When comparing Back4App vs Kuzzle, the Slant community recommends Back4App for most people. In the question“What are the best alternatives to Firebase?” Back4App is ranked 1st while Kuzzle is ranked 2nd. The most important reason people chose Back4App is:
The platform is reliable allow to scale up the applications running on it.
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 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.
Pro Open Source
Kuzzle is open source and it's released under the Apache 2 License.
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 May have issues since it's stil la relatively young project
Kuzzle is (as of February 2nd, 2015) in alpha version and approaching beta.