First run

Try it

Needs uv; uv fetches Python itself (3.13 or newer). Runs use a Browser Use Cloud browser (BROWSER_USE_API_KEY) by default: it passes bot checks a fresh local Chrome fails. Local Chrome is fully supported with --local. A browser already running anywhere, from a container to a hosted browser with a CDP endpoint, is driven in place with --cdp-url ws://… or --cdp-port 9222: the run opens one tab and leaves the browser as it was found. To drive a window that is already open, such as an Electron app, see Open windows and Electron apps. A Node program needs neither uv nor Python: see Use it from JavaScript.

export OPENROUTER_API_KEY=...   # for Jev and the LLM that plans and reads
# export AI_GATEWAY_API_KEY=... # Vercel AI Gateway: Jev backup, and the LLM when OPENROUTER_API_KEY is unset
export BROWSER_USE_API_KEY=...  # the cloud browser; or pass --local to use Chrome
uvx fastbrowse "What is the title of the top story right now?" --start https://news.ycombinator.com/

Jev uses direct TypeSafe when TYPESAFE_API_KEY is supplied; otherwise OpenRouter is primary. Vercel AI Gateway is supported as a backup or an explicit primary. FASTBROWSE_JEV_SOURCE overrides automatic selection; see provider routing. The LLM uses OpenRouter when OPENROUTER_API_KEY is set, otherwise the Vercel AI Gateway's OpenAI-compatible chat completions.

uvx runs the published package in an isolated cached environment. uv tool install fastbrowse keeps it on your PATH, and uv add fastbrowse puts it in a project. Service keys can live in a .env file in the working directory; .env.example shows the settings. Values named by --secret must be in the process environment.

Steps go to stderr; the status, cost, step count and answer go to stdout. --json prints every step, the quotes behind the answer, and cost by component.

Flag	Effect
--start URL	the page to open first; worked out from the task when omitted
--cloud	force cloud Chrome even when FASTBROWSE_PROFILE or FASTBROWSE_HEADED is set
--local	use local Chrome instead of a Browser Use Cloud browser. Cloud is the default: it passes bot checks a fresh Chrome fails, and prints a URL to watch the run live
--headed	show the local Chrome window (implies --local)
--profile DIR	keep the local Chrome profile in DIR, so a site signed into there stays signed in (implies --local)
--cloud-profile ID	run on a Browser Use Cloud profile, signed in as whoever set it up
--cdp-url URL	drive a browser already running at this ws:// or wss:// DevTools URL instead of starting one
--cdp-port PORT	the same, for a browser or Electron app listening on 127.0.0.1:PORT; the URL is read from its /json/version
--attach	with --cdp-url or --cdp-port, drive a window already open instead of opening a tab, and leave it open after the run
--target-match TEXT	attach to the first window whose title or URL contains TEXT (implies --attach)
--proxy-country CC	browse from that country (Browser Use's codes: uk, de, ...; default us), so a shop shows its local delivery and prices
--authorize	allow submit, pay, delete and send; without it the run stops at needs_confirmation first
--secret NAME=ENV_VAR[@ORIGIN]	let the agent type $ENV_VAR on the declared origin, or the --start origin if omitted; models only see NAME. An explicit origin needs no --start
--bitwarden ITEM	match the vault login's saved URIs against --start, then allow its username, password and, when the item holds an authenticator key, one_time_code only on that start origin
--max-steps N, --max-dollars N	optionally bound steps and model spend; defaults are unlimited. Cloud browser charges are added when it stops
--downloads DIR	keep downloaded files
--json	full result instead of the answer
--record FILE	save an MP4 of the tab, each step captioned, ending on the answer, time and cost (needs ffmpeg; the captions need its libass), e.g. recordings/demo.mp4, which git ignores; demo.plain.mp4 beside it has no captions. It shows what the pages showed, so watch it before sharing
--cursor	draw the agent's cursor over a visible Chrome (--headed, or one you attach to) with Cua Driver, so you can watch where it acts. Off by default. It needs cua-driver on PATH and an X11 display on Linux, and does nothing without them

export SAUCE_PASSWORD=secret_sauce
uv run fastbrowse "Log in as standard_user with the saved password and add the backpack to the cart." \
  --start https://www.saucedemo.com/ --secret password=SAUCE_PASSWORD --authorize