diff --git a/README.md b/README.md
index f91e0a4..2a71094 100644
--- a/README.md
+++ b/README.md
@@ -224,7 +224,8 @@ This eliminates the need for polling—perfect for long-running processes like b
 | Variable               | Default    | Description                                        |
 | ---------------------- | ---------- | -------------------------------------------------- |
 | `PTY_MAX_BUFFER_LINES` | `50000`    | Maximum lines to keep in output buffer per session |
-| `PTY_WEB_HOSTNAME`     | `::1`      | Hostname for the web server to bind to             |
+| `PTY_WEB_HOSTNAME`     | `::1`      | Hostname for the web server to bind to (IPv6 loopback by default) |
+| `PTY_WEB_PORT`         | `0` (random) | Port for the web server (0 = random port)        |
 
 ### Permissions
 
diff --git a/src/web/server/server.ts b/src/web/server/server.ts
index 4391751..c8e94ed 100644
--- a/src/web/server/server.ts
+++ b/src/web/server/server.ts
@@ -41,7 +41,7 @@ export class PTYServer implements Disposable {
 
   private startWebServer(): Server<undefined> {
     return Bun.serve({
-      port: 0,
+      port: process.env.PTY_WEB_PORT ? parseInt(process.env.PTY_WEB_PORT, 10) : 0,
       hostname: process.env.PTY_WEB_HOSTNAME ?? '::1',
 
       routes: {
diff --git a/test/e2e/fixtures.ts b/test/e2e/fixtures.ts
index b3dffbe..a9467ec 100644
--- a/test/e2e/fixtures.ts
+++ b/test/e2e/fixtures.ts
@@ -90,12 +90,14 @@ export const test = base.extend<TestFixtures, WorkerFixtures>({
         const serverURL = serverURLText.trim()
 
         // Parse URL to extract port number
-        const urlMatch = serverURL.match(/http:\/\/\[::1\]:(\d+)/)
+        const urlMatch = serverURL.match(/http:\/\/(?:127\.0\.0\.1|\[::1\]):(\d+)/)
         if (!urlMatch || !urlMatch[1]) {
           throw new Error(`Invalid port file format: ${serverURL}`)
         }
         const port = parseInt(urlMatch[1], 10)
-        const baseURL = `http://[::1]:${port}`
+        const baseURL = serverURL.includes('[::1]')
+          ? `http://[::1]:${port}`
+          : `http://127.0.0.1:${port}`
 
         await waitForServer(baseURL, 15000)
 
diff --git a/test/npm-pack-integration.test.ts b/test/npm-pack-integration.test.ts
index 4482506..72ce0b2 100644
--- a/test/npm-pack-integration.test.ts
+++ b/test/npm-pack-integration.test.ts
@@ -32,6 +32,7 @@ describe('npm pack integration', () => {
   let tempDir: string
   let packFile: string | null = null
   let serverProcess: ReturnType<typeof Bun.spawn> | null = null
+  let baseURL = ''
 
   afterEach(async () => {
     // Cleanup server process
@@ -137,12 +138,13 @@ describe('npm pack integration', () => {
 
     const port = await waitWithRetry()
     expect(port).not.toBe(0)
+    baseURL = `http://[::1]:${port}`
 
     // Wait for server to be ready
     let retries = 20 // 10 seconds
     while (retries > 0) {
       try {
-        const response = await fetch(`http://localhost:${port}/api/sessions`)
+        const response = await fetch(`${baseURL}/api/sessions`)
         if (response.ok) break
       } catch (error) {
         if (!(error instanceof DOMException) || error.name !== 'AbortError') {
@@ -155,12 +157,12 @@ describe('npm pack integration', () => {
     expect(retries).toBeGreaterThan(0) // Server should be ready
 
     // 5) Fetch assets
-    const assetResponse = await fetch(`http://localhost:${port}/assets/${assetName}`)
+    const assetResponse = await fetch(`${baseURL}/assets/${assetName}`)
     expect(assetResponse.status).toBe(200)
     // Could add more specific checks here, like content-type or specific assets
 
     // 6) Fetch index.html and verify it's the built version
-    const indexResponse = await fetch(`http://localhost:${port}/`)
+    const indexResponse = await fetch(`${baseURL}/`)
     expect(indexResponse.status).toBe(200)
     const indexContent = await indexResponse.text()
     expect(indexContent).not.toContain('main.tsx') // Fails if raw HTML is served