While Internet coverage grows each year, and in some countries like the US, where almost 95% of the population has access to the Internet, substantial connectivity gaps still exist. Businesses that operate in or serve rural and remote areas more than anyone else understand the pain of these gaps. A halt of the entire operation grinds as soon as the app the delivery driver uses to update inventory and manage deliveries goes offline – not a pleasant scenario for companies. That’s why React Native offline first mobile development gained popularity among product and business owners.

So, how to make your app that operates offline? Relying on our experience in React Native development, we’ll walk you through the process of the creation of the offline-first application and share some expert tips.  

What is Offline-First Architecture?

Well, the concept is quite simple and straightforward. Offline-first design is a software development approach that lets companies build applications to work seamlessly without access to the Internet. Such apps deliver most or all of their core features to users regardless of the Internet connectivity. The trick is that offline-first apps store data locally – on the user’s device, which allows the application to continue working offline. Once a connection is reestablished, the app automatically syncs all offline changes to a remote server.  

It starkly contrasts with the traditional online-first approach, where Internet connectivity is assumed for most functionalities. In online-first apps, features are limited or completely unavailable offline, which degrades the user experience. 

Here’s a table that highlights the key differences of the two designs:

Feature	Offline-first architecture	Online-first architecture
Data storage	Local device first	Remote server first
Core functionality	Optimized for offline use	Reliant on Internet
Data consistency	Eventual consistency	Real-time consistency
User experience (offline)	Smooth and functional	Limited or unavailable

Don’t think that offline support is only a necessity in remote locations. Since slow connections, network outages, and areas with weak reception are still common issues nowadays, the offline-first concept should be the standard approach for any app development. 

Consider this: every time your customer takes a subway, a plane, or an underground parking, the connectivity might drop, and they can’t use your app. The same applies to businesses, let’s say, delivery, logistics, or field services, where employees often find themselves in areas with unreliable Internet access. So, opting for offline functionality does make sense.

Key Components of Offline-First Apps

The major element that enables mobile apps to work offline is the data management approach. To cut the cord on Internet reliance, you should keep data storage and processing within the app itself. Yet, it’s equally important to ensure that this data can be exchanged with other users and that any modifications are immediately and precisely updated across the entire app environment.

In a nutshell, you’ll need:

• Data synchronization. This ensures data consistency between the user’s device and the remote server. Once the Internet connection is restored, the app synchronizes any local changes with the server. Techniques like optimistic or pessimistic locking can be employed to handle potential conflicts that may arise from offline data modifications.
• Local data storage is the foundation of offline-first functionality. Offline React Native developers use different technologies, like IndexedDB or SQLite, to let applications store essential data locally on the user’s device. This cached data can be accessed anytime, whether via the Internet or not.
• Network detection and management. The app needs to be constantly aware of the user’s Internet connection status. Techniques like network listeners monitor connectivity. When online, the app can fetch fresh data or synchronize any local changes. Conversely, when offline, the app gracefully adapts and relies on the locally stored data.

What is React Native Offline First?

React Native, the popular framework for cross-platform mobile app development, takes a fresh approach with offline support. Instead of assuming you’re always connected to the web, it prepares for the opposite and puts offline functionality front and center. Due to this concept, the app’s core functionality performs seamlessly, even when the Internet decides to take a break. 

Here’s how offline first React Native makes it possible:

• Native features. It leverages powerful native device functionalities, like local storage options (SQLite), which let you store data directly on the user’s device for offline access.
• Cross-platform capabilities. You can build one codebase that tackles offline challenges on both iOS and Android that saves you time and resources.
• Rich Library Ecosystem: Open-source libraries like React Native Offline or Redux Offline streamline development by handling network detection, data synchronization, and conflict resolution.

So, it’s clear that React Native offline mode solves the problem of restricted functionality. Yet, the additional benefit of this approach is a faster and smoother user experience. The fact is local data storage and synchronization only when necessary eliminates the need for constant network requests. Due to this, apps can respond more rapidly to user inputs irrespective of the Internet connection strength (3G, 4G, 5G connectivity, or no Internet at all). To sum up, offline functionality reduces lag, enhances usability, and always delivers responsive UI even in connectivity dead zones.    

How to Build React Native Offline First App

If the advantages of React Native offline first capabilities have inspired you to build a reliable application to support your business operations, you need to know where and how to begin. Here’s a five-step guide Relevant developers follow to develop quality, lag-free offline React Native applications.  

