# meta-refresh

The `metarefresh` challenge asks the browser to refresh the page after a delay.

The challenge uses either an HTML meta refresh or an HTTP `Refresh` header.
Both direct the browser to the challenge endpoint after `difficulty + 1` seconds.
The server requires at least 800 milliseconds per unit of `difficulty` before it accepts the response.

## Configuration

Add a browser rule to the `bots` list:

```yaml
bots:
  - name: generic-browser
    expression: userAgent.matches("Mozilla|Opera")
    action: CHALLENGE
    challenge:
      algorithm: metarefresh
      difficulty: 1
```

With `difficulty: 1`, the browser refreshes after two seconds.
The expression matches a User-Agent that contains `Mozilla` or `Opera`.
See [policies](/docs/policies.md) for rule order and actions.
See [expressions](/docs/configuration/expressions.md) for other match conditions.