CometD vs Firebase

Add the Firebase library to your app and get access to a shared data structure. Any changes made to that data are automatically synchronized with the Firebase cloud and with other clients within milliseconds.;Firebase apps can be written entirely with client-side code, update in real-time out-of-the-box, interoperate well with existing services, scale automatically, and provide strong data security.;Data Accessibility- Data is stored as JSON in Firebase. Every piece of data has its own URL which can be used in Firebase's client libraries and as a REST endpoint. These URLs can also be entered into a browser to view the data and watch it update in real-time.;Real-time Synchronization- Firebase takes a new approach to the way data is moved around an app. Rather than using a traditional request & response model, it works by synchronizing data between devices. Whenever your data changes, all clients are immediately notified within milliseconds. The synchronized data is also persisted, allowing new clients to be immediately updated.;First-class Data Security- Traditional applications intermix security code with application code, whereas Firebase treats security as a first-class feature. You define your security policies in one place using a flexible rules language, and Firebase ensures that they are consistently enforced across all parts of your application. Having all your security logic in one place allows for easy auditing and helps you avoid security mistakes. The safety and security of your data is our top priority.;Automatic Scaling- The Firebase API is built from the ground up for performance and scale. Whenever your data changes, Firebase calculates the minimum set of updates required to keep all your clients in sync. In addition, all Firebase API functions are designed to scale linearly with the size of the data being synchronized. More importantly, Firebase handles all of the scaling and operations for you. Your app will scale from its first user to its first million without any code changes.;Servers are Optional- Firebase can provide all of the data storage, control, and transmission needs of most apps. In many cases, Firebase can completely replace your server and server-side code. This means you no longer need to build complicated backend software and can instead focus on your application logic and your customers.

Javascript Client; Publish/Subscribe Messaging; Service Channels; Private Message Delivery; Lazy Messages; Message Batching; Listeners, Data Filters and Extensions; Security Policy