Block Site: A Website Blocker Add-on For Firefox

Block Site is a website blocker Firefox add-on that can restrict access to specific websites as per custom schedule and can also redirect them.

Block Site Firefox add-on page

Download and install it from here.

enable Block Site to run in Firefox private windows

After it is installed, it will be visible as an icon next to the Firefox address bar.

Block Site add-on icon

You can block websites with two ways when using this add-on:

1. Directly go to the website address and then click on the Block Site icon.

manually block websites while surfing using Block Site add-on

There will be a pop-up asking confirmation to block the website.

Block Site default page when accessing blocked websites

2. The other way is to add the websites to be blocked using the configuration page of this add-on. To do that, right-click on the add-on icon and choose Manage Extension.

managing Block Site add-on

Then, click on the dots icon and select Options.

accessing Block Site options

Block Sites has a detailed configuration page from which not only you can add websites to be blocked, but also set a schedule for them. First set a master password from here. This password can be used to temporarily access blocked websites if needed and it can also be used to unlock the configuration page for making any additional changes.

Block Site configuration page

These settings have numbers next to them and the bottom of the page explains the use of each feature by referring to its corresponding number.

If you want to add a redirect from the blocked website, add it in the Redirect to text box. This is useful if you have a custom page that needs to be loaded every time a blocked website is loaded. A user message can also be added which will be displayed when the blocked website is accessed.

adding a redirect to blocked websites and entering custom user messages in Block Site

You can also allow temporary access to the blocked website in seconds by specifying it in seconds in the Allow access to the unblocked hostname field when they are unlocked with the master password. Other than that, you can also set a countdown timer after which the blocked website will be closed.

access limit for blocked websites in Block SiteThis timer will be visible in the Firefox tab whenever an attempt is made to access the blocked website.

countdown timer for blocked websites before tab closure using Block Site

To set a time and date schedule for blocked websites, set them in the Only block sites between settings.

setting a schedule for blocked websites using Block Site

Reverse mode is just the opposite, it will block all the websites except those that are added in the hostname field. Keep it turned off if you want to block only a few websites as this is a very restrictive measure.

To add different websites to block, add their URLs in Block a new hostname field. By default, Block Site will block both the HTTP and HTTPS instances of website names.

adding websites to be blocked in Block Site

However even after adding if the sites are accessible, add their full URLs in the hostname field (e.g:

To remove them from the blocked list, click on the Remove button next to them.

For a more granular approach, Block Site also supports regular expressions. So suppose if you want to block all the websites whose URLs have occurrences of specific words or terms, you can use the prefix R: and add them. So for example, to block all HTTPS URLs that contain the term Facebook, the regular expression will be R:://https*://.*\.facebook\.com.

choosing a regular expression for websites to be blocked using Block Site

If there are many websites to be blocked, you can add them in a text file using the below format.

text file format for adding a list of websites to be blocked using Block Site

Then import this file by clicking on Import (TXT File).

importing text file for a list of blocked websites

Also, all the settings can be saved as a JSON file by exporting them. Do this by clicking Export (JSON File).

exporting and importing Block Site settings

Once the settings are in effect, access to specific websites will be restricted as per the configured rules.

websites blocked using the Block Site rules that are configured

You can change the default dark theme of the lockdown page by clicking on the top right of the page.

light mode for default block page in Block Site

Also, the website can be temporarily accessed with the master password if needed.

temporarily allowing blocked website by using the master password in Block Site
Happy surfing.

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