Certificate expiration

Name: Certificate expiration
Rating: 4.6667 (6 reviews)
Author: Johan

By: Johan

Shows how many days the website certificate has left until is expires.

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Features & Capabilities

Certificate Expiration Extension

Keep track of website SSL certificate expiration dates effortlessly with the Certificate Expiration Firefox extension. This simple tool displays the number of days left before the current website's SSL certificate expires directly in your browser toolbar.

The extension adds a padlock icon indicating certificate status—showing days remaining as a numeric overlay. If the certificate is nearing expiration (less than 29 days remaining), the icon turns red to alert you. For sites without encrypted connections, an unlocked red padlock icon is displayed, enhancing your awareness of security risks. Stay informed and browse safely with this lightweight and user-friendly extension.

User Growth & Download Statistics

Add-on Privacy & Security

By:

Johan

Daily users:

162 5

Rating:

4.67

(6)

Version:

3.0 Last updated: 2023-07-21

Version code:

5597605

Creation date:

2020-03-01

Risk:

Permissions:

Size:

52.49KB

URLs:

Website

Full description:

Source:

Firefox Add-ons Store

Data ingested on:

2026-06-19

Compare stats and ranking:

Ranking

# 8,900 ▲ 134

Other rankings

#32 in notification keyword 11

#72 in location keyword 38 ▲ 1

#105 in education keyword 10 ▲ 2

#109 in catalog keyword 7

#111 in category keyword 23 ▲ 1

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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:

Johan

Firefox Add-ons Store

https://addons.mozilla.org/firefox/addon/certificate-expiration/

Website:

https://github.com/johansigfrids/expirator

User Reviews

I installed this add-on in order to know when the certificate of a website is nearly ended. I've a remark: with let's encrypt decreasing the length of their certificates, the colour-changing padlock is often red whereas this is a 'normal' situation. I would be pleased if the colors could also depends on the ratio of the certificate period. Something like: certDays = Math.floor( (cert.validity.end - cert.validity.start) / factor ) color: diffDays < redline && diffDays < certDays/4 ? ... : ...

by Vi*****, 2026-02-05

Useful tool. Thanks.

by Ma*****, 2025-10-12

Great for being alert to SSL certificates that are about to expire. Note that the colour-changing padlock is a new button (it doesn't change the browser's existing padlock), and that in 2023-era Firefox you have to add this yourself. Firefox doesn't show it among the ‘Customise Toolbar’ buttons; instead, you now need to go to the ‘jigsaw’ button which lists extensions, then click on the gear for ‘Certificate expiration’ and choose ‘Pin to Toolbar’. You can then use ‘Customise Toolbar’ to drag it to where you want it. And also note that Mozilla blocks extensions on this Add-Ons site, so this isn't a good page for trying it out and seeing how it works!

by Sm*****, 2023-02-06

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Is Certificate expiration 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.

Certificate expiration 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.

Certificate expiration has earned a fairly good reputation and likely can be trusted.

Risk likelihood analysis details

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