When comparing Back4App vs Kuzzle, the Slant community recommends Kuzzle for most people. In the question“What are the best Backend as a Service providers for webapps?” Kuzzle is ranked 4th while Back4App is ranked 5th. The most important reason people chose Kuzzle is:
Ranked in these QuestionsQuestion Ranking
Pro Open source
Back4app is an open source BAAS and Backend generator.
Pro Smooth migration from Parse
Back4App offers a smooth migration for all former Parse users who wish to migrate their data now that Parse has announced that it will stop soon.
Supports REST, WebSockets and MQ protocols.
Pro Open Source
Kuzzle is open source and it's released under the Apache 2 License.
Pro Realtime through filters
You do not connect to classic rooms but to search filters and can be warned of changes on permanent storage or volatile one.
Con Uses MongoDB for the backend, which is not considered very safe by many
Back4App uses MongoDB as the database where data is stored. Mongo has been known to have issues with data corruption and data loss.
Con No hosted version
Kuzzle has no hosted version. In order to use it, you have to install it to a remote machine. This can be cost-effective but it also adds overhead because you will have to take care of the hosting and backend infrastructure yourself.
Con May have issues since it's stil la relatively young project
Kuzzle is (as of February 2nd, 2015) in alpha version and approaching beta.