fortress
open source browser for ai agents
that websites don't block
100k+ installs, used by engineers at 170+ companies
sites read your graphics card, screen, fonts and timezone to decide if you're a bot. fortress makes each one match a real computer, inside chromium's c++.
each value a page reads comes from the browser, with no script layer to detect.
cursor paths taken from about 10,000 recorded people.
the same fingerprint either way, on datacenter ips.
v3 runs chromium 153 and moves up every month.
change the line that launches the browser so it connects to fortress on localhost:9222. the rest of the script stays as it is.
python and javascript, over the chrome devtools protocol.
browser-use, crawl4ai, stagehand and langchain.
docker, pip, npm, a .deb or a single binary.
native builds for each, plus arm64 linux.
claude, codex, cursor, windsurf and cline can call 29 fortress tools. when a plain fetch gets a 403, the agent opens the page with fortress instead.
returns the page as clean text the agent can use.
turns a page into the fields the agent asked for.
logs in, pages through results and fills in forms.
the tools run on your machine, with no account.
each session gets its own graphics card, screen size, timezone and language, picked to agree with each other, so a hundred sessions don't look like one bot.
canvas and audio fingerprints differed on every one of 40 launches.
timezone, language and fonts follow the country you set.
change the whole identity from a saved snapshot.
no caps on machines, sessions or concurrency.
we sent eight browsers to 92 websites that block bots, twice each, from a server with no proxies. fortress got the page more often than any of them.
behind cloudflare, datadome, akamai, perimeterx, kasada and more.
one machine per visit, on datacenter ips, no proxies, no captcha solver.
camoufox loaded 74.5%, the chrome-based stealth tools 34 to 72%.
the sites, the method and the harness are in the repo.
plan and price trips across airline and hotel sites.
find the cheapest nonstop from sfo to jfk next friday
compare tonight's rates at five hotels near shibuya
check the fare every morning and flag it when it drops under $300
book the best-rated room under $250 and save the confirmation