Block ads. Stop trackers. Spot scams.

Mammoth Blocker is a free browser extension that stops ads, trackers, fingerprinting and scam networks before they load — and checks any page for scam signs with one click. Everything runs on your device.

Get Mammoth — it's free See features

No account No data collected Open source

Works on

Chrome

Firefox

Edge

Brave

Opera

291

blocking rules built in

categories you control

bytes of your data collected

free, forever

Why Mammoth

Everything you need for a cleaner, safer web

One small extension. No settings you have to learn. Turn it on and browse.

Faster pages

Ads and trackers are stopped before they download, so pages load quicker and use less data.

Stop trackers

Blocks analytics beacons, session recorders and data brokers that follow you from site to site.

Anti-fingerprinting

Stops scripts built to identify your exact device, even when you clear cookies.

Scam check New

One click checks the page for fake virus alerts, gift-card demands and fake login forms.

Scam networks

Blocks pop-under and push-bait networks known for deceptive and harmful ads.

No cryptomining

Stops hidden scripts that use your computer to mine coins and drain your battery.

Fewer pop-ups

Optional: hide cookie banners and "allow notifications?" nags with one switch.

Pause per site

Need a site to work as-is? Pause Mammoth there with one click. The page reloads by itself.

Your own blocklist

Add any domain you never want to load again. It's blocked everywhere, on top of the built-in lists.

See what was blocked

The popup shows how many requests were stopped on each page, and exactly who tried.

Backup & restore

Export your settings to a simple file and bring them to another computer in seconds.

No account, ever

No sign-up, no email, no cloud. Your settings live only in your browser.

New in 2.1

Not sure about a page? Ask Mammoth.

Open the Mammoth popup and click Check this page for scam signs. In a second you get a clear answer in plain words.

Spots fake "your computer is infected" warnings and fake support phone numbers.
Warns about gift-card payments, seed-phrase requests and "act now" pressure.
Flags unsafe login forms and look-alike site names.
In Chrome, it can also ask the browser's built-in on-device AI for a second opinion.
Only runs when you click. The page never leaves your computer.

Get Mammoth

Page check

http://secure-pc-help-alert.example/warning

This looks like a scam

Says your device is infected. Websites can't know that.
Pushes you to call a "support" phone number.
Uses time pressure ("act now").

Checked on your device. Nothing was sent anywhere.

How it works

Up and running in three steps

Add it to your browser

One click from your browser's store. No account and no setup.

Browse like normal

Mammoth hands your browser a list of junk sites. The browser blocks them before they load.

Stay in control

See what was blocked, pause any site, check pages for scams, and change any setting.

Open lists

See exactly what Mammoth blocks

No secret lists and no paid exceptions. Every domain is right here. Pick a category.

Try it

Does Mammoth block this site?

Type a domain or paste a link. The check runs in this page — nothing is sent anywhere.

Try:

The difference

Built to be simple and honest

What you get	Mammoth Blocker	Many other blockers
Free for everyone	Yes	Often with paid tiers
Paid "acceptable ads" allowed through	Never	Sometimes, by default
Account or email needed	No	For some features
Collects usage data	No, none	Varies
Scam check for any page	Yes, on your device	Rarely
Full block lists visible to you	Yes, on this page	Varies
Open source	Yes	Varies

Mammoth uses built-in lists rather than huge downloaded filter lists, so it's light and easy to understand. Some sites may still show ads that come from the site itself.

Install

Get Mammoth for your browser

Pick your browser below.

Help

Frequently asked questions

Is Mammoth Blocker really free?

Yes. Every feature is free for everyone, and it will stay that way. There is no premium version. If you want to help, you can support it on Ko-fi, but nothing is locked behind it.

Does Mammoth collect any of my data?

No. Mammoth has no server, no account system and no analytics. Your settings and counts stay in your browser. Read the privacy policy for the details.

How is Mammoth different from other ad blockers?

Mammoth is small, simple and open. It never lets paid ads through, it shows you every domain it blocks, and it adds a scam check that runs on your device.

Which browsers does it work on?

Chrome, Microsoft Edge, Brave, Opera, Vivaldi and other Chrome-based browsers, plus Firefox (version 121 or newer) on desktop.

How does the scam check work?

When you click the button, Mammoth reads the page you're on and looks for common tricks with built-in rules. In Chrome, if your computer supports it, it also asks the browser's own on-device AI for a second opinion. The AI can add a warning but never remove one. Nothing is sent anywhere.

A website looks broken. What do I do?

Open the Mammoth popup and switch it off for that site. The page reloads and works like normal. You can also report the site so we can fix it for everyone.

Will it block ads on YouTube and social media?

Mammoth blocks known ad and tracking networks everywhere, including social pixels. Some big sites serve ads from their own servers, and those can't always be blocked without breaking the site.

Why is the "Annoyances" list off by default?

It hides cookie banners and notification nags. That's great, but it can change how some pages look, so you decide. One switch in Options turns it on.

Why does it ask for an extra permission to count?

The popup shows what was blocked on the current page without any extra permission. A running total and a live number on the toolbar icon need one more browser permission, so that part is off until you turn it on.

Will Mammoth slow down my computer?

No. The browser does the blocking with its own built-in engine, and pages usually get faster because less junk downloads.

Can I use it on my phone?

Not yet. Mammoth is a desktop extension for now. Firefox for Android support is on the list.

How do I remove it?

Right-click the Mammoth icon in your toolbar and pick "Remove from Chrome" (or "Remove Extension" in Firefox). All its settings are deleted with it.