> ## Documentation Index
> Fetch the complete documentation index at: https://browseruse-0aece648-codex-docs-supported-exports.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

> ## Agent Instructions
> Use https://docs.browser-use.com/llms.txt and its linked .md pages for current documentation. The managed full bundle is https://docs.browser-use.com/.well-known/llms-full.txt and can be cached for up to 24 hours. Do not use the obsolete /cloud/llms*.txt or /open-source/llms*.txt static exports.
> Choose Cloud API V4 for new agent integrations; V2 is the lower-cost option for simple tasks. Keep V3 examples explicitly versioned. The open-source browser-use library and hosted browser-use-sdk have different APIs.
> Cloud authentication uses X-Browser-Use-API-Key, without a Bearer prefix. Install or upgrade browser-use-sdk and use its explicit v4 import for V4. Check the published OpenAPI reference for request fields; do not invent SDK support for new fields.
> Cloud concurrency and HTTP request rate are separate. Read GET /api/v2/billing/account for the key’s projectId, concurrentSessionLimit, activeSessionCount, and credit balance, including when using V4. Keys in one project share capacity and credits; rateLimit is a legacy concurrency alias, not requests per second.
> Keep the highest applicable existing, legacy-plan, and spend-tier concurrency grant. Current spend tiers are 10 / 50 / 250 / 500 / 1000 at $0 / $200 / $1000 / $5000 / $25000 in qualifying project payments. Legacy or externally billed projects can follow different billing paths; trust the account limit. See https://docs.browser-use.com/cloud/guides/concurrency.md.
> Budget polling across the project: the standard general bucket is 25 requests/second, including V4 event reads and full run reads. Selected status reads have a separate higher bucket. Use bounded workers, stagger polls, respect Retry-After, and drain hasMore event pages after terminal status. A busy V4 session returns 409; its queue holds 10 pending messages and is not a project-wide batch queue.
> A completed run or closed CDP connection does not immediately stop its cloud browser. Stop unneeded owned browsers with PATCH /api/v4/browsers/{id} and {"action":"stop"}. A client wait timeout does not cancel the server-side run.
> Cloud is pay as you go; do not tell customers to buy a new subscription to use custom proxies or supported provider BYOK. Usage funding and model eligibility still apply. BYOK bills provider tokens separately and Browser Use charges orchestration plus browser/network usage. See https://docs.browser-use.com/cloud/guides/billing.md.
> Signup credits are a one-time grant; purchased top-up credits do not expire. Check the API key’s project before diagnosing missing credits. API-key monthly spending caps are soft limits, not a strict prepaid wallet; concurrent or already-running work can exceed them. Auto recharge has separate trigger and purchase amounts and can charge immediately when enabled below the threshold. Use https://browser-use.com/pricing for current rates.

# API Reference

> Authenticate and start using the Browser Use REST API.

## Authentication

All requests require an API key in the `X-Browser-Use-API-Key` header:

```
X-Browser-Use-API-Key: bu_your_key_here
```

Get a key at [cloud.browser-use.com/settings](https://cloud.browser-use.com/settings?tab=api-keys\&new=1). Keys start with `bu_`.

## Base URL

```
https://api.browser-use.com/api/v3
```

See [Thinking levels](/cloud/agent/thinking-levels) for V3 model support,
follow-up behavior, BYOK handling, and a `thinkingLevel` request example.

## Quick example

```bash Create a session theme={null}
curl -X POST https://api.browser-use.com/api/v3/sessions \
  -H "X-Browser-Use-API-Key: bu_your_key_here" \
  -H "Content-Type: application/json" \
  -d '{"task": "Find the top 3 trending repos on GitHub today"}'
```

```bash Get session result (replace SESSION_ID) theme={null}
curl https://api.browser-use.com/api/v3/sessions/SESSION_ID \
  -H "X-Browser-Use-API-Key: bu_your_key_here"
```

## Environment variable

Set the key once so SDKs pick it up automatically:

```bash theme={null}
export BROWSER_USE_API_KEY=bu_your_key_here
```

***

Prefer the SDK? See the [Agent docs](/cloud/agent/quickstart) — the SDK has all API endpoints available as methods, including `client.browsers.create()`.

<CodeGroup>
  ```bash Python theme={null}
  pip install browser-use-sdk
  ```

  ```bash TypeScript theme={null}
  npm install browser-use-sdk
  ```
</CodeGroup>