Stagehand is a software development kit for building browser agents, AI programs that operate web pages. It offers Playwright-style APIs alongside natural-language actions such as act, observe and extract. According to its makers it is built for agents rather than for testing. It is installed as a package, including for TypeScript, Python and Go, and is maintained by Browserbase.
Browserbase, Inc. is a US company in San Francisco. Stagehand itself is open source under the MIT licence and runs in your own environment, so you control the code. The associated Browserbase cloud for running browser sessions is a separate, optional service; according to its documentation sessions can be started in regions in the US, Singapore and the EU (Frankfurt), with us-west-2 as the default. That documentation does not say where session data is stored. Stagehand also sends instructions to the language model you choose, so that choice helps determine where data is processed.