How Sift works

Because Sift's job is to work through your whole library and remove things from it. Two parts of iOS's photo permission matter here:

• Full access, not limited access. Limited access means you hand an app a hand-picked set of photos. An organizer that can only see the photos you already chose has nothing to organize.
• Read and write, not read-only. Deleting photos and adding them to albums both require write access.

Sift has no network code of its own, so this access cannot go anywhere. See the privacy policy.

This is iOS, not Sift. Deleted photos move to Recently Deleted in the Photos app and stay there for 30 days before the space is actually reclaimed. That's a safety net iOS gives you, and no app can skip it.

To get the space back immediately, open Photos → Recently Deleted and empty it yourself. Sift links you straight there after a deletion.

Sift also labels reclaimed-space figures as estimates, because iOS provides no exact public API for a photo's size on disk.

It's still exactly where it was — in Recents and in All Photos — and it is now also in the album you chose. On iOS, adding a photo to an album is additive. There is no "move", and no app can make one.

What disappeared is the photo's place in Sift's review queue. Once you've dealt with a photo, Sift stops showing it to you, which is what makes a 40,000 photo backlog finite. Your actual library is untouched apart from the album you asked for.

Yes, at three different levels:

• Immediately — swipe right, tap the undo button, or tap the left edge of the screen. Every action Sift takes is reversible, including filing into an album and favouriting.
• Before you commit — photos you swipe up go to the delete pile, not to the bin. Open the pile and take anything back out of it right up until you tap the button to delete.
• After you commit — deleted photos sit in Recently Deleted in the Photos app for 30 days, and you can restore them from there.

iOS shows that confirmation itself, on behalf of every app that deletes photos, and it cannot be turned off.

That's exactly why Sift stages your deletions in a pile instead of deleting as you swipe: you get one prompt for the whole batch rather than one prompt per photo, which would make the app unusable.

Yes. Settings → Reset review history, which asks you to confirm first.

That clears Sift's record of which photos you've already handled, so every photo comes back into the queue. It does not touch your photo library: nothing is deleted, restored, un-filed or un-favourited. It only forgets what you'd already looked at.

Sift looks for two things:

• Burst frames. Photos your camera captured as one burst are duplicates by definition, and Sift groups them without any further analysis.
• Repeated attempts at the same shot. Photos taken within a few seconds of each other, at the same dimensions, are compared visually on-device and grouped when they're close enough.

Photos taken minutes apart are almost never near-duplicates, so Sift doesn't waste your battery comparing them. The comparison runs entirely on your device and pauses itself if the phone gets hot.

If you use iCloud Photos with "Optimize iPhone Storage", most of your full-size originals aren't on the device — they're in iCloud, and have to be fetched before they can be shown. Sift shows a download indicator while that happens.

Photos will be slow or unavailable when:

• you're offline or in Airplane Mode;
• you're on a slow or metered connection;
• iCloud is still syncing after a restore or a new device.

A photo that genuinely can't be fetched shows as a failed image rather than spinning forever, and you can skip past it.

Yes. Every gesture in Sift also has a button, so nothing is reachable only by swiping. Every control is labelled, and the app is checked automatically against unlabelled controls so that can't quietly regress.

Sift also supports every Dynamic Type size including the accessibility sizes, and honours Reduce Motion by cross-fading between photos instead of flinging cards.

Yes — Sift is a universal app and runs in any orientation on iPad. The photograph takes the extra width, while the controls stay grouped together so they're still reachable with a thumb.

With a keyboard attached:

• ← keep and move on
• → undo and step back
• ↑ add to the delete pile
• F favourite

Never. Sift organizes and deletes; it does not touch pixels. It has no editing features at all, and it never re-saves, re-compresses or re-encodes a photo.

The only changes Sift makes to your library are the ones you ask for: deleting a photo, adding it to an album, or marking it a favourite.

There's no catch. Sift has no subscription, no in-app purchases, no ads, no locked features and no limit on how many photos you can get through. There is no payment code in the app whatsoever.

It also has no account, no server and no analytics — so there's no data being collected in lieu of payment either.

No. Sift contains no networking code and makes no requests of its own. The only network activity that can occur is iOS fetching your own photos from your own iCloud library, which iOS performs directly.

Full details in the privacy policy.