CheerpJ Applet Runner

CheerpJ Applet Runner

Run Java applets without installing Java

CheerpJ Applet Runner promo image
What is CheerpJ Applet Runner?

CheerpJ Applet Runner is an Edge add-on by Leaning Technologies. This add-on has 26,521 weekly active users and a good user rating of 4.00. The latest version, 10.6, was updated 2 months ago.

Stats date:
Rating: 4.00 (12)
Version: 10.6 (Last updated: 2023-01-31)
Creation date: 2021-09-06
Manifest version: 3
  • scripting
  • activeTab
Size: 81.60M
Risk impact: Very low risk impact
Risk likelihood: Moderate risk likelihood
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Other platforms

CheerpJ Applet Runner
CheerpJ Applet Runner (v10.6)
194 97,833
Not available on Firefox
CheerpJ Applet Runner - Run Java applets without installing Java

With the CheerpJ Applet Runner extension, you can run legacy Java Applets on modern browsers without a Java plugin or a local installation of Java.

Using The CheerpJ Applet Runner is simple. Install the extension, visit your Applet-based website, and enable the extension by clicking on its icon on the upper right corner of your browser!

This extension works by 'converting' the Java Applet to WebAssembly and JavaScript on the fly. It is private and secure, runs fully client-side (i.e. it does not contact any server), and does not collect any data or analytics at all. All your data, as well as your application are kept within the boundaries of your browser.

This extension, developed by Leaning Technologies, is based on CheerpJ, a professional Java to HTML5 compiler. More information on CheerpJ are available at

This software is free to use for non-commercial purposes on public-network Applets. For any other use, such as internal network applets, or if you are a company or public-sector organisation and would like to licence CheerpJ, please get in touch with
Risk impact

CheerpJ Applet Runner is safe to use. It does not request any sensitive permissions.

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, bypass your security settings, and access your personal data. High risk impact extensions are not necessarily malicious. However, if they do turn malicious, they can be very harmful.

Risk likelihood

CheerpJ Applet Runner is probably trust-worthy. Prefer other publishers if available. Exercise caution when installing this add-on.

Risk likelihood measures the probability that an Edge add-on may turn malicious. This is determined by the publisher and the Edge add-on reputation on Edge Add-on Store, the amount of time the Edge add-on has been around, and other signals about the Edge 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 an Edge add-on, especially ones with higher risk impact and/or higher risk likelihood.

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User reviews
I wish we didn't have to click on the icon for every page we open. For the life of me I cannot understand why it has other options in the "Can open and change (etc)" yet only the "On click" can be chosen from those options. Other options are grayed out. Kind of defeats the purpose for having options in the first place. Nice to be able to view applets again, for sure, but this click stuff is a nuisance.
by Bill, 2022-12-22

its unable to launch java applet on my Edge. Useless add on.
by Rashid, 2022-10-13

Única solução para ainda conseguir rodar sites como o conectividade social da Caixa, utilizando o modo compatibilidade com o Internet Explorer do Edge. Obrigado!
by Jairo, 2022-07-25
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Promo images
CheerpJ Applet Runner marquee promo image
Marquee promo image