Cert Canary

Name: Cert Canary
Author: David Tucci

By: David Tucci

Warns of pending certificate expiration

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Features & Capabilities

Cert Canary is a browser extension designed to warn if a TLS certificate is near expiration.

A yellow warning box will appear if a page results in a request served with a certificate due to expire within 30 days. If there are fewer than 15 days until the certificate expires the warning box will be red.

Clicking on the canary icon will show a list of domains the page has requested, color coded based on the time to their certificate expiration.

User Growth & Download Statistics

Add-on

By:

David Tucci

Daily users:

Version:

0.2 Last updated: 2026-02-12

Version code:

6148043

Creation date:

2021-09-22

Risk:

Permissions:

Size:

31.52KB

URLs:

Website

Full description:

Source:

Firefox Add-ons Store

Data ingested on:

2026-06-16

Compare stats and ranking:

Ranking

# 54,520 ▼ 239

For Developers

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Contact the developer

Chrome-Stats does not own this Firefox add-on. Please use these information below to contact the Firefox add-on developer.

Developed by:

David Tucci

Firefox Add-ons Store

https://addons.mozilla.org/firefox/addon/cert-canary/

Website:

https://github.com/davidtucci/cert_canary

Is Cert Canary Safe?

Risk impact

Risk impact measures the level of extra permissions an extension has access to. A low risk impact extension cannot do much harms, whereas a high risk impact extension can do a lot of damage like stealing your password, bypassing your security settings, and accessing your personal data. High risk impact extensions are not necessarily malicious. However, if they do turn malicious, they can be very harmful.

Cert Canary requires some sensitive permissions that could impact your browser and data security. Exercise caution before installing.

Risk impact analysis details

Critical Allows access to all websites, posing a significant security risk as it can monitor and modify data from any visited site.
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Risk likelihood

Risk likelihood measures the probability that a Firefox add-on may turn malicious. This is determined by the publisher and the Firefox add-on reputation on Firefox Add-ons Store, the amount of time the Firefox add-on has been around, and other signals about the Firefox add-on. Our algorithms are not perfect, and are subject to change as we discover new ways to detect malicious extensions. We recommend that you always exercise caution when installing a Firefox add-on.

Cert Canary is probably trust-worthy. Prefer other publishers if available. Exercise caution when installing this add-on.

Risk likelihood analysis details

High This extension has low user count. Unpopular extensions may not be stable or safe.
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