$ cat ~/blog/on-device-legal-ai.md
Why Legal AI Should Run on Your Machine, Not Someone Else's Cloud
Sensitive testimony shouldn't be uploaded to a vendor just to be useful. The case for on-device legal AI — privacy, continuity, and cost — and where the line actually is.
There’s a default in modern software that the legal field should push back on harder than it does: the assumption that to be useful, your data has to leave the building. Upload the transcript. Send the recording to the API. Trust the dashboard.
For most software, fine. For legal work — depositions, medical records, privileged material — that default is backwards.
The case for on-device
Privacy is the obvious one. Every cloud hop is another copy of sensitive testimony on infrastructure you don’t control, governed by terms you didn’t write. “We don’t train on your data” is a policy, not a guarantee, and it can change with a press release.
Continuity is the underrated one. A tool that runs on your machine doesn’t go dark because a provider has an outage, gets acquired, or has its model recalled. (I wrote about that last one separately — it’s a real risk now, not a hypothetical.) Local tools keep working when the network — or the vendor — doesn’t.
Cost is the quiet one. Per-seat, per-document, per-minute pricing adds up fast across a firm. A lot of legal AI work — format conversion, search, first-pass extraction — doesn’t need a frontier model in a data center. It needs to run where the file already is.
Where the line actually is
On-device isn’t a religion. Some things genuinely need a big model you can’t run locally yet, and that’s fine — use it, with the safeguards from the reliability checklist. The point isn’t “never use the cloud.” It’s “don’t send your most sensitive material across the wire by default, for tasks that never required it.”
It’s why DepoAudio converts court recordings entirely on your machine — the audio is testimony, and testimony shouldn’t need a round trip to be playable. The more of your pipeline runs on infrastructure you control, the less any single vendor’s bad week is your problem.
Ask of any legal AI tool: where does my data go, and what happens to my workflow if that destination disappears? If the honest answer makes you uneasy, that’s the tool telling you something.
Curious how far on-device can actually go for legal work in 2026 — I’m building toward an answer.