`EADDRINUSE` error when trying to spin up multiple TanStack Start dev servers

[AJ-505]

Which project does this relate to?

Start

Describe the bug

I was trying to start multiple dev servers and I got the following error:

node:events:486
      throw er; // Unhandled 'error' event
      ^

Error: listen EADDRINUSE: address already in use :::42069
    at Server.setupListenHandle [as _listen2] (node:net:1940:16)
    at listenInCluster (node:net:1997:12)
    at Server.listen (node:net:2102:7)
    at ServerEventBus.start ([project]/node_modules/.pnpm/@tanstack+devtools-event-bus@0.3.3/node_modules/@tanstack/devtools-event-bus/dist/esm/server/server.js:155:12)
    at BasicMinimalPluginContext.configureServer ([project]/node_modules/.pnpm/@tanstack+devtools-vite@0.3.12_vite@7.3.0_@types+node@22.19.3_jiti@2.6.1_lightningcss@1.30.2_tsx@4.21.0_/node_modules/@tanstack/devtools-vite/dist/esm/plugin.js:52:15)
    at _createServer ([project]/node_modules/.pnpm/vite@7.3.0_@types+node@22.19.3_jiti@2.6.1_lightningcss@1.30.2_tsx@4.21.0/node_modules/vite/dist/node/chunks/config.js:25602:97)
    at async CAC.<anonymous> ([project]/node_modules/.pnpm/vite@7.3.0_@types+node@22.19.3_jiti@2.6.1_lightningcss@1.30.2_tsx@4.21.0/node_modules/vite/dist/node/cli.js:572:18)
    Emitted 'error' event on Server instance at:
        at emitErrorNT (node:net:1976:8)
        at process.processTicksAndRejections (node:internal/process/task_queues:89:21) {
    code: 'EADDRINUSE',
    errno: -98,
    syscall: 'listen',
    address: '::',
    port: 42069
}

Node.js v25.2.1
 ELIFECYCLE  Command failed with exit code 1.

Your Example Website or App

https://github.com/AJ-505/serverbus-conflict-repro

Steps to Reproduce the Bug or Issue

1. Clone the reproduction repository
2. Install dependencies (pnpm install)
3. Start dev server (pnpm dev)
4. Open a new terminal tab/window, navigate to the project directory and start another server (pnpm dev again)
5. Error occurs as shown above

Expected behavior

I expect multiple TanStack Start dev servers to run seamlessly in parallel.

Screenshots or Videos

No response

Platform

• Router / Start Version: 1.132.0
• OS: Linux - Ubuntu, via the Windows subsystem for Linux (WSL)
• Browser: Google Chrome
• Browser Version: 143.0.7499.110 (Official Build) (64-bit)
• Bundler: Vite
• Bundler Version: 7.1.7

Additional context

Note:

• This conflict also occurs when trying to run dev servers for different TanStack Start projects. It does not have to be the same project.
• Also, I used pnpm here, but I've confirmed that the issue persists regardless of the package manager being used (including bun).
• Interestingly, while debugging, I noticed that the issue might be due to the devtools configuration in the vite config (from @tanstack/devtools-vite):

// vite.config.ts
const config = defineConfig({
  plugins: [
    // Commenting the next line makes the error go away
    devtools(),
    // other configs
  ]
})

I appreciate the work you guys put in at the TanStack Start team to give us great tools with a great developer experience. Thank you so much.

[coderabbitai]

📝 CodeRabbit Plan Mode

Generate an implementation plan and prompts that you can use with your favorite coding agent.

• Create Plan

Examples

• Example 1
• Example 2

---

🔗 Related PRs

TanStack/router#5284 - tests(start): update spa mode e2e to use production build [merged]
TanStack/router#5847 - docs(solid-start): start-large example [merged]
TanStack/router#5914 - example: remove undocumented vite start command [merged]

👤 Suggested Assignees

• birkskyum
• nlynzaad

---

🧪 Issue enrichment is currently in open beta.

You can configure auto-planning by selecting labels in the issue_enrichment configuration.

To disable automatic issue enrichment, add the following to your .coderabbit.yaml:

issue_enrichment:
  auto_enrich:
    enabled: false

💬 Have feedback or questions? Drop into our discord or schedule a call!

[indieTrav]

Looks like you are trying to use the same port (42069) on the same server.
Change your port. "dev": "vite dev --port 3000",

[AJ-505]

Looks like you are trying to use the same port (42069) on the same server. Change your port. "dev": "vite dev --port 3000",

My project is already configured with that "dev": .. command. I don't think it has much to do with this. (See the reproduction repo's package.json here.

[schiller-manuel]

the port is from DevTools.

[AlemTuzlak]

You can disable the event bus completely in the plugins config