OpenAnyFile
What is a .avifs file?
AVIF Image Sequence is an image format developed by Alliance for Open Media, first released in 2019. It is usually created by ffmpeg, Squoosh, animation exporters.
Animated AV1 frames — typically a fraction of the size of the same animation as GIF, with full colour and alpha.
File details
| Full name | AVIF Image Sequence |
|---|---|
| Category | Images |
| MIME type | image/avif-sequence |
| Signature (magic bytes) | .. 66 74 79 70 61 76 69 73 (ftypavis) |
| Developer | Alliance for Open Media |
| Introduced | 2019 |
| Opens with | Image viewer |
| Uploaded? | No — read locally in your browser |
How to open a .avifs file
OpenAnyFile routes .avifs files to its image viewer, which shows the full image, zoomable, with its pixel size.
- Drop your .avifs file on the box above, click it to choose the file, or paste it with Ctrl+V.
- The real format is detected from the file's first bytes — not just its name.
- The file opens in the image viewer.
- Use fullscreen for a closer look, check its checksums, or download it back unchanged.
What works — and what does not
Works
Viewing and inspecting: the full image, zoomable, with its pixel size. Size, type, signature and checksums are always shown.
Does not work
Editing and saving back. OpenAnyFile is a viewer, not an editor — for changes you still need the original app.
Is it safe to open a .avifs file online?
Here, yes — because nothing is uploaded. Most "online viewers" send your file to their server. OpenAnyFile reads it with your browser's File API and decodes it on your own device, so there is no copy anywhere else. You can check: open your browser's network tab while opening a file — no upload appears.
Questions about .avifs files
Can I open a .avifs file without installing software?
Yes. OpenAnyFile opens .avifs files in your browser using its image viewer. You get the full image, zoomable, with its pixel size, with nothing installed and no account.
How do I know a file is really a .avifs file?
Check its first bytes instead of its name. A genuine AVIFS file begins with .. 66 74 79 70 61 76 69 73 (ftypavis). OpenAnyFile shows the detected type, so a renamed file is easy to spot.
Is my .avifs file uploaded anywhere?
No. The file is read locally by your browser and never sent to a server — it even works offline once the page has loaded.
Does it work on phones?
Yes — on Android and iPhone, in any modern browser. You can also install OpenAnyFile as an app.
Related formats
Other formats from the same family:
Format facts checked and page updated on September 25, 2026.