Local Face Search vs Cloud Face APIs: When Offline Wins
Cloud face APIs are better at scale and worse at privacy. A local desktop index is the opposite. Here is an honest comparison — cost, accuracy, speed and what actually happens to your photos.
Published 2026-09-28 4 min read
- privacy
- comparison
- offline
If you want to find a person across your photos, you have two broad options: send your library to a service that indexes it for you, or keep the index on your own machine. Both work. They fail in completely different ways, and the right choice depends almost entirely on what is in your library and how much of it you are willing to move.
This comparison is written by the people who build the local option, so read it with that in mind — but the failure modes below are real, and they are the ones people discover after they have already uploaded everything.
The core difference
| Cloud face API | Local desktop index | |
|---|---|---|
| Where photos go | Uploaded to the provider | Never leave the machine |
| Where the index lives | Provider’s servers | Your disk (~/.snapbyface/) |
| Cost model | Per call or per month | One-time licence |
| Setup | API key, SDK, code | Install, point at folders |
| Scale | Millions of images | Limited by your disk and patience |
| Works offline | No | Yes |
| Typical user | Developer building a product | Person with a large personal library |
Where the cloud genuinely wins
Be honest about this: cloud APIs are the better engineering choice for some jobs.
- Scale beyond one machine. If you are indexing millions of images for a product, a local desktop tool is the wrong shape entirely.
- Managed infrastructure. No model files to ship, no hardware differences to handle.
- Broader face analysis. Providers offer age estimation, emotion detection, landmark data — features a focused search tool deliberately does not have.
If you are building a service, use an API. This article is not arguing with that.
Where local wins
Your photos do not become someone else’s asset
This is the whole argument, and it is not hypothetical. Uploading a personal library means the provider processes and stores face data derived from your family, your colleagues, and anyone else who wandered into frame. That data is subject to their retention policy, their breach risk, and their terms — not yours.
A local index inverts it: every step runs on your own computer. SnapByFace keeps everything it knows about your media — and its logs — in ~/.snapbyface/, and no image or video is uploaded. There is no account, so there is nothing synced anywhere.
No upload bottleneck
A few hundred gigabytes of footage does not upload quickly. Local indexing starts working immediately and does not depend on your upstream bandwidth — usually the slowest number in the whole setup.
Predictable cost
Cloud pricing scales with volume. A one-time licence does not. If you will re-search the same library for years, the maths stops being close.
It works on a plane, in a studio, on a locked-down network
Air-gapped and offline environments are not an edge case for some people — they are the working environment.
The honest trade-offs of going local
Local is not free. These are the costs:
- Your hardware does the work. Indexing uses your CPU. On a large library it is a background task you schedule, not something that finishes in seconds.
- You ship the models. SnapByFace is about 300 MB installed because the face models are bundled — no runtime download, but a bigger installer.
- Your backup is your problem. The index lives on your disk; if the disk dies, you re-index.
- No elastic scale. A desktop index handles a personal archive well and a data centre badly.
A middle path that usually is not
“Upload only the face crops” sounds like a compromise, but you have already sent the thing that matters — biometric data — and you now depend on the provider keeping that separate from everything else. Treat it as an upload, because that is what it is.
How to decide
Ask three questions:
- Would I be comfortable with this library sitting on someone else’s server? If the answer is anything but yes, go local.
- Am I building a product or solving my own problem? Product → API. Own problem → local tool.
- How often will I search this library again? Repeatedly → the one-time cost wins.
What SnapByFace does and does not do
To be precise about the local option:
- Does: index photos and video from your folders, match them against reference photos you supply, run entirely on your machine, export results to CSV.
- Does not: upload anything, require an account, rename or modify your files, or identify people you never added.
The only outbound data is an optional device statistics ping — machine code, app version, operating system, language, activation state and plan. No photos, no face data, no file paths, no search activity. It is on by default and can be switched off in Settings.