Live preview

The preview is your app, running for real in an isolated sandbox, on a URL only you can open.

Starting

Click Run preview (or send a prompt — the preview starts automatically the first time). The first start:

1. Prepare — provisions the database if needed and writes .env.
2. Install — installs dependencies. The template's dependencies are pre-installed in the sandbox image, so this is fast unless you've added packages.
3. Start — launches the Next.js dev server.
4. Live — the first page has compiled and answered.

Typically under a minute; the progress panel shows the current step and how long it has taken. If a step fails, the panel shows why and offers Try again.

The URL

https://preview--<slug>.apps.qyant.dev — shown in the preview header and under Open (opens in a new tab). The preview is private: it answers only to the signed-in project owner. Anyone else gets a sign-in prompt. This is deliberate; to share a running app, deploy it.

Updating

• Accepting a change or saving a file pushes the files into the sandbox; Next's hot reload picks them up in a few seconds.
• Changing .env or package.json needs a restart (Stop → Run preview) so the process sees the new values or installs the new package.

Errors in your app

Because the preview runs the real dev server, runtime errors show Next.js's error overlay with the stack trace — the same thing you'd see locally. Paste the message into the chat and ask for the fix.

Stopping

Previews stop automatically after 30 minutes without activity to free resources, and you can stop one any time with Stop preview. Starting again is faster than the first time. Your files and database are unaffected by stops.

Resources

Each sandbox has 1 vCPU, 2 GB of memory and a process limit. That's comfortable for a Next.js dev server; if you're doing something unusual (video processing, large in-memory datasets) it's the first thing to check when something is slow.

Concurrency

The number of previews you can have running at once depends on your plan — see Limits.