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
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.

Additional Considerations for Apex in an Offline-Enabled Mobile App

The following differences in behavior compared to Apex run from a browser-based connection apply to Apex when used in Lightning web components in an offline-enabled mobile app.

If a quick action uses a wired Apex method, and that quick action is primed at app startup, then the Apex results data can be primed as well, and available offline. The LWC must be statically analyzable for priming to take place. Specifically, input parameters for the wire adapter must be analyzable. For example, if the input parameters are derived from page reference attributes, or from the output of another LDS wire that is also analyzable. See Validate Lightning Web Components for Offline Use for additional details about static analysis. Note that the Apex method will be invoked during priming, possibly many times, to prime results for all possible adapter input parameters.

Apex continuations are supported. However, because continuations tend to be longer running requests, we recommend providing feedback to the user while a continuation is active. Otherwise, they might go offline before a continuation completes, which results in an error.