Nuxt provides a customizable **route middleware** framework you can use throughout your application, ideal for extracting code that you want to run before navigating to a particular route.
Route middleware run within the Vue part of your Nuxt app. Despite the similar name, they are completely different from [server middleware](/docs/guide/directory-structure/server#server-middleware), which are run in the Nitro server part of your app.
Unlike [navigation guards](https://router.vuejs.org/guide/advanced/navigation-guards.html#global-before-guards) from `vue-router`, a third `next()` argument is not passed, and **redirect or route cancellation is handled by returning a value from the middleware**.
* nothing (a simple `return` or no return at all) - does not block navigation and will move to the next middleware function, if any, or complete the route navigation
*`return navigateTo('/')` - redirects to the given path and will set the redirect code to [`302` Found](https://developer.mozilla.org/en-US/docs/Web/HTTP/Status/302) if the redirect happens on the server side
*`return navigateTo('/', { redirectCode: 301 })` - redirects to the given path and will set the redirect code to [`301` Moved Permanently](https://developer.mozilla.org/en-US/docs/Web/HTTP/Status/301) if the redirect happens on the server side
*`return abortNavigation()` - stops the current navigation
*`return abortNavigation(error)` - rejects the current navigation with an error
We recommend using the helper functions above for performing redirects or stopping navigation. Other possible return values described in [the vue-router docs](https://router.vuejs.org/guide/advanced/navigation-guards.html#global-before-guards) may work but there may be breaking changes in future.
However, there may be times you want to define a specific order. For example, in the last scenario, `setup.global.ts` may need to run before `analytics.global.ts`. In that case, we recommend prefixing global middleware with 'alphabetical' numbering.
In case you're new to 'alphabetical' numbering, remember that filenames are sorted as strings, not as numeric values. For example, `10.new.global.ts` would come before `2.new.global.ts`. This is why the example prefixes single digit numbers with `0`.
If your site is server-rendered or generated, middleware for the initial page will be executed both when the page is rendered and then again on the client. This might be needed if your middleware needs a browser environment, such as if you have a generated site, aggressively cache responses, or want to read a value from local storage.
However, if you want to avoid this behaviour you can do so:
Rendering an error page is an entirely separate page load, meaning any registered middleware will run again. You can use [`useError`](/docs/getting-started/error-handling#useerror) in middleware to check if an error is being handled.
It is possible to add global or named route middleware manually using the [`addRouteMiddleware()`](/docs/api/utils/add-route-middleware) helper function, such as from within a plugin.