If you're a mobile developer, you don't have many choices when it comes to storage using database. For long time the major option was SQLite and still it is, after more than ten years after release. Finally we can try something much more fresh and something really serious.
Realm is an open-source library that mobile developers can integrate into their app to store and query data. Data is queried from Realm's internal storage engine, which runs on your device and is built to get the best performance. The internal storage engine has been developed from the ground up to be memory-efficient, and provide the best performance to developers.
Realm's iOS implementation (both Objective-C and Swift) shows the library to be well-constructed, using common data structures like objects and arrays. According to the documentation Realm provides important features, such as thread-safety, a simple API around data and easy linking of data and also boasts a better performance over other implementations (like Core Data).
After launching a demo application provide on github, I was positively surprised. Realm is in deed fast - 50k inserted records in less than 4 seconds.
It is a really good opportunity to test it in my current application. In need to manage many records in order to present data on map view. For some reasons I've decided to not use Core Data for that task - mainly because saving big chunk of data is really slow in core data. Now the idea is to use Realm to manage data needed for maps and for the rest to use apple's Core Data with SQLite. I will share with you my thoughts about Realm after some more advanced tests.
Official site: realm.io