# Cloud browser (/docs/use-cases/remote-browser)
Related: [Coding Agents](/docs/use-cases/coding-agents.md), [Computer use](/docs/use-cases/computer-use.md), [GitHub Actions CI/CD](/docs/use-cases/ci-cd.md), [Run Kubernetes with k3s](/docs/use-cases/k3s.md), [Amp](/docs/agents/amp.md)
This guide covers **cloud browsers** powered by [Kernel](https://www.kernel.sh/) — cloud Chromium instances your code controls via [CDP](https://chromedevtools.github.io/devtools-protocol/) or the [Kernel SDK](https://www.kernel.sh/docs/sdk/overview). For **local browser automation** using a virtual desktop, see [Computer use](/docs/use-cases/computer-use).
Cloud browsers run on Kernel's managed infrastructure, not inside your sandbox. This gives you sub-second browser startup, [persistent sessions you can pause and resume](https://www.onkernel.com/docs/browsers/persistence) across hours or days, and reusable browser state. Your agent connects to them over the network via CDP, BiDi, or their CUA API.
Kernel handles CAPTCHA solving, residential proxies, authentication, and observability out of the box.
## Prerequisites [#prerequisites]
* An [E2B API key](https://e2b.dev/dashboard?tab=keys)
* A [Kernel API key](https://dashboard.onkernel.com/api-keys)
* Python 3.10+ / Node.js 18+
JavaScript & TypeScript
Python
```bash
npm i e2b @onkernel/sdk playwright-core
```
```bash
pip install e2b kernel playwright
```
Set your keys in the environment:
```bash title=".env"
E2B_API_KEY=e2b_***
KERNEL_API_KEY=kernel_***
```
E2B provides a pre-built sandbox template with the Kernel SDK and Playwright already installed:
| Template | What's included | Best for |
| ---------------- | ----------------------------------- | ------------------------------------------------------ |
| `kernel-browser` | Kernel SDK, Playwright, Browser Use | Screenshots, scraping, app previews, autonomous agents |
## Examples [#examples]
Here are three common patterns for using cloud browsers with E2B sandboxes.
Deploy a web app in a sandbox, screenshot every route
Let an LLM autonomously browse and extract data
Watch the browser in real time via Kernel's live view
***
## Screenshot app endpoints [#screenshot-app-endpoints]
Deploy a web app inside an E2B sandbox, get a public URL, then use a Kernel cloud browser to screenshot every route.
JavaScript & TypeScript
Python
```typescript
import { Sandbox } from 'e2b'
// A minimal FastAPI app with three routes to screenshot
const FASTAPI_APP = `
from fastapi import FastAPI
from fastapi.responses import HTMLResponse
app = FastAPI()
@app.get("/")
def home():
return HTMLResponse("Home
Welcome to the app.
")
@app.get("/about")
def about():
return HTMLResponse("About
About this app.
")
@app.get("/dashboard")
def dashboard():
return HTMLResponse("Dashboard
Your dashboard.
")
`
const sandbox = await Sandbox.create('kernel-browser', {
envs: { KERNEL_API_KEY: process.env.KERNEL_API_KEY! },
timeoutMs: 300_000,
})
await sandbox.files.write('/home/user/app.py', FASTAPI_APP)
await sandbox.commands.run(
'pip install fastapi uvicorn',
{ timeoutMs: 60_000 },
)
await sandbox.commands.run(
'uvicorn app:app --host 0.0.0.0 --port 8000',
{ background: true, cwd: '/home/user' },
)
```
```python
import os
from e2b import Sandbox
# A minimal FastAPI app with three routes to screenshot
FASTAPI_APP = """
from fastapi import FastAPI
from fastapi.responses import HTMLResponse
app = FastAPI()
@app.get("/")
def home():
return HTMLResponse("Home
Welcome to the app.
")
@app.get("/about")
def about():
return HTMLResponse("About
About this app.
")
@app.get("/dashboard")
def dashboard():
return HTMLResponse("Dashboard
Your dashboard.
")
"""
sandbox = Sandbox.create(
"kernel-browser",
envs={"KERNEL_API_KEY": os.environ["KERNEL_API_KEY"]},
timeout=300,
)
sandbox.files.write("/home/user/app.py", FASTAPI_APP)
sandbox.commands.run(
"pip install fastapi uvicorn",
timeout=60,
)
sandbox.commands.run(
"uvicorn app:app --host 0.0.0.0 --port 8000",
background=True,
cwd="/home/user",
)
```
E2B exposes any sandbox port as a public HTTPS endpoint. Write a browsing script into the sandbox that creates a Kernel browser and screenshots each route.
