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What does "processed on device" really mean?
By Himanshu Ranjan · Updated 8 November 2026
It means the work happens on your own computer and the file is not sent to a company's server to be processed. It does not mean the app never touches the internet: licence checks, updates and usage counts may still go online. The question to ask is what leaves the machine, and you can test that yourself.
A plain definition
When an app processes a file on device, your computer's own processor reads the file, converts or edits it and saves the result. Nothing has to travel to another computer. Online tools work the opposite way: your file is uploaded, processed on the vendor's servers and sent back. That is why the FBI's warning about free online converters is about sites, not about apps running locally: the risk begins when a copy of the file leaves your control.
What it does not mean
On-device does not automatically mean zero network activity. An app can process every file locally and still check a licence, look for updates or send anonymous usage statistics. Those are separate from file contents, but a trustworthy vendor says exactly what they are.
FileDial's own policy is a useful example of how specific a claim can be. Every tool runs on the Mac and files are never uploaded, and all tools work with Wi-Fi off. What does go online is a licence check at activation and weekly, which sends the licence key (stored hashed), a hashed hardware id, the Mac's name and the app version. Optional anonymous usage counts say which tool ran, whether it worked and the app and macOS version, with an off switch in Settings › Privacy. File names, paths and contents are never sent.
How to test a claim yourself
You do not have to take any vendor's word for it. These checks work on any Mac app and take a few minutes. None of them proves a negative forever, but together they show whether a file is plausibly leaving the machine.
The simplest test is to turn Wi-Fi off and run the task. If it works, processing is local. A second check is to open Activity Monitor and look at its Network tab while the app runs, which shows data sent and received per process. A sudden multi-megabyte upload when you process a small file is a red flag.
- Turn Wi-Fi and Ethernet off in Control Center or System Settings.
- Run the tool on a test file and confirm it completes.
- Turn the network back on, open Activity Monitor, and select the Network tab.
- Process a file again and watch the app's sent bytes; they should stay near zero relative to the file size.
Signs a vendor means it
A real on-device claim usually comes with specifics: what runs locally, what goes online and why, and how to switch optional reporting off. Look for a published list of what the app sends, a working offline mode you can verify, and signing and notarization. Apple says software that is signed by a registered developer and notarized is checked for known malicious content before Gatekeeper lets it run, which is a baseline, not a guarantee of behavior. FileDial is signed with an Apple Developer ID and notarized by Apple.
Be cautious with vague wording such as secure cloud processing, files deleted after processing, or bank-grade encryption. Those describe an upload, not on-device handling.
- Does it work with the network off?
- Does the privacy page list exactly what is sent?
- Is optional telemetry off by default or easy to disable?
- Is the app signed and notarized?
- Does the vendor avoid the word cloud for core file processing?
Where on-device is not enough
Local processing removes the upload risk, not every risk. A stolen unlocked laptop exposes local files, so FileVault and a login password still matter. Files you send afterwards leave your control too, which is why metadata clean-up and careful sharing are part of the routine. For the full argument for local tools, see the guide on why offline file tools matter.
Questions to put to any vendor
Marketing language blurs the line, so ask plain questions and expect plain answers. Which operations happen on my computer and which on your servers? What does the app send when I process a file, in bytes and in kind? Is there a document that lists every network call? Can I turn off optional reporting, and is it off by default? What happens if I block the app in a firewall: does the core task still work?
Watch for phrases that sound local but describe an upload: processed securely in the cloud, files deleted after one hour, encrypted in transit. These can all be true of a web service that still receives a full copy of your file. A genuine on-device product says what leaves the machine, how little it is and why.
A useful distinction is between data about the app and data about your files. A licence check and anonymous usage counts concern the app. File names, paths and contents concern you. FileDial's published facts draw that line: the licence check sends the licence key (stored hashed), a hashed hardware id, the Mac's name and the app version, optional anonymous usage counts can be switched off in Settings › Privacy, and file names, paths and contents are never sent.
Also look at the website. Does it use third-party trackers on the page where you are reading the claim? FileDial's privacy page says exactly what its site counts, which cookies Google Analytics sets and for how long, and that ads features are off. A vendor that is careful about its own site is usually careful elsewhere. None of this is proof, but a pattern of specific, checkable statements is the best signal a buyer has.
Questions
Does on-device mean the app works without internet?
Usually for the core task, yes, but it depends on the app. Some features, such as downloading a model or loading a web page, need a connection. Ask the vendor which features need the internet, and test the specific task you care about with Wi-Fi turned off.
Is on-device always more private than cloud?
For the file itself, yes, because no copy leaves your machine. But overall privacy also depends on what the app logs and reports. Read the privacy policy for telemetry, licence checks and crash reports, and look for a switch to turn optional reporting off.
Can an app process locally and still upload my files later?
Technically yes, which is why the network test matters. Watch the app's sent bytes in Activity Monitor while it processes a file, and read what the vendor says it transmits. A vendor that lists its outbound traffic precisely, and keeps file names, paths and contents out of it, is easier to trust.
Is a browser tool that says it runs locally the same thing?
Some web tools do process files in your browser with local code. That can be genuine, but it is hard to verify without inspecting the page, and the page can change between visits. A downloaded, signed and notarized app that works with the network off is easier to audit.