Security and transparency
Kern holds what you mean to do. Here is exactly who handles it, where it lives, which AI reads it, and how it’s protected. The legal version is the privacy policy.
Last updated 17 October 2026
Who does what
Kern is made by Mielmpie B.V. in Amsterdam, the Netherlands, and stands on a few companies you probably know.
| Company | What it does, and what it receives | Where |
|---|---|---|
| Supabase | Kern’s database, sign-in and server. It holds your tasks, keeps your devices in sync and sends the sign-in emails. | Ireland, EU |
| Anthropic | Runs Kern AI (below). It receives only what each feature needs. | United States |
| OpenAI | Turns voice recordings into text. It receives the recording and the names of your Spaces and labels, so they’re spelled right. | United States |
| Apple | Delivers the quiet pushes that tell your iPhone something changed. They carry no task and no text. | Worldwide |
| Sentry | Crash reports: where in Kern’s code something went wrong, and the app and system version, with no email address and not linked to your account. When the Mac app itself crashes, a report can include a snapshot of its memory, which Sentry reads to find the crash and then throws away. | Germany, EU |
| PostHog | Counts of moments like “task completed”, under a random number instead of your name. Never what your tasks say. | Germany, EU |
| Vercel | Serves this website. | Worldwide |
| Cloudflare | Runs the kern.do domain and forwards email sent to hi@kern.do. | Worldwide |
Kern AI
Kern AI is the name for everything Kern’s AI does for you: filing what you said into a task, editing a task by voice, writing the line under each open task, finding its buttons, researching it, reading a window you attached on the Mac, and keeping short descriptions of your Spaces and labels. It runs on Anthropic’s models.
- Each feature receives only what it needs: a task’s title and notes, the names and descriptions of your Spaces and labels, and for research a short “About you” sketch that makes results fit you. You can read and change that sketch in Settings › Research, or switch research off.
- Research can include web searches, run by Anthropic.
- Anthropic and OpenAI work for Kern under their terms for business customers, which don’t allow them to train their models on your data. They may keep it for a limited time under their own policies, for example to detect abuse.
Claude, when you connect it. Connecting Kern to Claude is your choice. Once connected, Claude can read and change everything in your Kern when you ask it to, and every change it makes is logged in the task’s Activity. What Claude reads is handled by Anthropic under your own agreement with them. You can disconnect Kern in Claude’s settings at any time.
Your voice
A recording stays on your iPhone or Mac until it has been turned into words, then it’s deleted. It goes to OpenAI for that one job and is never stored on Kern’s server. What you said is kept as text in the task, so you can always see where a task came from.
On the Mac
Quick Entry offers the window in front of you, but nothing is sent until you press Tab. Then Kern sends one picture of that window, with the app’s name and the window’s title, to Anthropic, whose AI reads what it’s about. The picture is never kept, on your Mac or on Kern’s server. In Settings you can switch the offer off, and name apps and websites it should never offer.
Where your tasks live
- On Kern’s server at Supabase in Ireland, in the EU, and on each of your devices. Every device keeps its own copy, so Kern works offline and syncs when it’s back.
- Supabase keeps daily backups, for 7 days.
- Kern’s server logs the time, your account’s number, your internet address and which function ran, never your tasks, and keeps those logs for 7 days.
How they’re protected
Walled off per account
The database itself keeps every account’s tasks apart, so one account can never read or change another’s.
No passwords
You sign in with a link sent to your email, so there’s no password to guess or leak.
Encrypted on the way and on disk
Everything travels over HTTPS, and Supabase encrypts the database and its backups.
Connected apps ask first
Claude connects through Kern’s own sign-in page, which shows which app is asking and where it will send you back, and warns when that isn’t Claude or Raycast.
Your sign-in stays on the device
On iPhone it’s kept in the Keychain, where iOS keeps your passwords.
Stored in the EU
Your tasks are stored and synced in Ireland; crash reports and usage counts stay in Germany.
Your controls
- Export My Data. One file with everything Kern’s server holds about you, readable by people and programs. On iPhone: Settings › Export My Data. On the Mac: File › Export My Data….
- Delete Account. In Settings, on iPhone or Mac. Your account and everything in it are deleted from Kern’s server straight away; backup copies expire within 7 days.
- Share usage statistics. A switch in Settings; when it’s off, Kern stops counting.
- Research. Settings › Research turns off research and the About you sketch.
- Claude. Disconnect Kern in Claude’s settings, any time.
What Kern never does
Kern shows no ads, doesn’t follow you across other apps or websites, and doesn’t sell or share your data with anyone beyond the companies above. This website sets no cookies, runs no analytics and loads no trackers.
Report a problem
Found a security problem, or have a question about your data? Write to hi@kern.do. Please give Kern a chance to fix a problem before you share it publicly.