# file_service [](https://pub.dartlang.org/packages/angel_file_service) [](https://travis-ci.org/angel-dart/file_service) Angel service that persists data to a file on disk, stored as a JSON list. It uses a simple mutex to prevent race conditions, and caches contents in memory until changes are made. The file will be created on read/write, if it does not already exist. This package is useful in development, as it prevents you from having to install an external database to run your server. When running a multi-threaded server, there is no guarantee that file operations will be mutually excluded. Thus, try to only use this one a single-threaded server if possible, or one with very low load. While not necessarily *slow*, this package makes no promises about performance. # Usage ```dart configureServer(Angel app) async { // Just like a normal service app.use( '/api/todos', new JsonFileService( const LocalFileSystem().file('todos_db.json') ), ); } ```