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Hacker Blue
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Firefox.

HackerBlue for Firefox is a dark theme for Firefox's toolbars, tabs, address bar, menus and sidebar: deep navy surfaces, steel-blue text and one bright blue accent. One payment for the theme, updates included at no extra charge, and up to three personal devices.

Choose themes

$2.99 for Firefox, less per theme when you pick more.

One-time payment. Limited-time offerAll 32 themes for $29.99 $92.69 if bought singlyEnds 15 November 2026

One-time purchase / 3 personal devices

Firefox running on Linux with HackerBlue: a navy tab strip and toolbar, a dark address bar and a navy new-tab page.

Firefox 157 (Developer Edition) running on Linux with HackerBlue enabled, captured from the running app.

How to install

Three steps in your device's terminal. Every command is exactly what you type; copy it, paste it, press Enter.

  1. Put the HackerBlue program on your device

    Linux or macOS: Terminal
    curl -fsSL https://hackerblue.dev/install.sh | sh
    Windows: PowerShell
    irm https://hackerblue.dev/install.ps1 | iex

  2. Sign in

    Terminal
    hackerblue login

    A page opens in your browser; sign in to your Hacker Blue account and choose Approve.

  3. Install the Firefox theme

    Terminal
    hackerblue install firefox

    Restart Firefox, open Add-ons and themes → Themes and enable Hacker Blue: Firefox lets you turn a theme on only there.

A file of yours in the same place is never overwritten.

Updates come with your licence: hackerblue update firefox when a newer version is out. hackerblue uninstall firefox removes its theme files. Finish removal in your browser and choose your previous theme. Every command, and the rest of the guide: the install guide.

Firefox, default and in HackerBlue

The same view twice. The switch changes only the theme.

Firefox with its default look: a light grey tab strip and toolbar above an example page. Firefox with HackerBlue: the same page under a deep navy tab strip and toolbar with a cyan tab outline.

Firefox 154 running on Linux, the same page in its stock default look and in HackerBlue. Captured from the running app in a throwaway profile.

Firefox belongs to its owner; Hacker Blue is not affiliated with or endorsed by it.

The theme

HackerBlue for Firefox is a Firefox theme, the same kind you would add from Firefox's own Add-ons and themes page. It colors the tab strip, toolbars, address bar, bookmarks bar, menus, sidebar and new-tab page, and it asks for no permissions and runs no code.

It is a dark theme, made and checked with Firefox 157 (Developer Edition) and release Firefox 154 on Linux. Firefox installs only themes that Mozilla has signed, so this one has been: Mozilla signed it as a private, unlisted add-on, and it has no public page on Mozilla's add-ons site.

What the purchase includes

one-time
  • Purchase One-time

    One payment for HackerBlue for Firefox. There is no subscription and nothing renews.

  • Updates Included

    Updates Hacker Blue publishes for this theme come with the licence at no extra charge; a version change never asks you to pay again.

  • Devices 3 active

    The licence covers up to three personal devices active at the same time, and you can deactivate one from your account page.

  • Delivery HackerBlue CLI

    The CLI downloads and installs the theme on an authorised device.

Pricing for Firefox

The purchase runs on Whop, and Whop shows the price, currency and taxes before you pay. Buying ties the licence to a Hacker Blue account, which you use with Google or an email address and a password.

Choose themes

$2.99 for Firefox, less per theme when you pick more.

One-time payment. Limited-time offerAll 32 themes for $29.99 $92.69 if bought singlyEnds 15 November 2026

HackerBlue Complete is the other one-time product: it includes the Firefox theme today and the themes added to Complete later, under the same kind of licence. Pricing compares the two.

Release notes

What changed in each release. Updates are included with the licence.

1 release

Each release has its own version. Versions follow semantic versioning:

  • Major: the look changes noticeably.
  • Minor: support for new parts of the app.
  • Patch: fixes.

The newest release is first.

  1. 1.0.025 September 2026

    First release.

Terms, support and the rest of the family

License sets out what the purchase lets you do with the theme files; three active personal devices, no redistribution or resale. Refund covers refunds and the EU, EEA and UK 14-day withdrawal right, and Legal has the terms of sale. Contact has the ways to reach us.

The rest of the family

32 themes are available now.

31 themes