How does uBlacklist filter search results?

uBlacklist filters search results by matching each result against rules you provide, then either removing it from the page or marking it visually. You can block a site by its URL (using match patterns or regular expressions), block it by its title (using regular expressions), or highlight sites you prefer. It works on Google Search plus Bing, Brave, DuckDuckGo, Ecosia, SearXNG, Startpage.com, Yahoo! JAPAN, and Yandex, and is available for Chrome, Firefox, Edge, and Safari.

The three filtering mechanisms

1. Blocking by URL

This is the most common approach. You give uBlacklist a pattern that describes the result's URL, and any matching result is removed from the page.

Two pattern styles are supported:

• Match patterns — the same syntax browser extensions use for permissions. For example, *://*.example.com/* blocks every page on example.com and its subdomains. This is the right choice when you want to block a whole site without thinking about individual pages.
• Regular expressions — for finer control. For example, a regex can target a path segment, a query parameter, or a subdomain pattern that match patterns can't express. Use this when you need to block only part of a site.

The practical difference: match patterns are readable and hard to get wrong; regular expressions are powerful but easy to over-match. If a regex is too broad, you'll remove results you actually wanted.

2. Blocking by title

Instead of looking at the URL, uBlacklist can match the result's title text with a regular expression. This is useful when the same unwanted content appears across many domains, or when a site rotates its domain but keeps the same title format. The trade-off is that titles change more often than domains, so title rules tend to need more maintenance.

3. Highlighting preferred sites

Rather than removing results, you can mark sites you trust so they stand out in the results list. This doesn't hide anything — it just makes the results you care about easier to spot. It's the right tool when your goal is prioritization rather than exclusion.

How the rules reach your browser

You have two ways to supply rules:

• Your own rules — entered directly in the extension.
• Subscribed public rulesets — maintained by others and pulled in automatically. This is where the "subscribe" in the product description comes from: you subscribe to a ruleset rather than writing every rule yourself.

Rulesets can be synchronized across devices through Google Drive, Dropbox, OneDrive, WebDAV, or browser sync, so the same filtering applies on every machine where you use the extension.

Choosing between blocking and highlighting

What to check before relying on it

• Pattern precision. A match pattern like *://*.example.com/* is broad by design. Confirm the scope before applying it, especially with regular expressions.
• Search engine coverage. The extension supports the engines listed above; if you use an engine outside that list, filtering won't apply there.
• Ruleset trust. Subscribed rulesets are maintained by third parties. Review what a ruleset blocks before subscribing, since you're delegating the filtering decisions to it.
• Sync setup. Cross-device consistency depends on configuring one of the sync backends; without it, rules stay local to the browser where you entered them.

If your need is simply "stop seeing this site in search results," a URL match pattern is enough. If you need to suppress a class of results across domains, title regexes or a subscribed ruleset will save more effort. If you'd rather not hide anything, highlighting is the safer option.