Sleipnir
by Sleipnir
What Sleipnir is
Sleipnir is a free web browser from a maker founded in 2002 and headquartered in Osaka, Japan. Sleipnir 6 is designed for Windows and Mac and uses the Blink engine. Tabs display page thumbnails, can be grouped by dragging, and may group related tabs automatically. TiledTab presents large thumbnails for surveying open pages. On Windows, right-button gestures can switch or close tabs, go back, reload, and restore closed tabs. Portal Field searches and opens pages from search results, bookmarks, history, and addresses. Built-in ad blocking is included, and Chrome extensions are supported on Windows. The Mac version currently does not support extensions, while its Mac App Store edition omits some basic features because of App Store restrictions. Sleipnir Mobile is available for iPhone and Android, with bookmark synchronization across supported devices. Recommended articles are generated locally, according to the maker. Windows and Mac plans are listed as free.
Who it suits
Sleipnir suits users who want visual tab organization, gesture navigation, ad blocking, and bookmark synchronization across desktop and mobile devices. Windows users can also use Chrome extensions.
What it does well
- Visual thumbnails and automatic tab grouping
- TiledTab surveys and organizes open tabs
- Windows mouse gestures handle common tab actions
- Built-in ad blocking is included
- Bookmarks synchronize across supported devices
What to know first
- Mac version does not support extensions
- Mac App Store edition omits some basic features
- Mac download is temporarily paused for macOS Tahoe 26
Plans
| Plan | Billed and limits | Price |
|---|---|---|
| Sleipnir 6 for Windows | Windows 10 / 11 | Free |
| Sleipnir for Mac | macOS 10.13 High Sierra or later · download temporarily paused due to issues on macOS Tahoe 26 | Free |
As fenrir-inc.com lists them, read 11 Oct 2026. The maker's own page has the final word.
Verdict
Sleipnir focuses on thumbnail-based tab management, gestures, and cross-device bookmarks. Windows offers Chrome extension support, while Mac users face the listed feature and download limitations.
Facts from Sleipnir's own pages
- Bookmarks
- Sleipnir can synchronize bookmarks with Sleipnir on iPhone, iPad, Android, and Windows. · fenrir-inc.com, 11 Oct 2026
- Browser engine
- chromium · fenrir-inc.com, 23 Sept 2026
- Built-in ad blocking
- Yes · fenrir-inc.com, 23 Sept 2026
- Compatibility
- The browser uses the Blink engine, which the maker says is also used by Google Chrome. · fenrir-inc.com, 11 Oct 2026
- Cross-device sync
- Yes · fenrir-inc.com, 23 Sept 2026
- Extensions
- Chrome extensions are supported on the Windows version; the Mac version currently does not support extensions. · fenrir-inc.com, 11 Oct 2026
- Extension support
- chrome_store · fenrir-inc.com, 23 Sept 2026
- Founded
- 2002 · fenrir-inc.com, 19 Oct 2026
- Free plan
- Yes · fenrir-inc.com, 23 Sept 2026
- Gestures
- On Windows, users can use right-button mouse gestures to switch or close tabs, go back, reload, and restore closed tabs. · fenrir-inc.com, 11 Oct 2026
- Headquarters
- Osaka, Japan · fenrir-inc.com, 19 Oct 2026
- Mac limitation
- The maker says the Mac App Store version omits some basic features because of App Store restrictions. · fenrir-inc.com, 11 Oct 2026
- Mobile versions
- Fenrir also offers Sleipnir Mobile for iPhone and Android, with finger gestures for browsing. · fenrir-inc.com, 11 Oct 2026
- Supported platforms
- both · fenrir-inc.com, 23 Sept 2026
- Privacy
- The maker says recommended articles are generated locally, so they do not raise privacy concerns. · fenrir-inc.com, 11 Oct 2026
- Product
- Sleipnir 6 is a web browser designed for Windows and Mac. · fenrir-inc.com, 11 Oct 2026
- Reading
- Sleipnir uses adjusted font rendering to make web text more beautiful and readable. · fenrir-inc.com, 11 Oct 2026
- Search and navigation
- The Portal Field searches and opens pages from search results, bookmarks, browsing history, and addresses. · fenrir-inc.com, 11 Oct 2026
- Security
- Fenrir's company security policy describes operating, monitoring, reviewing, maintaining, and continually improving its security management system. · fenrir-inc.com, 11 Oct 2026
- Support
- Fenrir directs visitors to its email form for inquiries and notes it may not be able to respond by phone. · fenrir-inc.com, 11 Oct 2026
- Tab navigation
- TiledTab displays large thumbnails of open tabs so users can survey and organize them. · fenrir-inc.com, 11 Oct 2026
- Tabs
- Tabs show page thumbnails, can be grouped by dragging, and related tabs can be grouped automatically. · fenrir-inc.com, 11 Oct 2026
Where Sleipnir stands on Freedom251
- Web browsers#89 of 154