JavaScript & TypeScript
Python
```typescript
const host = sandbox.getHost(8000)
const appUrl = `https://${host}`
const BROWSE_SCRIPT = `
import sys
from kernel import Kernel
from playwright.sync_api import sync_playwright
app_url = "${appUrl}"
routes = ["/", "/about", "/dashboard"]
kernel = Kernel()
kb = kernel.browsers.create()
with sync_playwright() as pw:
browser = pw.chromium.connect_over_cdp(kb.cdp_ws_url)
page = browser.new_page()
page.set_viewport_size({"width": 1280, "height": 720})
for route in routes:
page.goto(f"{app_url}{route}", wait_until="networkidle")
name = "home" if route == "/" else route.strip("/")
page.screenshot(path=f"/home/user/{name}.png")
print(f"Captured {route}")
browser.close()
`
await sandbox.files.write('/home/user/browse.py', BROWSE_SCRIPT)
const result = await sandbox.commands.run(
'python3 /home/user/browse.py',
{ timeoutMs: 60_000 },
)
console.log(result.stdout)
await sandbox.kill()
```
```python
host = sandbox.get_host(8000)
app_url = f"https://{host}"
BROWSE_SCRIPT = f'''
from kernel import Kernel
from playwright.sync_api import sync_playwright
app_url = "{app_url}"
routes = ["/", "/about", "/dashboard"]
kernel = Kernel()
kb = kernel.browsers.create()
with sync_playwright() as pw:
browser = pw.chromium.connect_over_cdp(kb.cdp_ws_url)
page = browser.new_page()
page.set_viewport_size({{"width": 1280, "height": 720}})
for route in routes:
page.goto(f"{{app_url}}{{route}}", wait_until="networkidle")
name = "home" if route == "/" else route.strip("/")
page.screenshot(path=f"/home/user/{{name}}.png")
print(f"Captured {{route}}")
browser.close()
'''
sandbox.files.write("/home/user/browse.py", BROWSE_SCRIPT)
result = sandbox.commands.run("python3 /home/user/browse.py", timeout=60)
print(result.stdout)
sandbox.kill()
```
Full example:
JavaScript & TypeScript
Python
```typescript expandable
import { Sandbox } from 'e2b'
// A minimal FastAPI app with three routes to screenshot
const FASTAPI_APP = `
from fastapi import FastAPI
from fastapi.responses import HTMLResponse
app = FastAPI()
@app.get("/")
def home():
return HTMLResponse("Home
Welcome to the app.
")
@app.get("/about")
def about():
return HTMLResponse("About
About this app.
")
@app.get("/dashboard")
def dashboard():
return HTMLResponse("Dashboard
Your dashboard.
")
`
// 1. Create the sandbox and start the app
const sandbox = await Sandbox.create('kernel-browser', {
envs: { KERNEL_API_KEY: process.env.KERNEL_API_KEY! },
timeoutMs: 300_000,
})
await sandbox.files.write('/home/user/app.py', FASTAPI_APP)
await sandbox.commands.run(
'pip install fastapi uvicorn',
{ timeoutMs: 60_000 },
)
await sandbox.commands.run(
'uvicorn app:app --host 0.0.0.0 --port 8000',
{ background: true, cwd: '/home/user' },
)
// 2. Screenshot each route with a Kernel browser
const host = sandbox.getHost(8000)
const appUrl = `https://${host}`
const BROWSE_SCRIPT = `
import sys
from kernel import Kernel
from playwright.sync_api import sync_playwright
app_url = "${appUrl}"
routes = ["/", "/about", "/dashboard"]
kernel = Kernel()
kb = kernel.browsers.create()
with sync_playwright() as pw:
browser = pw.chromium.connect_over_cdp(kb.cdp_ws_url)
page = browser.new_page()
page.set_viewport_size({"width": 1280, "height": 720})
for route in routes:
page.goto(f"{app_url}{route}", wait_until="networkidle")
name = "home" if route == "/" else route.strip("/")
page.screenshot(path=f"/home/user/{name}.png")
print(f"Captured {route}")
browser.close()
`
await sandbox.files.write('/home/user/browse.py', BROWSE_SCRIPT)
const result = await sandbox.commands.run(
'python3 /home/user/browse.py',
{ timeoutMs: 60_000 },
)
console.log(result.stdout)
await sandbox.kill()
```
```python expandable
import os
from e2b import Sandbox
# A minimal FastAPI app with three routes to screenshot
FASTAPI_APP = """
from fastapi import FastAPI
from fastapi.responses import HTMLResponse
app = FastAPI()
@app.get("/")
def home():
return HTMLResponse("Home
Welcome to the app.
")
@app.get("/about")
def about():
return HTMLResponse("About
About this app.
