Installation and upgrade

DownloadIt is a bootstrapped Firefox extension that uses internal browser APIs. It is not an AMO WebExtension and requires a compatible Loader before Firefox can load it.

Before you start

• Firefox 136 or later.
• Windows, or Linux with a distribution-native Firefox package or Mozilla tarball.
• A Firefox profile where you can install a compatible Loader.
• Snap Firefox, Flatpak Firefox, and macOS are not currently supported.

1. Install the dependency environment

All supported Firefox channels can use the customized userChrome.js-Loader. For Firefox Developer Edition and Nightly, you may use Bootstrap Loader instead.

userChrome.js-Loader

Download a compatible build from the userChrome.js-Loader project. Versions released after 20250219 are recommended for Firefox 135 and later.

Extract the Loader’s program files beside firefox.exe and its profile files into the Firefox profile you intend to use. Restart Firefox and confirm the Loader is active before continuing.

Caution

userChrome.js-Loader changes Firefox’s application and profile files. Use a dedicated profile or back up the affected files before installing it.

Bootstrap Loader

This alternative is available only on Firefox Developer Edition and Nightly. WebExtension Experiments are not available in Firefox Release, Beta, or ESR.

1. Open about:config, accept the warning, and set:

   xpinstall.signatures.required = false
   extensions.experiments.enabled = true

2. Download BootstrapLoader.xpi from the latest release assets.

3. Open about:addons, choose Install Add-on From File… from the gear menu, and select the XPI.

4. Restart Firefox and confirm that Bootstrap Loader is active.

Caution

These preferences reduce Firefox’s add-on signature and WebExtension Experiment restrictions. Use Bootstrap Loader only in a dedicated Developer Edition or Nightly profile.

2. Download DownloadIt

Download Nightly v2.14.0Pre-release

The current package is a Nightly pre-release. It is rebuilt from the master branch and may change more frequently than a stable extension.

3. Install the XPI

1. Open about:addons in Firefox.
2. Open the gear menu and choose Install Add-on From File….
3. Select the downloaded addon.xpi.
4. When DownloadIt asks to restart Firefox, choose OK to apply the installation immediately.

After restart, the DownloadIt button is added to the navigation toolbar. Firefox’s Customize Toolbar screen can move or remove it.

Upgrade

Download the latest Nightly XPI and install it over the existing copy using the same about:addons command. DownloadIt prompts for a restart after an upgrade.

The extension publishes a legacy update manifest, but the supported Loaders do not check or install updates automatically. Upgrades are manual.

Linux notes

Use a distribution-native package or Mozilla tarball. Local launchers configured for custom commands, aria2, uGet, or JDownloader must be executable. The bundled Aria2Next provider is available on Linux x86_64; other Linux architectures can still connect to an externally managed aria2 service.

Continue with Quick start.