While [Cloud Storage](https://docs.cloud.google.com/appengine/docs/standard/using-cloud-storage) is the recommended solution for reading and writing files in App Engine, if your app only needs to write temporary files, you can use language-specific methods to write files to a directory named `/tmp`. All files in this directory are stored in the instance's RAM, therefore writing to `/tmp` takes up system memory. In addition, files in the `/tmp` directory are only available to the app instance that created the files. When the instance is deleted, the temporary files are deleted.