LinkCage by Luis Yax
Extension alone won't work. Needs Docker + the LinkCage companion host. Risky links open in a sandbox. More: linkcage.app
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About this extension
LinkCage opens links you don't trust inside a throwaway, isolated browser - on your own computer - so nothing dangerous touches your real browser.
REQUIREMENTS (read before installing)
This add-on is one part of a three-part tool. It needs:
- Docker Desktop, installed and running, and
- The free, open-source LinkCage companion host (one-time install).
The add-on is only the trigger. Without Docker and the host it cannot launch a sandbox. Setup: https://linkcage.app
HOW IT WORKS
Right-click an untrusted link and choose "Open in LinkCage." The URL is handed, via native messaging, to the local companion host, which spins up a disposable Chromium browser inside an isolated Docker container. Malicious content stays in that container - never reaching Firefox, your files, or your credentials. Close it and the container is destroyed (RAM-only).
Before the page loads, the host checks the link against URLhaus and Google Safe Browsing and shows a SAFE / SUSPICIOUS / MALICIOUS splash.
PRIVACY
- No LinkCage cloud service; the add-on sends nothing to us.
- The add-on transmits the clicked URL only to the local companion host, over native messaging.
- The host performs the reputation lookup directly against URLhaus and Google Safe Browsing. In-sandbox browsing is not logged or transmitted.
- Open-source and auditable.
WHAT IT IS NOT
Not antivirus. It does not monitor or filter normal Firefox browsing. It isolates only the links you choose to cage.
Source & install: https://linkcage.app
REQUIREMENTS (read before installing)
This add-on is one part of a three-part tool. It needs:
- Docker Desktop, installed and running, and
- The free, open-source LinkCage companion host (one-time install).
The add-on is only the trigger. Without Docker and the host it cannot launch a sandbox. Setup: https://linkcage.app
HOW IT WORKS
Right-click an untrusted link and choose "Open in LinkCage." The URL is handed, via native messaging, to the local companion host, which spins up a disposable Chromium browser inside an isolated Docker container. Malicious content stays in that container - never reaching Firefox, your files, or your credentials. Close it and the container is destroyed (RAM-only).
Before the page loads, the host checks the link against URLhaus and Google Safe Browsing and shows a SAFE / SUSPICIOUS / MALICIOUS splash.
PRIVACY
- No LinkCage cloud service; the add-on sends nothing to us.
- The add-on transmits the clicked URL only to the local companion host, over native messaging.
- The host performs the reputation lookup directly against URLhaus and Google Safe Browsing. In-sandbox browsing is not logged or transmitted.
- Open-source and auditable.
WHAT IT IS NOT
Not antivirus. It does not monitor or filter normal Firefox browsing. It isolates only the links you choose to cage.
Source & install: https://linkcage.app
Rated 0 by 0 reviewers
Permissions and data
Required permissions:
- Exchange messages with programs other than Firefox
- Display notifications to you
Data collection:
- The developer says this extension doesn't require data collection.
More information
- Add-on Links
- Version
- 1.0.0
- Size
- 54.65 KB
- Last updated
- 4 days ago (Jun 2, 2026)
- Related Categories
- License
- Apache License 2.0
- Version History
- Add to collection
Source code, the one-time installer, and setup steps: https://linkcage.app and https://github.com/yaxzone/LinkCage
The add-on never contacts any LinkCage server. It hands the clicked URL to the local host over native messaging; the host runs the reputation check (URLhaus + Google Safe Browsing) and opens the link in a disposable Docker Chromium container that is destroyed when you close it.
Found a bug or have a question? Send me a message via https://linkcage.app/#contact