")
@app.get("/dashboard")
def dashboard():
return HTMLResponse("Dashboard
Your dashboard.
")
"""
# 1. Create the sandbox and start the app
sandbox = Sandbox.create(
"kernel-browser",
envs={"KERNEL_API_KEY": os.environ["KERNEL_API_KEY"]},
timeout=300,
)
sandbox.files.write("/home/user/app.py", FASTAPI_APP)
sandbox.commands.run(
"pip install fastapi uvicorn",
timeout=60,
)
sandbox.commands.run(
"uvicorn app:app --host 0.0.0.0 --port 8000",
background=True,
cwd="/home/user",
)
# 2. Screenshot each route with a Kernel browser
host = sandbox.get_host(8000)
app_url = f"https://{host}"
BROWSE_SCRIPT = f'''
from kernel import Kernel
from playwright.sync_api import sync_playwright
app_url = "{app_url}"
routes = ["/", "/about", "/dashboard"]
kernel = Kernel()
kb = kernel.browsers.create()
with sync_playwright() as pw:
browser = pw.chromium.connect_over_cdp(kb.cdp_ws_url)
page = browser.new_page()
page.set_viewport_size({{"width": 1280, "height": 720}})
for route in routes:
page.goto(f"{{app_url}}{{route}}", wait_until="networkidle")
name = "home" if route == "/" else route.strip("/")
page.screenshot(path=f"/home/user/{{name}}.png")
print(f"Captured {{route}}")
browser.close()
'''
sandbox.files.write("/home/user/browse.py", BROWSE_SCRIPT)
result = sandbox.commands.run("python3 /home/user/browse.py", timeout=60)
print(result.stdout)
sandbox.kill()
```
***
## Agent data extraction [#agent-data-extraction]
Use [Browser Use](https://docs.browser-use.com/) to let an LLM autonomously browse a website and extract data. The agent sees the page via screenshots and decides what to click, type, and navigate.
This requires an additional LLM API key:
```bash title=".env"
ANTHROPIC_API_KEY=sk-ant-***
```
JavaScript & TypeScript
Python
```typescript
import { Sandbox } from 'e2b'
const sandbox = await Sandbox.create('kernel-browser', {
envs: {
KERNEL_API_KEY: process.env.KERNEL_API_KEY!,
ANTHROPIC_API_KEY: process.env.ANTHROPIC_API_KEY!,
},
timeoutMs: 300_000,
})
```
```python
import os
from e2b import Sandbox
sandbox = Sandbox.create(
"kernel-browser",
envs={
"KERNEL_API_KEY": os.environ["KERNEL_API_KEY"],
"ANTHROPIC_API_KEY": os.environ["ANTHROPIC_API_KEY"],
},
timeout=300,
)
```
The agent script runs inside the sandbox. Browser Use and its dependencies come pre-installed in the `kernel-browser` template. The script creates a Kernel browser, connects Browser Use, and completes the task autonomously.
JavaScript & TypeScript
Python
```typescript
const AGENT_SCRIPT = `
import asyncio
from kernel import Kernel
from browser_use import Agent, Browser, ChatAnthropic
async def main():
kernel = Kernel()
kb = kernel.browsers.create()
browser = Browser(cdp_url=kb.cdp_ws_url)
agent = Agent(
task="Go to https://news.ycombinator.com, find the top 5 stories, and return their titles and point counts as JSON",
llm=ChatAnthropic(model="claude-sonnet-4"),
browser=browser,
)
result = await agent.run()
print(result)
asyncio.run(main())
`
await sandbox.files.write('/home/user/agent_task.py', AGENT_SCRIPT)
const result = await sandbox.commands.run(
'python3 /home/user/agent_task.py',
{ timeoutMs: 180_000 },
)
console.log(result.stdout)
await sandbox.kill()
```
```python
AGENT_SCRIPT = '''
import asyncio
from kernel import Kernel
from browser_use import Agent, Browser, ChatAnthropic
async def main():
kernel = Kernel()
kb = kernel.browsers.create()
browser = Browser(cdp_url=kb.cdp_ws_url)
agent = Agent(
task="Go to https://news.ycombinator.com, find the top 5 stories, and return their titles and point counts as JSON",
llm=ChatAnthropic(model="claude-sonnet-4"),
browser=browser,
)
result = await agent.run()
print(result)
asyncio.run(main())
'''
sandbox.files.write("/home/user/agent_task.py", AGENT_SCRIPT)
result = sandbox.commands.run("python3 /home/user/agent_task.py", timeout=180)
print(result.stdout)
sandbox.kill()
```
Full example:
JavaScript & TypeScript
Python
```typescript expandable
import { Sandbox } from 'e2b'
// 1. Create the sandbox with API keys
