> ## 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 API v4 — the current REST API for long-horizon agents.

## 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/v4
```

See [Thinking levels](/cloud/agent/thinking-levels) for V4 `modelParams`,
provider-native reasoning values, and BYOK behavior.

## The core loop

Create a run, poll its status until terminal, then fetch the full result. `status` is a cheap indexed lookup — poll it, not the full run.

```bash Create a run theme={null}
curl -X POST https://api.browser-use.com/api/v4/runs \
  -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 Poll status until completed | failed | cancelled (replace RUN_ID) theme={null}
curl https://api.browser-use.com/api/v4/runs/RUN_ID/status \
  -H "X-Browser-Use-API-Key: bu_your_key_here"
```

```bash Fetch the full run once it's terminal theme={null}
curl https://api.browser-use.com/api/v4/runs/RUN_ID \
  -H "X-Browser-Use-API-Key: bu_your_key_here"
```

## Sessions and follow-ups

A run belongs to a session (a conversation). Send a follow-up message to a session's queue — it runs as the next turn, or immediately with `interrupt: true`:

```bash Queue a follow-up (replace SESSION_ID) theme={null}
curl -X POST https://api.browser-use.com/api/v4/sessions/SESSION_ID/queue \
  -H "X-Browser-Use-API-Key: bu_your_key_here" \
  -H "Content-Type: application/json" \
  -d '{"text": "Now open the top result", "interrupt": false}'
```

## Direct browser control

Use the browser endpoints when your code will control Chrome over CDP instead of asking a hosted agent to do the work:

1. `POST /browsers` creates a browser and returns its `id` and `cdpUrl`.
2. Use `cdpUrl` with a local Browser Use agent (`Browser(cdp_url=...)`), Browser Use CLI (`BU_CDP_URL`), Playwright, Puppeteer, or Selenium.
3. `PATCH /browsers/{id}` with `{"action":"stop"}` stops the browser.

See [remote Browser Use](/open-source/customize/browser/remote), [Browser Use CLI](/open-source/browser-use-cli), or [Playwright, Puppeteer, Selenium](/cloud/browser/playwright-puppeteer-selenium) for complete connection examples.

## SDKs

The [Cloud SDK quick start](/cloud/agent/quickstart) wraps this loop — `runs.create()` then `runs.waitForCompletion()` / `runs.wait_for_completion()` — for TypeScript and Python.