KernDocumentation
Ten pages in three groups: using Kern, running a server, and building on it. If you don't know where to start, start with help.
Using Kern
Help
Installing Kern on Windows and Linux, the shortcuts worth knowing, where your data is kept, backups and export, the single switch that turns off everything online, Kern Cloud accounts and workspaces, what syncs and what never leaves your computer, share links, calendar feeds, and the problems people hit most often.
Start here if you are using Kern and something isn't clear.
Streams
A stream is an address your website or services send to. Each submission it accepts becomes a task, an inbox item or a GitHub issue in a space — a "Report a bug" button, a feedback form, a webhook or a failing CI job, dropped straight into your plan.
Covers sending submissions, responses and errors, authentication with a secret or a signature, spam and rate limits, field validation, templates, the delivery log, limits, worked examples and troubleshooting.
Running a server
Kern Cloud is optional, and you don't have to use the public one. The server is open source and the same code either way. Four pages cover it.
Self-hosting
The guide, from nothing to a server other people can safely use: choosing a shape, the installer, Docker and bare Node, a first-run checklist, TLS with Caddy or nginx, pointing Kern at it, who may sign up, mail, the security model, health checks, backups, upgrades and uninstalling.
Configuration
Every setting, grouped: addresses, database, secrets, registration, management, mail, limits and quotas. Which four are required, which can be changed without a restart, and four worked examples — one person on one machine, a team on a company domain, invitation-only, and tight on disk.
kernctl
The command reference: health and repairs, people, spaces, invitations, streams, live settings, notices, management tokens, pairing Kern Platform, backups and the service itself — plus where it finds its token, how to use it over an SSH tunnel, and what the exit codes mean.
Troubleshooting
Nineteen failures people actually hit, each with the symptom, why it happens, one command to confirm it, and what to change. Connections and TLS, the WebSocket mistake that breaks live collaboration quietly, mail, sign-up, management access, storage, restores and upgrades.
Building on Kern
Protocol
How things talk to a Kern server: the instance handshake and what the protocol number guarantees, how a client chooses a server and why that isn't an ordinary setting, signing in, how sync merges field-level patches, what the realtime socket carries, and the separate management API with its two gates. Read this before changing either side.
API reference
Every route a server serves: accounts and sessions, workspaces, members and invitations, sync, whiteboard images, streams, share links, calendar feeds, the realtime socket and the public endpoints.
Development
Building Kern from source: requirements and commands, the architecture, the data layer and migrations, backups and export, sync internals, privacy and permissions, passkeys and locked projects, releases and in-app updates, and how to work on the server.
Performance
Measured startup, idle memory, data operations on 5,000 tasks, bundle sizes and whiteboard frame times for a release build — with the method, and what wasn't measured.
Quick answers
| Question | Where |
|---|---|
| How do I install Kern? | Help → Installing |
| Where is my data kept? | Help → Where your data lives |
| How do I get my work out of Kern? | Help → Backups and export |
| How do I stop Kern going online at all? | Help → Turning off everything online |
| What actually syncs to the cloud? | Help → What syncs |
| How do I share a note or a project? | Help → Sharing and calendars |
| Why don't I see other people's cursors? | Troubleshooting → No live collaboration |
| How do I turn a form into tasks? | Streams → Quick start |
| How do I secure a stream? | Streams → Authentication |
| How do I run the server myself? | Self-hosting → Installing |
| What do I do straight after installing? | Self-hosting → First run |
| How do I put TLS in front of it? | Self-hosting → TLS |
| How do I point Kern at my own server? | Self-hosting → Pointing Kern at it |
| Who is allowed to sign up? | Self-hosting → Who may sign up |
| Nobody gets verification emails | Troubleshooting → Nobody gets codes |
| What does this setting do? | Configuration |
| What can kernctl do? | kernctl |
| How do I back the server up? | Self-hosting → Backups |
| How do I upgrade safely? | Self-hosting → Upgrading |
| Is a management token a way to read my notes? | Self-hosting → The security model |
Elsewhere
- Kern on GitHub — the desktop app: releases, issues and the source.
-
Kern-Cloud-Self-Host — the
server, Kern Platform and
kernctl. Apache 2.0. - Issues — bugs and ideas. Give the version from Settings → About.
- Privacy policy, terms of use and the contributor licence agreement.