# Previews

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## <a id="previews"></a>Previews

While working, the agent can stand up a live preview of a static site the Task changes, on your cloud, and check that it loads. The pull request lists each preview's URL so a reviewer can open it.

How the preview is built depends on the site:

- **A static site Deployment.io deploys** — Deployment.io builds the preview from the agent's work the same way the deployment builds it, using its build command, root directory and publish directory.
- **Another repository** — Deployment.io detects how to build it and builds it the same way. It recognises Vite, Create React App, Vue CLI, Astro, Gatsby, SvelteKit with its static adapter, and Next.js with static export. When it can't tell how, the agent builds the site itself.

A preview is removed after a period without use, and when its Task is deleted.

### <a id="preview-configuration"></a>Preview configuration

Previews Deployment.io builds use your organization's **Preview configuration**: variables and secret files set in **Org Settings → Agents → QA**.

A preview runs a Task's code before anyone has reviewed it, so add only values meant for previews — test-mode keys, sandbox endpoints and the public settings the build needs. Never add staging or production secrets.

Stored values are never shown again; to change one, enter a new value. The agent never sees these values.

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Source: https://deployment.io/docs/tasks/previews/