1. Set Up Your React Native Environment

React Native environment setup for an offline-first app might sound like a tech odyssey, but with the right tools, it’s the same as putting together some high-tech Lego bricks. We’ll skip over the common setup steps for React Native projects, which involve the installation of Node.js, npm, the React Native CLI, and platform-specific development tools (Xcode for iOS, Android Studio/SDK for Android). Because these procedures are similar for both online-first and offline first React Native applications. 

Instead, we move straight to the selection of the right library for your app. Let’s focus on the three most optimal libraries that will make your app resilient and responsive, even in the digital wilderness. 

1. AsyncStorage: This built-in React Native library provides a simple key-value store to persist data locally on the user’s device. It allows you to cache data fetched from your API or store crucial application data so that your app can display cached information when offline.

When to use: Ideal for simple data storage like user preferences, app settings, or small amounts of cached data fetched from your API.

2. Redux Offline: If your app utilizes Redux for state management, you should definitely use Redux Offline to simplify offline scenario management. It enables you to define actions that can be performed offline and automatically synchronize them with your server when the Internet becomes available. 

When to use: If you already manage the app state with Redux and need offline functionality for actions and data updates.

3. Realm for React Native: For more complex data management needs, consider Realm. This React Native offline database offers offline storage, real-time synchronization, and powerful object-oriented API features. With it, you can easily store, query, and manage data locally on the user’s device.

When to use: When you need a robust solution for complex data management, offline storage, real-time synchronization, and advanced query capabilities.

How to integrate the library into the project: install the necessary library with the help of your package manager, then wire them into your app’s logic to handle data storage, state management, and synchronization tasks.

2. Implement Offline Data Synchronization in React Native

To ensure smooth operation between your app’s offline and online modes, you should develop and implement solid data synchronization methods. They may differ based on your backend architecture, but the basic principle is to track changes made while offline and update the server once connectivity is restored. So, let’s see how to manage data synchronization between the local database and the remote server. 

1. Data Queuing and Background Sync:

• Queuing offline actions. To manage server load and enhance overall app performance, you need to prioritize data changes that are critical for immediate updates and queue others that can wait. When the user performs actions while offline, store them in a local queue. Libraries like react-native-background-fetch or react-native-background-task can be used to schedule background tasks that trigger synchronization with the server once an Internet connection is available.
• Background synchronization. In an offline-first app, when a user performs actions or makes changes while disconnected, these updates are stored locally. Background sync then takes over and periodically checks for Internet availability. Once a connection is detected, it automatically syncs the stored data with the server. This process is seamless—users might not even realize that syncs are happening, yet their data remains consistent across devices and sessions.

Although background sync empowers offline functionality, it also throws a curveball: data synchronization conflict. It typically happens when two users edit the same document offline, or one user works on it across multiple devices. When the app reconnects to the Internet and tries to merge offline changes with those made online by others, it can encounter a data synchronization conflict. Here’s what you can do to resolve the conflict:

• Apply optimistic or pessimistic locking:
  • Optimistic allows immediate updates to both local and server data so that the conflict resolution happens later during synchronization. Thanks to it, you can achieve a faster user experience, yet you may face data inconsistencies.
  • Pessimistic prevents local updates until confirmed by the server, which ensures data consistency but can potentially delay user actions.
• Conflict detection and resolution: Implement mechanisms to detect conflicts that arise from concurrent modifications on both the local device and server. Libraries like Redux Offline can help manage conflict resolution strategies like the overwrite of local changes or data merges.

Yet, we wouldn’t advise you to build data sync yourself. Either look for a database that already offers mobile sync or hire experienced React Native developers who can deal with this. If you wonder how much it can cost to hire a professional programmer, check our guide on React developer hourly rates. 

3. Implement Local Storage

As we have seen, local data storage is one of the key enables for offline functionality. So, the next step is to pick and employ the local storage solution. Here, you also have several options:

• Key-value store is simple storage for key-value pairs (numbers, strings, etc.).
• Local database is a structured storage that uses SQL queries.
• NoSQL database is flexible data storage with object-oriented API.

Here is the table with more details on each solution, along with examples.

Local storage type	Key features	When to use	The best solution
Key-value store	Simple storage and retrieval	Ideal for small amounts of data like user preferences or app configurations.	AsyncStorage: Store user login token: AsyncStorage.setItem(‘token’, ‘my_secure_token’).
Local database	Efficient data management and query capabilities.	For complex data structures and relational queries.	SQLite: Manage a to-do list database with tasks, due dates, and priorities
NoSQL database	Powerful query features, real-time synchronization, and offline storage.	For flexible data storage with object-oriented API and offline capabilities.	Realm: Store product information with details like name, price, and images for offline browsing.

