# Cert Canary

> Warns of pending certificate expiration

Canonical page: [https://chrome-stats.com/d/cert-canary](https://chrome-stats.com/d/cert-canary)

## Overview

- **ID:** `cert-canary`
- **Platform:** Firefox
- **Type:** Firefox add-on
- **Status:** Available
- **Publisher:** David Tucci
- **Category:** web-development
- **Daily users:** 1
- **Version:** 0.2
- **Last updated:** 2026-02-12
- **First published:** 2021-09-22
- **Size:** 32 KB
- **Data as of:** 2026-09-09
- **Store listing:** [Firefox Add-ons Store](https://addons.mozilla.org/firefox/addon/cert-canary/)
- **Website:** [https://github.com/davidtucci/cert\_canary](https://github.com/davidtucci/cert_canary)

## Description

Cert Canary is a browser extension that alerts users when a TLS certificate is near expiration. It displays a color-coded warning box for pages with expiring certificates and provides a list of the domains requested with their time to expiration.

## Rankings

- #105,330 — Overall

## Permissions and access

### Permissions

- `webNavigation`
- `webRequest`
- `webRequestBlocking`
- `<all_urls>`

## Safety

- **Risk impact:** High risk impact
- **Risk likelihood:** Moderate risk likelihood

### Analysis details

- Allows access to all websites, posing a significant security risk as it can monitor and modify data from any visited site.
- This extension has low user count. Unpopular extensions may not be stable or safe.

> Some risk analysis details are omitted from this free response. [Upgrade to view the full analysis](https://chrome-stats.com/pricing).

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- [CertiSafeGuard](https://chrome-stats.com/d/certisafeguard) — 16 users

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Source: [Chrome-Stats](https://chrome-stats.com/d/cert-canary)