Open a Sketch File

People receive .sketch files in the same places they receive a PDF or a ZIP: a shared drive, an email from a freelancer, a handoff folder from an agency, a ticket that says the mock is attached. Opening it used to mean owning a Mac with a Sketch licence, or asking the sender to export a PNG and waiting. This page is the short path. You drop the file, you see the preview the file already contains, and you can download that picture. You do not create a Sketch account and you do not install a desktop app.

What you are opening is not a mystery binary. From Sketch 43 onward the app writes a zip. Unzip it and you find document.json, meta.json, one JSON file per page, and a preview PNG. This page does that unzip itself, checks those two JSON files are present, and refuses anything else so a random zip renamed to .sketch does not pretend to open. The app version from meta.json is shown next to the file name, which helps when someone asks which Sketch release saved the document.

Handoff is usually about reading, not editing. You want to know how many pages and artboards there are, what they are called, and which layers are hidden. The list under the preview is that inventory: page name, artboard names, then every layer with its type and visibility. A text layer can be copied out, which is useful when the only copy of a headline lives inside the design. This is a viewer. It does not move layers, change colours or save a new .sketch.

Keep the limits in mind before you promise a pixel match. The downloaded preview is Sketch's own image, so it is as faithful as the file. An artboard exported from here is drawn from rectangles, ovals and text only, and the page labels that drawing approximate. Bitmap images inside the file are named in the tree and are not painted onto that artboard PNG. Very large files, over 300 MB, are turned away so a phone tab does not run out of memory. Pre-43 files, and zips that are not Sketch documents, get a clear error.

A mock of an unreleased screen should not travel to a server just so you can look at it. Opening runs entirely in your browser: the zip library reads the bytes, the preview is the PNG that was already in the archive, and a download never leaves your device except as a file you choose to save. There is no share link and no account the file could be stored against.

Analytics on this page count anonymous events such as the tool being opened or a PNG being downloaded. They do not include the file name, the layer names, the text you copy, or the picture. Ads on the page do not receive the file either. If the browser blocks the clipboard, the page says so instead of pretending the copy worked.