Does Vitest browser mode support running the browser remotely (e.g. in Docker)?

[PaddyDrury]

Hi Vitest team

I’m experimenting with Vitest browser mode using the Playwright provider and wanted to check whether the following setup is intended to be supported.

Setup

Vitest running locally on the host

Playwright + browser running inside a Docker container

Vitest connects to Playwright via wsEndpoint

What happens

When tests start, the browser is instructed to navigate to a URL like:

http://localhost:63315/__vitest_test__/?sessionId=<UUID>

I guess this is a internal Vitest browser/orchestrator server on a random port.
Since the browser is running in Docker, localhost resolves to the container rather than the host, so navigation fails.

From what I can tell, this internal server always binds to and advertises localhost, and I haven’t found a way to configure or override it.

Question

Is Vitest browser mode designed to work only when the browser runs on the same machine/network namespace as Vitest, or is remote browser execution (e.g. Docker) expected to be supported?

Thanks for any clarification!

[AriPerkkio]

This should be possible with wsEndpoint option

import { defineConfig } from "vitest/config";
import { playwright } from "@vitest/browser-playwright";

export default defineConfig({
  test: {
    browser: {
      enabled: true,
      provider: playwright({
        connectOptions: {
          wsEndpoint: "...",
        },
      }),
    },
  },
});

• [TIP] Run Playwright Tests on unsupported Linux distributions microsoft/playwright#26482

[PaddyDrury]

I have tried this. As I said, the browser then attempts to connect to http://localhost:63315/__vitest_test__/?sessionId= which it can't because localhost resolves to 127.0.0.1 in the container.

[AriPerkkio]

Configuring those should be possible via https://vitest.dev/config/browser.html#browser-api https://vitest.dev/config/browser/api.html#browser-api.

## browser.api

- **Type:** `number | { port?, strictPort?, host? }`
- **Default:** `63315`
- **CLI:** `--browser.api=63315`, `--browser.api.port=1234, --browser.api.host=example.com`

Configure options for Vite server that serves code in the browser. Does not affect [`test.api`](#api) option. By default, Vitest assigns port `63315` to avoid conflicts with the development server, allowing you to run both in parallel.

[sheremet-va]

The correct link is https://vitest.dev/config/browser/api.html

[PaddyDrury]

Many thanks, the browser API configuration is what I needed.