Mobile and Offline Developer Guide

Mobile App Development with Lightning Web Components and LWC Offline
Create Mobile-Ready Components
Use Mobile Device Features in Mobile Apps
Offline Considerations and Limitations
Offline Environment Details
Use Salesforce Features While Offline
Use GraphQL While Mobile and Offline
Use Apex While Mobile and Offline
Use Apex in Lightning Web Components While Online
Enable Caching of Apex Results
Apex Results Are Separate from Other Primed Data
Understand Apex Behavior While Offline
Apex Wires While Offline
Imperative Apex While Offline
Refresh Records Cached in Durable Store While Offline
Additional Considerations for Apex in an Offline-Enabled Mobile App
Additional Documentation for Apex in Lightning Web Components
Use Images in an LWC Offline-Enabled Component
Upload Images While Offline
Use Third-Party JavaScript in an LWC Offline-Enabled Component
Navigation
Development Tools and Processes
Quick Start Tutorials
PDF

Note: This release is in preview. Features described here don’t become generally available until the latest general availability date that Salesforce announces for this release. Before then, and where features are noted as beta, pilot, or developer preview, we can’t guarantee general availability within any particular time frame or at all. Make your purchase decisions only on the basis of generally available products and features.

Understand Apex Behavior While Offline

Additional features that are built into offline-enabled apps allow the app, including Lightning web components and even Apex, to continue to function. Knowing these features, and their limitations, is critical to writing LWCs that function well, even without a connection to the Salesforce service.

The standard Salesforce web interface requires a continuous network connection to the Salesforce service. When a standard Salesforce client, such as a desktop browser, is offline, features that require a connection to the Salesforce service—which is most features—don’t work. Since Apex runs on the Salesforce service, this includes all Apex-based features of Lightning web components.

An offline-enabled mobile app, in contrast, is designed to continue to function even when no connection to the Salesforce service is available. The offline features of the app aren’t magic; data that’s not already available on the client device is inaccessible. But carefully designed features, including Lightning web components that use Apex, can continue to run with data that’s available locally, on the device, even without a network connection.