Firefox Could Get a Major Speed Boost With Microsoft's Accelerated App Launches

Mozilla is testing Microsoft’s Accelerated App Launches feature in Firefox, which could make opening new browser windows faster on Windows 11.

According to a Mozilla Bugzilla report, early testing showed that launch requests reached an already-running Firefox instance more than 20 times faster than before.

The feature remains experimental, and Mozilla has not announced when users can expect it.

Firefox tests Microsoft’s Accelerated App Launches

Firefox product manager David Rubino confirmed that Mozilla successfully accessed Microsoft’s accelerated launch API using its existing taskbar-pinning unlock code.

In a local test, traditional launch requests took approximately 70 milliseconds to reach an existing Firefox instance, while Accelerated App Launches reduced that time to just 3 milliseconds.

However, these numbers measure how quickly Windows delivers a launch request to an existing Firefox instance, not the browser’s complete startup time.

Mozilla also confirmed that launch requests from the Windows 11 Start menu could reach the running browser directly.

Developers have introduced a new experimental preference, widget.windows.accelerated_launch.enabled, which remains disabled by default.

Mozilla still needs to address how the feature handles multiple Firefox profiles before considering a wider rollout.

How Accelerated App Launches work on Windows 11

When users open an application that’s already running, Windows typically creates a temporary process to forward the launch request to the existing instance.

Microsoft’s Accelerated App Launches removes that extra step and sends the request directly to the running application.

This reduces the delay between clicking an app icon and receiving a response from the existing process.

For Firefox users, the improvement could make opening additional browser windows feel more responsive. However, it doesn’t necessarily improve cold startup times when Firefox isn’t running.

Firefox could receive the same speed boost as Microsoft Edge

Microsoft has already introduced Accelerated App Launches for Edge, and Mozilla’s testing suggests that Firefox could benefit from the same Windows 11 capability.

However, the initial performance results come from a single local development test. Mozilla still needs broader testing before confirming how much faster Firefox will feel in everyday use.

The company hasn’t provided a release date.

In other Firefox developments, Mozilla is testing browsing journeys in Smart Window and working on a feature that lets users lock private browsing windows.

Via Neowin