AI web agents can browse the web, click buttons, fill forms, and extract data. They can do almost anything a human can do online...except log in.

Authentication isn't a minor inconvenience; it prevents agents from completing tasks truly useful to you. Unauthenticated agents can't check your email, manage your calendar, or process a return.

Here's how to enable your agents to securely authenticate with your accounts, so they can access the services you use.

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## Cookie Syncing [Link to Cookie Syncing](/content/posts/web-agent-authentication#cookie-syncing/index.html)

When you log into a website, your browser stores cookies that prove you're authenticated. On future visits, your browser automatically sends these cookies back, so the server recognizes you without another login.

Cookie syncing copies your browser's cookie store to the agent's browser. Since the browser now has the same cookies, each website treats the agent as "you."

Most browser automation platforms support this. Browserbase calls them Contexts. Steel and Kernel call them Profiles. Internally, they're all persisting user data directories with their own cookie stores.

Here's how each platform implements it.

### Browser Use [Link to Browser Use](/content/posts/web-agent-authentication#browser-use/index.html)

Browser Use supports syncing your real Chrome profile to the cloud with a single terminal command. You can also export cookies as a file.

```python
# Sync your Chrome profile to Browser Use Cloud
# export BROWSER_USE_API_KEY=your_key && curl -fsSL https://browser-use.com/profile.sh | sh

# Or use your Chrome profile directly (OSS)
browser = Browser.from_system_chrome()

# Or export cookies for use anywhere (OSS)
await browser.export_storage_state('auth.json')
browser = Browser(storage_state='auth.json')
```

### Browserbase [Link to Browserbase](/content/posts/web-agent-authentication#browserbase/index.html)

[Browserbase](https://docs.browserbase.com/guides/authentication) persists auth state via reusable **Contexts**. The API is straightforward; you authenticate once, save the context, and load it in future sessions.

```python
context = bb.contexts.create(project_id="your_project_id")
session = bb.sessions.create(
    project_id="...",