Basilisk
A classic-style open source browser with legacy plugin support.
Basilisk is a free, open source desktop web browser built on the UXP platform and Goanna rendering engine rather than Chromium or modern Firefox. It emphasizes a traditional interface, slower-paced changes, and compatibility with workflows that depend on older browser technologies such as NPAPI plugins and XUL extensions.
Why it stands out
- Maintains support for NPAPI plugins and XUL extensions that most mainstream browsers have dropped.
- Uses an independent Mozilla-derived engine rather than Chromium, adding real browser-engine diversity.
- Prioritizes continuity and predictable behavior over rapid UI churn.
- Developed independently from Mozilla, Firefox, Moonchild Productions, and Pale Moon despite related technical roots.
Good to know
- Desktop-focused; the page does not describe mobile or web-app versions.
- Its extension compatibility centers on XUL-style add-ons, so modern Firefox/Chrome extension expectations may not apply.
- The project’s deliberate update pace may not suit users who want the newest browser features as soon as they appear.
Under the radar: When looking for extensions, start with Basilisk-compatible XUL add-ons rather than assuming current Firefox Add-ons listings will work.
Photos
Archivists, preservation hobbyists, and legacy-environment maintainers can run web workflows that still rely on NPAPI plugins or XUL-era extensions. Use a browser that changes gradually instead of adopting frequent interface redesigns. Test website behavior outside the dominant Chromium and Firefox engine families. Keep a customizable, classic desktop browsing setup for long-term use.
Desktop browser based on UXP and the Goanna rendering engine; customizable traditional interface; support for HTML5, modern CSS, scripting, WebRTC, and downloadable fonts; continued support for NPAPI plugins and XUL-based extensions; public source repository and release notes.
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Similar sites elsewhere
- Pale Moon — palemoon.org
- Waterfox — waterfox.net
- LibreWolf — librewolf.net
- SeaMonkey — seamonkey-project.org
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