MetaMask Legacy Web3 Firefox

MetaMask Legacy Web3

Adds MetaMask's legacy window.web3 API to your browser

Features & Capabilities

The MetaMask Legacy Web3 Chrome extension reinstates the deprecated window.web3 API previously provided by MetaMask. Although MetaMask stopped injecting window.web3 in December 2020 to boost security and performance, this change can disrupt older or unmaintained decentralized websites and applications (dApps).

By adding this extension alongside your MetaMask wallet, you regain compatibility with those legacy dApps without sacrificing the convenience of MetaMask. It ensures seamless interaction with blockchain sites that still rely on the legacy API, preserving accessibility to older Ethereum-based services without compromising security improvements.

User Growth & Download Statistics

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:
danfinlay
Firefox Add-ons Store
https://addons.mozilla.org/firefox/addon/metamask-legacy-web3/
Email:
su*****@metamask.io
Website:
https://support.metamask.io

User Reviews

User reviews for MetaMask Legacy Web3 are predominantly positive, highlighting it as a great application and expressing satisfaction with its overall performance. There were no consistent negative points mentioned across multiple reviews.
Pros
  • Users generally view the add-on positively and appreciate its functionality.
  • Described as a great application by multiple users.
Cons
Recent reviews
by Fi*****, 2025-07-12

by Fi*****, 2025-06-30

by Fi*****, 2025-06-25
View all user reviews ›

Is MetaMask Legacy Web3 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.

MetaMask Legacy Web3 requires a few sensitive permissions. 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.
  • High ******* ******* **** *** ****** ***** *** ***** ** ******* **** ********* ********* ** * *********** *****
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.

MetaMask Legacy Web3 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.
  • Low **** ********* *** ******* **** **** * ****** **** ***** ******** *** **** ****** ** ** ****** *** *****
  • Low **** ********* *** ***** **** **** * ****** **** ***** ********** *** **** ****** ** ** ****** *** *****
  • Good **** ********* *** **** **** *******
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Best MetaMask Legacy Web3 Alternatives

Here are some Firefox add-ons that are similar to MetaMask Legacy Web3: