CoreData vs Realm: What are the differences?
CoreData: A framework that is used to manage the model layer objects in your application. It is an object graph and persistence framework provided by Apple in the macOS and iOS operating systems. It allows data organized by the relational entity–attribute model to be serialized into XML, binary, or SQLite stores. It provides generalized and automated solutions to common tasks associated with object life cycle and object graph management, including persistence; Realm: Realm makes it easy to build reactive apps, realtime collaborative features, and offline-first experiences. The Realm Mobile Platform is a next-generation data layer for applications. Realm is reactive, concurrent, and lightweight, allowing you to work with live, native objects.
CoreData belongs to "Object Relational Mapper (ORM)" category of the tech stack, while Realm can be primarily classified under "Mobile Database".
Realm is an open source tool with 13.4K GitHub stars and 1.74K GitHub forks. Here's a link to Realm's open source repository on GitHub.
According to the StackShare community, Realm has a broader approval, being mentioned in 59 company stacks & 51 developers stacks; compared to CoreData, which is listed in 8 company stacks and 3 developer stacks.