Shimeji Browser Extension: What It Is, How It Works, and Is It Safe?

Shimeji is one of those browser extensions that sounds like it shouldn’t work as well as it does. The concept is simple: install the extension, pick an anime character, and watch it walk, climb, and generally cause mischief on whatever webpage you’re viewing. Over 2 million users have installed it, which puts it well beyond a niche curiosity.

However, Shimeji has also attracted suspicion. The extension requests permissions that seem disproportionate to what it does — and that’s a reasonable thing to question before installing any browser add-on. This article explains what Shimeji actually does, what permissions it needs and why, and whether it’s genuinely safe to use.

What is the Shimeji browser extension?

Shimeji is a browser extension originally created by Dutch developers as a purely entertainment-focused tool. It has no productivity features, doesn’t block ads, doesn’t modify search results, and doesn’t save passwords. Its sole purpose is to place small animated characters — typically from anime, games, or pop culture — onto your browser screen, where they move around independently as you browse.

The name comes from the original Shimeji-ee Japanese desktop pet application, which predates the browser extension and was popular in the early 2010s. The browser version brings that concept into Chrome, Edge, Firefox, and other Chromium-based browsers. Characters from series like Naruto, One Piece, and Demon Slayer are among the most commonly used, alongside custom creations shared by users on DeviantArt and Tumblr.

How does Shimeji work?

When you activate a Shimeji character, the extension injects a small animated sprite into whatever webpage you’re currently viewing. The character “lives” on the page — walking along the bottom edge, climbing text blocks and images, occasionally falling, and interacting with page elements. If you open a new tab, the character typically moves there too.

The animation is lightweight. The full extension is approximately 669 KB, which is smaller than most webpage images. Shimeji doesn’t run complex processes in the background when you’re not actively using a character, though the extension itself remains loaded in your browser.

Users can switch between different characters, and the extension has an active community that creates and shares custom Shimeji figures. The official developer’s site at shimejis.xyz hosts a library of characters and provides installation guidance.

Is the Shimeji browser extension safe?

The short answer is yes — the official Shimeji extension from its verified developer is safe to use. However, there are nuances worth understanding before you install anything.

The permissions issue

Shimeji requests permission to “read and change all your data on websites you visit.” That phrasing understandably makes people nervous. However, this is a standard requirement for any extension that modifies webpage content — which is exactly what Shimeji does. To place an animated character onto a webpage, the extension has to interact with that page’s structure. There’s no way to do this without read/write access to page content.

The critical question isn’t what permissions an extension requests, but what it actually does with those permissions. For reference, ad blockers and password managers request the same level of access. Understanding basic browser security principles helps you evaluate these requests more confidently.

What data does Shimeji collect?

According to the extension’s official developer, Shimeji does not collect your personal data, does not track your browsing activity, and does not transmit information to external servers. Character selections and settings are stored locally in your browser. Google’s Chrome Web Store policies, enforced through Chrome’s extension review process, provide an additional layer of oversight for extensions distributed through that platform.

Watch out for fake Shimeji extensions

This is the real safety concern. The official Shimeji extension is fine — but several unofficial clones use similar names and branding. Some of these, such as “Shimeji Custom Wallpapers,” have been identified as browser hijackers that modify your default search engine and track browsing history. The safest approach is to install exclusively from shimejis.xyz or by searching directly for “Shimeji” in your browser’s official extension store and verifying the developer name matches the official publisher. Good browser extension security testing always starts with verifying the source.

How to install Shimeji

Installation takes about 60 seconds and requires no technical knowledge. Here’s the process:

1. Open your browser and navigate to shimejis.xyz or open your browser’s extension store (Chrome Web Store for Chrome users).
2. Search for “Shimeji Browser Extension” and locate the listing from the verified official developer.
3. Click Add to Chrome (or the equivalent button for your browser) and confirm the installation when prompted.
4. Review the permissions request and click Add Extension to accept.
5. Once installed, click the Shimeji icon in your browser toolbar, select a character from the available options, and activate it on any webpage.

The extension is available for Chrome, Microsoft Edge, Opera, and most Chromium-based browsers. Firefox users can find a compatible version through the Firefox Add-ons marketplace.

Which websites does Shimeji support?

Shimeji works on the vast majority of websites — social media platforms, video sites like YouTube, forums, news sites, and most general-purpose webpages. The character interacts with the visual structure of each page, so the experience varies slightly depending on page layout.

A small number of sites are not supported: the Chrome Web Store itself, browser settings pages, and some heavily secured or sandboxed environments. These exceptions exist because browsers restrict extension access to certain protected pages by design. The developers continue to expand compatibility, but these restrictions are controlled by the browser, not Shimeji.

Frequently Asked Questions About the Shimeji Browser Extension

Is Shimeji a virus or malware?

No — the official Shimeji Browser Extension from shimejis.xyz is not a virus or malware. It’s a legitimate entertainment extension that has been reviewed and distributed through major browser extension stores. The caveat is that unofficial clones with similar names do exist, and some have been flagged as browser hijackers. Always install from the official developer’s verified listing to avoid counterfeit versions.

Does Shimeji steal personal data?

According to the official developer, Shimeji does not collect personal data, does not track your browsing history, and does not send information to external servers. Your character selections and settings are stored locally in your browser. The extension’s privacy policy on shimejis.xyz details exactly what is and isn’t collected, and Google’s Chrome Web Store policies provide additional accountability for listed extensions.

Why does Shimeji need permission to read website data?

Because that’s the only way any extension can place content on a webpage. To render an animated character on top of a website, Shimeji has to interact with the page’s structure — which requires read and modify access. This is the same permission level that ad blockers, dark mode extensions, and translation tools use. The permission itself is standard; what matters is what the extension actually does with it.

Can I use Shimeji on YouTube or Discord?

Yes — Shimeji works on both YouTube and Discord, as well as most social media platforms and general websites. It doesn’t work on a small number of protected pages, such as the Chrome Web Store itself or browser settings pages, because browsers restrict extension access to those areas by default.

How do I remove Shimeji from my browser?

Open your browser’s extension manager (in Chrome, go to chrome://extensions), find Shimeji in the list, and click Remove. This completely uninstalls the extension and removes all stored character data. If you only want to disable it temporarily without uninstalling, toggle the extension off in the same menu — your settings will be preserved when you re-enable it.