Playwright E2E Test

Deploy a Playwright sandbox to Blaxel dev, wait for it to be ready, connect via Playwright, and run browser tests.

Supported sandbox templates:

• playwright-chromium -- Chromium browser, connect via chromium.connect()
• playwright-firefox -- Firefox browser, connect via firefox.connect()

Both expose the same Playwright server on port 8081 with the same protocol. The only difference is the browser type used to connect.

Prerequisites

• bl CLI authenticated on the target workspace (bl login)
• node available locally
• playwright npm package installed locally (matching the server version)

Step 1: Pick the sandbox template

Determine which browser to test. Use SANDBOX_NAME=playwright-chromium or SANDBOX_NAME=playwright-firefox. If the user doesn't specify, default to playwright-chromium. If both need testing, run the steps below once per browser.

Step 2: Build and push the image

Use bl push to build and push the image without creating the sandbox resource:

bl push -y -t sandbox -d hub/$SANDBOX_NAME -n $SANDBOX_NAME

This builds the image from hub/$SANDBOX_NAME/Dockerfile and pushes it to the Blaxel registry.

Note: The CLI may report build timed out after 15 minutes for large images (~1.9 GB). If the logs show ✅ Build completed successfully before the timeout, the image was pushed successfully and you can proceed. The timeout is a CLI-side log monitoring limit, not a server-side failure.

Step 3: Create the sandbox with port config

Use bl apply to create the sandbox resource with the correct port declarations. Port 8081 (Playwright server) must be declared, otherwise only port 8080 (sandbox-api) is exposed and Playwright connections fail with 502.

bl apply -f - <<EOF
apiVersion: blaxel.ai/v1alpha1
kind: Sandbox
metadata:
  name: $SANDBOX_NAME
spec:
  runtime:
    image: sandbox/$SANDBOX_NAME:latest
    memory: 4096
    ports:
      - name: sandbox-api
        target: 8080
        protocol: HTTP
      - name: playwright
        target: 8081
        protocol: HTTP
EOF

Step 4: Wait for the sandbox to be ready

Poll until the sandbox status is DEPLOYED. Note: bl get sbx returns a JSON array, so access [0].

while true; do
  STATUS=$(bl get sbx $SANDBOX_NAME -ojson 2>/dev/null | jq -r '.[0].status')
  echo "Sandbox status: $STATUS"
  if [ "$STATUS" = "DEPLOYED" ]; then
    break
  fi
  sleep 5
done

Step 5: Retrieve the sandbox URL and wait for Playwright server

SANDBOX_URL=$(bl get sbx $SANDBOX_NAME -ojson | jq -r '.[0].metadata.url')

The DEPLOYED status means the image is pushed, but the VM may still be cold-starting. Poll the Playwright server until it responds:

TOKEN=$(bl token)
while true; do
  HTTP_STATUS=$(curl -s -o /dev/null -w "%{http_code}" -H "Authorization: Bearer $TOKEN" "$SANDBOX_URL/port/8081/json" 2>/dev/null)
  echo "Playwright server HTTP status: $HTTP_STATUS"
  if [ "$HTTP_STATUS" = "200" ]; then
    break
  fi
  sleep 10
done

Step 6: Run the Playwright test

Connect with the token as a ?token= query parameter on the WebSocket URL.

Use the browser type matching the sandbox:

• playwright-chromium --> chromium.connect()
• playwright-firefox --> firefox.connect()

Write a Node.js script that:

1. Connects to wss://{SANDBOX_HOST}/port/8081/?token={TOKEN} using the appropriate browser type
2. Creates a new page
3. Navigates to a test URL (e.g. https://example.com)
4. Asserts the page loaded correctly (title, DOM elements)
5. Closes the browser

Chromium example

const { chromium } = require('playwright');

const browser = await chromium.connect(
  `wss://${SANDBOX_HOST}/port/8081/?token=${TOKEN}`,
  { timeout: 15000 }
);

const page = await browser.newPage();
await page.goto('https://example.com');
const title = await page.title();
assert(title.includes('Example Domain'));

await page.close();
await browser.close();

Firefox example

const { firefox } = require('playwright');

const browser = await firefox.connect(
  `wss://${SANDBOX_HOST}/port/8081/?token=${TOKEN}`,
  { timeout: 15000 }
);

const page = await browser.newPage();
await page.goto('https://example.com');
const title = await page.title();
assert(title.includes('Example Domain'));

await page.close();
await browser.close();

Important notes

• Version match: The local playwright package version MUST match the server version. The sandbox runs Playwright v1.58. If you get a 428 Precondition Required with a version mismatch error, install the correct version: npm install playwright@1.58.
• Connection method: Use browserType.connect(), NOT connectOverCDP(). The sandbox runs a Playwright server, not a raw CDP endpoint.
• Browser type: Must match the sandbox template. chromium.connect() for playwright-chromium, firefox.connect() for playwright-firefox. Using the wrong browser type will fail.
• Auth: Pass the JWT token as ?token= query parameter on the WebSocket URL.
• Ports: Port 8080 is the sandbox-api, port 8081 is the Playwright server. Both must be declared in the bl apply spec.

Step 7: Cleanup

After tests pass, optionally delete the sandbox:

bl delete sbx $SANDBOX_NAME

Troubleshooting

• 401 Unauthorized: Token expired or wrong workspace. Run bl token to refresh.
• 428 Precondition Required: Playwright version mismatch between client and server. Check the error message for the server version and install the matching client.
• 502 Bad Gateway on port 8081: Either the Playwright server hasn't started yet (wait longer), or port 8081 was not declared in the bl apply spec. Check with bl get sbx $SANDBOX_NAME -ojson | jq '.[0].spec.runtime.ports'.
• Sandbox stuck in DEPLOYING: Check bl logs sbx $SANDBOX_NAME for build errors.