const sandbox = await Sandbox.create('kernel-browser', {
envs: {
KERNEL_API_KEY: process.env.KERNEL_API_KEY!,
ANTHROPIC_API_KEY: process.env.ANTHROPIC_API_KEY!,
},
timeoutMs: 300_000,
})
// 2. Write and run the Browser Use agent
const AGENT_SCRIPT = `
import asyncio
from kernel import Kernel
from browser_use import Agent, Browser, ChatAnthropic
async def main():
kernel = Kernel()
kb = kernel.browsers.create()
browser = Browser(cdp_url=kb.cdp_ws_url)
agent = Agent(
task="Go to https://news.ycombinator.com, find the top 5 stories, and return their titles and point counts as JSON",
llm=ChatAnthropic(model="claude-sonnet-4"),
browser=browser,
)
result = await agent.run()
print(result)
asyncio.run(main())
`
await sandbox.files.write('/home/user/agent_task.py', AGENT_SCRIPT)
const result = await sandbox.commands.run(
'python3 /home/user/agent_task.py',
{ timeoutMs: 180_000 },
)
console.log(result.stdout)
await sandbox.kill()
```
```python expandable
import os
from e2b import Sandbox
# 1. Create the sandbox with API keys
sandbox = Sandbox.create(
"kernel-browser",
envs={
"KERNEL_API_KEY": os.environ["KERNEL_API_KEY"],
"ANTHROPIC_API_KEY": os.environ["ANTHROPIC_API_KEY"],
},
timeout=300,
)
# 2. Write and run the Browser Use agent
AGENT_SCRIPT = '''
import asyncio
from kernel import Kernel
from browser_use import Agent, Browser, ChatAnthropic
async def main():
kernel = Kernel()
kb = kernel.browsers.create()
browser = Browser(cdp_url=kb.cdp_ws_url)
agent = Agent(
task="Go to https://news.ycombinator.com, find the top 5 stories, and return their titles and point counts as JSON",
llm=ChatAnthropic(model="claude-sonnet-4"),
browser=browser,
)
result = await agent.run()
print(result)
asyncio.run(main())
'''
sandbox.files.write("/home/user/agent_task.py", AGENT_SCRIPT)
result = sandbox.commands.run("python3 /home/user/agent_task.py", timeout=180)
print(result.stdout)
sandbox.kill()
```
***
## Live browser preview [#live-browser-preview]
Kernel provides a live view URL for every browser session — you can watch the browser in real time or embed it in your app. This is useful for debugging, demos, or letting users see what the agent is doing.
JavaScript & TypeScript
Python
```typescript
import { Sandbox } from 'e2b'
const sandbox = await Sandbox.create('kernel-browser', {
envs: { KERNEL_API_KEY: process.env.KERNEL_API_KEY! },
timeoutMs: 300_000,
})
const LIVE_VIEW_SCRIPT = `
from kernel import Kernel
kernel = Kernel()
browser = kernel.browsers.create()
# Print the live view URL — accessible from any browser
print(browser.browser_live_view_url)
`
await sandbox.files.write('/home/user/live_view.py', LIVE_VIEW_SCRIPT)
const result = await sandbox.commands.run(
'python3 /home/user/live_view.py',
{ timeoutMs: 30_000 },
)
const liveViewUrl = result.stdout.trim()
console.log('Watch the browser:', liveViewUrl)
// Embed in your app as an iframe
//
// Read-only mode (no mouse/keyboard interaction)
// liveViewUrl + '?readOnly=true'
```
```python
import os
from e2b import Sandbox
sandbox = Sandbox.create(
"kernel-browser",
envs={"KERNEL_API_KEY": os.environ["KERNEL_API_KEY"]},
timeout=300,
)
LIVE_VIEW_SCRIPT = '''
from kernel import Kernel
kernel = Kernel()
browser = kernel.browsers.create()
# Print the live view URL — accessible from any browser
print(browser.browser_live_view_url)
'''
sandbox.files.write("/home/user/live_view.py", LIVE_VIEW_SCRIPT)
result = sandbox.commands.run("python3 /home/user/live_view.py", timeout=30)
live_view_url = result.stdout.strip()
print("Watch the browser:", live_view_url)
# Embed in your app as an iframe
#
# Read-only mode (no mouse/keyboard interaction)
# live_view_url + '?readOnly=true'
```
The live view URL stays active until the browser is deleted or times out. For more details, see the [Kernel live view documentation](https://www.kernel.sh/docs/browsers/live-view).
## Related guides [#related-guides]
Local browser automation with virtual desktops
Create, manage, and control sandbox lifecycle
Run terminal commands inside the sandbox