CullKit
Every cloud photo service asks for the same thing: your library. Upload it, and we will help you organise it. For casual phone snapshots, that trade-off might feel fine. For a working photographer with terabytes of RAW files on a NAS or external drive, it is not a trade-off at all. It is a non-starter.
What cloud photo fatigue looks like
You already store your originals on hardware you control: a Synology NAS, an external SSD, a working folder on your Mac. You chose that setup for a reason. You want fast local access. You want no monthly upload queues. You want client files to stay client files, not training data for someone else’s model.
And yet, when you need to cull a shoot, every tool that promises speed also demands your library. Upload everything. Index everything. Store your metadata on a server you do not own. The convenience comes with a privacy cost that photographers are increasingly unwilling to pay.
CullKit does not want your photos
CullKit is a dedicated photo culling and rating app for iPhone, iPad, and Mac. It browses, rates, flags, tags, and organises. It does not edit, it does not develop, and it does not upload anything anywhere. Your photos never leave your device. There is no cloud component, no library sync, no account that stores your decisions on a server you do not control.
When you point CullKit at a folder on your NAS, your external SSD, or your Mac, it reads the files directly. The full-resolution previews render locally. Every swipe, every star rating, every reject flag is processed on the device in your hand. Nothing is sent to CullKit. There is nothing to send it to.
Your ratings live where your photos live
This is the part that matters for privacy beyond the promise. A cloud tool that stores your metadata on its own servers now knows your workflow. It knows which frames you kept, which you rejected, which you rated five stars. For a wedding photographer with client confidentiality obligations, or a photojournalist whose selects carry editorial weight, that metadata is part of the story. It belongs on your storage, not somebody else’s.
CullKit writes every rating, flag, colour label, and tag to XMP sidecar files stored alongside your RAW images. XMP is the open metadata standard that Lightroom, Capture One, and Darktable all read natively. Your sidecars are text files in your own folder structure. You can back them up, archive them, or delete them. You control the data because the data is a file on your drive.
Credentials that stay on your device
When you connect CullKit to a Synology Photos library or an SMB share, your login credentials are stored in the device Keychain, Apple’s hardware-backed secure storage. There is no intermediary server that holds your NAS password. There is no CullKit account that proxies your connection. The app talks directly to your storage over your local network, encrypted via your NAS’s own TLS or SMB authentication.
CullKit is an independent product. It is not affiliated with or endorsed by Synology Inc., Adobe (Lightroom), Capture One, or Darktable. Compatibility claims only.
Who is a local-only culling workflow for?
This architecture is not an afterthought. It is the foundation the app is built on, and it matters to a specific kind of photographer:
The self-hosting photographer. You run a Synology, QNAP, TrueNAS, or UGREEN NAS because you want to own your library. A cloud culling tool that insists on uploading your files before it can rate them defeats the purpose of owning a NAS.
The professional with confidentiality obligations. Wedding photographers, event photographers, and commercial shooters handle client files that should not leave a controlled environment. Client privacy is part of the service. A local-only culling tool keeps the entire workflow, from import to selects, inside your own infrastructure.
The privacy-minded creative. You do not need a specific reason. You simply believe your photo library is yours, and you do not want an app that treats it as a resource to be uploaded and analysed elsewhere.
The photographer who’s been burned before. Anyone who has watched a cloud service change its terms, hike its prices, or quietly start training models on user content tends to want their working files somewhere a policy update can’t reach. A local-only tool removes that risk entirely: there is no account, no server-side copy, and nothing for a future terms change to apply to.
Why we built CullKit this way
CullKit started as a solution to a personal problem: a growing RAW library on a NAS, and no fast way to rate it without dragging everything onto a laptop and into Lightroom first. The local-only architecture wasn’t a marketing angle bolted on afterwards — it was the obvious design once the goal was “rate the photos where they already live.” If the files never need to move, there’s no reason to upload them, and every reason not to. That principle shaped the whole app: connect directly, render locally, write metadata in place, and keep credentials in the device’s secure store. Privacy here is a consequence of the architecture, not a promise layered on top of it.
Fast culling, no compromise
Local-only does not mean slow. CullKit’s culling workflow is full-screen and gesture-driven on iPhone and iPad: swipe to keep or reject, tap to rate, configure swipe actions to match your workflow. On Mac, it is keyboard-driven: number keys to rate, P to pick, X to reject, arrow keys to navigate. Auto-advance keeps you moving; undo rewinds the last action; crash recovery picks up where you left off.
The app works with Synology Photos, any NAS share over SMB, local folders, and external SSDs. RAW and JPEG pairs are reviewed as a single frame. HEIC, video, and Live Photo all render. There is a built-in demo mode with sample data so you can try the full workflow before connecting any real library.
Does CullKit collect analytics or see my photos?
No. There is no telemetry that sends your image data or metadata off the device, and there is no CullKit account that holds your library or your decisions. The app has nothing to upload your photos to — there is no CullKit server that stores images. Your RAW files, your ratings, your folder structure, and your NAS credentials all stay within your own devices and storage.
Concretely, here is what never leaves your control:
- Your photos. Previews are rendered locally from the files on your NAS, SSD, or folder. Nothing is copied to a cloud bucket.
- Your ratings and tags. Written to XMP sidecars in your own folders, not to a remote database.
- Your NAS credentials. Stored in the device Keychain, Apple’s hardware-backed secure store. No intermediary server proxies your connection.
- Your workflow. Which frames you kept, rejected, or rated five stars stays between you and your storage.
For a wedding photographer with client confidentiality obligations, or a photojournalist whose selects carry editorial weight, that last point is not a nicety — it’s the difference between a tool you can use on client work and one you can’t.
How is local-only different from a “private” cloud app?
Plenty of cloud photo services advertise privacy. The distinction is architectural, not a policy promise. A cloud app can see your library because your library is on its servers; its privacy rests on what it promises to do with that access. A local-only app cannot see your library because the data never reaches it — there is no access to misuse, no breach surface on someone else’s infrastructure, no policy change that can retroactively expose your photos.
That difference shows up in practical ways too. Local-only means no upload queue before you can start (you cull a 1,200-frame shoot immediately, not after an overnight sync), no recurring storage fee on top of the NAS you already paid for, and no dependency on a service that might shut down and strand your workflow. You own the storage, you own the metadata, and you own the tool’s behaviour.
Related reading
- The Best Way to Rate Photos on a NAS — the local-only rating workflow applied to a NAS.
- Get Your Culls into Lightroom Without Re-Importing — how local XMP sidecars reach your editor without a cloud step.
- No NAS? Cull from Any Local Folder or External SSD — local culling with no network at all.
Getting started
CullKit runs on iPhone, iPad, and Mac. It is available exclusively on Apple platforms; there is no Android or Windows version. Browse is free. The Pro subscription (with a seven-day free trial, then monthly or yearly) unlocks culling, star ratings, colour labels, XMP metadata writing, move, and delete.
Download CullKit on the App Store or browse the library in free mode to see how it handles your files before committing to a trial.
CullKit is an independent product. It is not affiliated with or endorsed by Synology Inc., QNAP Technologies, TrueNAS / iXsystems, UGREEN Group, Adobe (Lightroom), Capture One, or Darktable. It connects to NAS devices via the standard SMB protocol, the same way any other SMB client does. Compatibility claims only.