From the experience of our React Native developers, we share the steps to implement local storage on the example of the Realm solution. It offers a powerful and user-friendly approach to React Native offline storage. Here’s a glimpse into the process:

1. Install the realm package with the help of npm or yarn.
2. Define your data structure using Realm’s object-oriented schema.
3. Use Realm’s API to easily store, retrieve, and query data locally.
4. Integrate Realm with your chosen synchronization library (e.g., Redux Offline) to seamlessly synchronize local data with your remote server when connectivity is available.

4. Build a Robust Network Layer

A network layer for your React Native offline first app is the same as a smart electrical grid in a city. it must handle fluctuations in power supply in a way to avoid blackouts. Just as the grid manages power supply fluctuations without a hitch, your app needs to smartly detect network availability and handle any changes in connection status. Here are some techniques and tips to help you create a sound network layer.

1. Network Detection

Libraries like NetInfo or react-native-NetInfo can be used to monitor the network connection status. They allow the app to adapt its behavior in accordance with connectivity like appropriate message display or retry of the data operations when online.

2. Network Status Management

Implement logic to gracefully handle changes in network status. This might require a pause in current network operations when offline, a queue of actions for later execution, and informative messages displayed to the user.

3. Offline-First Network Requests

Design your network requests to be resilient to offline conditions. Implement mechanisms like retries with exponential backoff to handle temporary network outages and ensure successful data retrieval when connectivity is restored.

4. Cache Mechanisms

Leverage cache mechanisms to store frequently accessed data locally. It will help you reduce the need for repeated network requests and improve app performance, especially in areas with poor internet access.

To develop a network layer that supports offline functionality, you need to create a set of functions and logic that handle network interactions. This layer should:

• Provide clear abstractions for network requests and responses.
• Automatically handle common network errors and timeouts.
• Integrate with your chosen local storage solution for caching and offline data management.
• Offer flexibility to adapt network behavior based on the current network status.

5. Test and Debugg Offline-First Features

To ensure your React Native offline app doesn’t become a digital paperweight when the Internet connection falters, you should properly test the app. It will help you see how your application performs under real-world scenarios, particularly plane mode, low battery, and poor network connectivity. Let’s review some tools that will let you test offline functionality.

• Emulators and simulators. Utilize Android emulators or iOS simulators to test your app’s behavior under various network conditions (e.g., slow connections, plane mode).
• Network mocking libraries: Tools like react-native-mock-async-storage or nock allow you to mock network responses and simulate different network scenarios to test.
• Testing Frameworks: You can use frameworks like Jest or React Testing Library to write unit and integration tests that specifically target offline functionality.

Once you identify your app’s weak points, fix them. To optimize your app’s performance, utilize the React Native offline track feature to monitor and adjust how data is handled when there’s no Internet connection. Pay special attention to data synchronization and check whether there are any conflicts. If so, implement appropriate conflict resolution strategies (optimistic/pessimistic locking merging algorithms) to ensure data consistency and prevent data loss. 

Case Study

We want to show you how it’s possible to integrate offline functionality into a mobile application in the example of our case. 

Facilitron is a comprehensive management system for community spaces that needed a solution to help staff compile property data and images for venue rentals. The challenge was to transform a labor-intensive, manual procedure into a streamlined, automated process that could function reliably even without internet access. This React Native application lets users add new property images and data (add other offline functionality).  

Our team achieved this offline support through the development of offline data storage and synchronization capabilities. Thanks to the React Native offline database, all images and data captured by Facilitron staff in remote areas with poor Internet connectivity would be automatically saved locally on their devices. Once an Internet connection is reestablished, the app syncs the new data with the central server without any user intervention. As a result, Facilitron app users can be sure that the images they took or uploaded on a device are consistent and up-to-date across all connected devices and servers.

Build a React Native Offline First with Relevant

React Native offline first development not only shields your app from the frustrations of slow or nonexistent Internet connections but also enhances the user experience substantially. Therefore, we believe this strategy should be a default design practice for modern mobile apps.

The development of the React Native application with offline support might be difficult and burdensome due to data synchronization complexities and user experience management between online and offline modes. If you lack the required expertise in-house, you might want to hire React Native developers with a proven track record in developing offline first apps. Relevant experts have all the necessary skills and knowledge to help you create a high-quality application that meets your requirements. Contact Relevant Software to discuss the details of your React Native project.