Web Preview
See a web app the Agent is running inside its sandbox — Buda turns its localhost link into a reachable preview URL.
When the Agent builds a website, demo, game, dashboard, or any frontend, you want to see it running. Web Preview does exactly that: the Agent starts the app inside its cloud computer, and Buda turns the sandbox localhost link into a preview URL you can open in your Local Browser.
When to use it
Use Web Preview whenever the Agent runs something that serves a port. Just ask in plain language:
Start the dev server and give me the preview link.Open the page in your Local Browser and check whether it works.Basic flow
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Ask the Agent to run the app or start a preview.
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Wait for it to output a localhost link, e.g.:
http://localhost:3000 -
Click that link in the Buda page, or open your Local Browser (not AI Browser) and enter the link in the address bar.
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Buda converts the localhost link into an external preview URL — usually one ending in
*.budaapps.com. -
Wait for that
*.budaapps.comURL to load.
The same works for any port. Enter http://localhost:4000 in your Local Browser and Buda requests a preview for port 4000.
If the preview doesn't load
If the page is blank, stuck, or errors, ask the Agent to check the process and return a fresh link:
Please use /buda-web-preview to check the process and give me a working preview link.If your Local Browser shows a WakeUp button, click it — Buda sends a restart/check request to the Agent and refreshes the preview after the service comes back.
Q&A
A *.budaapps.com URL says Unauthorized. What now?
Go back to your Local Browser and enter the original localhost URL again (e.g. http://localhost:3000). Buda requests a fresh signed preview URL and reopens it.
The preview shows Gateway Error.
The app process may not be running, or it's on a different port. Ask the Agent:
Please use /buda-web-preview to check the process and give me a preview link.You can also click WakeUp to trigger the same recovery. See the buda-web-preview skill for details on this system-managed skill.
Do I need to know the start command?
Usually no. Tell the Agent what you want — "start this project and show me the web preview" — and it inspects the project, starts the right server, and returns the link.