OpenAnyFile
What is a .sketch file?
Sketch Document is a design format developed by Bohemian Coding, first released in 2010. It is usually created by Sketch for macOS.
Since Sketch 43 a ZIP of JSON page files plus previews/preview.png, a render of the first page.
File details
| Full name | Sketch Document |
|---|---|
| Category | Design files |
| MIME type | application/x-sketch |
| Signature (magic bytes) | 50 4B 03 04 (ZIP) |
| Developer | Bohemian Coding |
| Introduced | 2010 |
| Opens with | Package preview reader |
| Uploaded? | No — read locally in your browser |
How to open a .sketch file
OpenAnyFile routes .sketch files to its package preview reader, which shows the preview image stored in the package, plus every file inside.
- Drop your .sketch 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 package preview reader.
- 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 preview image stored in the package, plus every file inside. Size, type, signature and checksums are always shown.
Does not work
Editing layers or the raw data. You see the preview image stored in the file, not an editable document.
Is it safe to open a .sketch 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 .sketch files
Can I open a .sketch file without installing software?
Yes. OpenAnyFile opens .sketch files in your browser using its package preview reader. You get the preview image stored in the package, plus every file inside, with nothing installed and no account.
How do I know a file is really a .sketch file?
Check its first bytes instead of its name. A genuine SKETCH file begins with 50 4B 03 04 (ZIP). OpenAnyFile shows the detected type, so a renamed file is easy to spot.
Is my .sketch 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.