Lightning Aura Components Developer Guide

Introducing Aura Components
Quick Start
Creating Components
Using Components
Communicating with Events
Communicating Across the DOM with Lightning Message Service
Creating Apps
Styling Apps
Developing Secure Code
Using JavaScript
Working with Salesforce Data
Lightning Data Service
Using Apex
Creating Server-Side Logic with Controllers
Apex Server-Side Controller Overview
AuraEnabled Annotation
Creating an Apex Server-Side Controller
Using Apex to Work with Salesforce Records
Granting User Access for Apex Classes
Securing Data in Apex Controllers
Calling a Server-Side Action
Queuing of Server-Side Actions
Batching of Server-side Actions
Boxcar Grouping and Optimization
Manage Synchronous Action Dependencies
Disable Dynamic Boxcar Optimization for Aura Actions
Foreground and Background Actions
Storable Actions
Abortable Actions
Action Limits and Considerations
Testing Your Apex Code
Making API Calls from Apex
Make Long-Running Callouts with Continuations
Creating Components in Apex
Testing Components
Debugging
Performance
Reference
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.

Disable Dynamic Boxcar Optimization for Aura Actions

Dynamic boxcar optimization improves performance for most Lightning components and apps, including Lightning Experience itself. If your org has components that are adversely affected by dynamic boxcar optimization, you can disable it for your org in Setup.

Dynamic boxcar optimization was introduced in Winter ’26, and improves the performance of the Lightning Components Framework for all orgs. You should only disable it if your component code contains timing dependencies that depend on standard boxcar grouping. Treat such dependencies as software defects that need to be corrected.

  1. From Setup, in the Quick Find box, enter Session Settings, and then select Security | Session Settings.
  2. In the Aura action Settings section, check the Disable new Aura boxcar mechanism that efficiently batches Aura actions across available XHR slots for optimal performance option.
  3. Click Save.

We strongly recommend that you only disable dynamic boxcar optimization as a temporary measure while you correct your component code. Sequential or synchronous timing dependencies in your code are to be avoided, no matter which boxcar’ing strategy is enabled for your org.