# Opsidian

A Markdown notebook for Mac and iPhone. Your notes are plain files in a folder you choose, and they sync through a machine you own: your Mac, a small server, or anything on your Tailscale network. There is no account and no sync service.

- [Download for Mac](https://github.com/ferran9908/opsidian/releases/latest/download/Opsidian-arm64.dmg)
- [Intel Mac version](https://github.com/ferran9908/opsidian/releases/latest/download/Opsidian-x64.dmg)

macOS 13 or later, on Apple silicon or Intel. The iPhone app is coming to TestFlight soon.

## Write on your Mac

1. Download Opsidian, open the disk image and drag Opsidian into Applications.
2. Open it and create a notebook. It is a folder of Markdown files, so other editors can open it too.
3. Write. Everything saves as you type and works without a network.

## Keep your devices in step

1. One machine hosts your notebooks, and every device syncs through it. The simplest host is the Mac you write on: open Settings, choose Turn on hosting, then Invite a device.
2. On the iPhone, open Opsidian, choose Connect, and scan the invitation. On another Mac, choose Connect to a notebook and type the address and code.
3. To sync away from home, install Tailscale on the host and on each device and sign in to the same account.

## Host on a server instead

A host that is always on can be a Mac mini or a Linux server with Node 24. It runs in the background and starts again after a crash or a restart. It only listens on the machine's Tailscale address, because it has no sign-in of its own.

```sh
# Start the host
npx opsidian host start

# Invite a device (prints a QR code)
npx opsidian host invite "Personal"

# See how it is doing
npx opsidian host status
```

## Details

Opsidian collects nothing. There is no analytics and no account, and your notes only ever go to the host you choose.

The code is open source, under MIT or Apache 2.0. Source: https://github.com/ferran9908/opsidian