise<void> {
   if (child.exitCode === null && child.signalCode === null) {
-    child.kill("SIGTERM");
+    if (process.platform === "win32" && child.pid) {
+      // On Windows, SIGTERM doesn't propagate to child processes.
+      // Use taskkill /T to kill the entire process tree (e.g. workerd.exe).
+      // See: https://github.com/voidzero-dev/void/actions/runs/23939152784/job/69826006981?pr=63
+      try {
+        execSync(`taskkill /pid ${child.pid} /T /F`, { stdio: "ignore" });
+      } catch {
+        // Process may have already exited
+      }
+    } else {
+      child.kill("SIGTERM");
+    }
     await Promise.race([once(child, "exit"), new Promise((resolve) => setTimeout(resolve, 5_000))]);
     if (child.exitCode === null && child.signalCode === null) {
       child.kill("SIGKILL");