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# Custom Koa Server example## How to useDownload the example [or clone the repo](https://github.com/zeit/next.js):```bashcurl https://codeload.github.com/zeit/next.js/tar.gz/master | tar-xz--strip=2 next.js-master/examples/custom-server-koacd custom-server-koa```Install it and run:```bashnpm installnpm run dev```Deploy it to the cloud with [now](https://zeit.co/now)([download](https://zeit.co/download))```bashnow```## The idea behind the exampleMost of the times the default Next server will be enough but sometimes you want to run your own server to customize routes or other kind of the app behavior. Next provides a [Custom server and routing](https://github.com/zeit/next.js#custom-server-and-routing) so you can customize as much as you want.Because the Next.js server is just a node.js module you can combine it with any other part of the node.js ecosystem. in this case we are using [Koa](http://koajs.com/) to build a custom router on top of Next.The example shows a server that serves the component living in `pages/a.js` when the route `/b` is requested and `pages/b.js` when the route `/a` is accessed. This is obviously a non-standard routing strategy. You can see how this custom routing is being made inside `server.js`.