Flutter, the renowned cross-platform mobile framework, has been gaining immense popularity among developers worldwide. As the Flutter community expands, the demand for efficient Flutter databases is also increasing. Developers now have access to a range of Flutter database options that cater to various needs and preferences.

In this article, we’ll focus specifically on local storage solutions, as these are essential for enabling offline functionality, improving performance, ensuring data persistence, enhancing data privacy and security, and supporting edge computing capabilities. Furthermore, local data storage is needed to promote sustainability. Let’s dive into the current local database landscape for Flutter and compare the most popular options.

Flutter databases / Flutter Dart data persistence

While the database market is huge and dynamic,  there are only few options to choose from if you are a Flutter / Dart app developer. Before we dive into the Flutter database options, advantages and disadvantages, we’re taking a very quick look at databases to make sure, we share a common ground. 

What is a database?

A database is a piece of software that allows the storage and systematic use of digital information, in other words: data persistence. As opposed to mere caching, data is reliably stored and available to work with unless actively deleted. A database typically allows developers to store, access, search, update, query, and otherwise manipulate data in the database via a developer language or API. These types of operations are done within an application, in the background, typically hidden from end users. Many applications need a database as part of their technology stack. The most typical database operations are CRUD: Create, Read, Update, Delete.

What are the major types of databases?

There are many types of databases. For our purpose, the most important differentiations are non-relational (NoSQL) versus relational databases (SQL), cloud databases versus edge databases, and maybe embedded versus in-memory. However, databases can be further distinguished by additional criteria e.g. the data types they support, or the way they scale – and definitions can vary.

What is an ORM?

An Object relational Mapper (ORM) is not a database. We’re bringing this up mainly, because we see it confused often. It is a layer that sits on top of a database and makes it easier to use. This is typically especially relevant when the database is a relational database (SQL) and the programming language used is object-oriented. As noted above, Dart is an object-oriuented programming language.

The Flutter local data persistence landscape

There are several Flutter databases that provide offline support, offering the ability to store and access data locally even without an internet connection. Here are some of the notable options:

• Hive is a lightweight key-value database written in Dart for Flutter applications, inspired by Bitcask.
• ObjectBox DB is a highly performant lightweight NoSQL database with an integrated Data Sync. It stores objects.
• sqflite is a wrapper around SQLite, which is a relational database without direct support for Dart objects. 
• Drift is a reactive persistence library for Flutter and Dart, built ontop of SQLite. 
• Floor is another ORM on top of SQLite.

What is the best offline Flutter Dart database?

This of course depends… Make up your own mind with the following comparison matrix as a starting point. Note: With very few options to choose from, the following overview is sometimes a bit like comparing apples 🍎 and pears 🍐.

Flutter Database performance benchmarks

As with any benchmark, you need to take a look at the details. We take benchmarking very serious and strive to get accurate results. Therefore, we also always open source the benchmarking code and encourage you to check it out. If you note anything that does not even out in your oppinion, do let us know. We have a long history of updating and improving our benchmarks continually and are happy to take any recommendations.

Performance Benchmark Test Setup

We used an Android 10 device with a Kirin 980 CPU to run the benchmarks as a Flutter app. The app executed all operations (ops) in batches of 10.000 objects. Each batch formed a single transaction. We ran each test 50 times. The results you see in the diagram are averages across all runs. We set it up that way to ensure that neither the Virtual Machine warmup during the first run nor the garbage collections affect the overall result significantly. 

Flutter Databases CRUD Performance Results

Summary of the Flutter Dart DB Benchmarks

Hive and ObjectBox clearly outperform sqflite across all CRUD operations. The results show ObjectBox performing with up to 70 times the speedup for create and update operations. With regards to comparing Hive and ObjectBox, the results vary more. Hive can be faster at reading objects than ObjectBox. However, strictly speaking it’s not a fair comparison, because in Hive, the high read numbers result from Dart objects already cached in memory. If the objects are fetched using the async API from disk, the numbers drop by factor 1000.

Drift and Floor were not part of the benchmarking as they are ORMs. However, it is very likely they will perform similarly to sqflite, reflecting primarily the performance of SQLite.

Flutter Data persistence – Conclusion

Recently, the Flutter database landscape has experienced significant growth and diversification. With Flutter’s increasing popularity, developers now have a number of database options available. In this article, we focused on the best local databases, comparing their features in a comprehensive matrix, and showcasing performance benchmarks. In the end, the best choice depends on the specific needs of each project. The Flutter database landscape in 2023 is a thriving ecosystem, continuously evolving to meet the changing needs of Flutter app development. One upcoming change that we can see is the rise of vector databases for AI. So, we encourage you to keep an eye on the lively market of Flutter databases not to miss any important updates.

If you want to get started learning how to use a database, we suggest you check out this video tutorial series that teaches you how to build a Flutter app with ObjectBox from scratch.