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Nostr Signing Device Setup Guide

Nostr Signing Device Setup Guide

What is the NSD?

The LNbits Nostr Signing Device (NSD) serves as a secure alternative to storing private keys on a computer. Your private key is stored on the NSD and signs nostr messages on the device. The NSD works with a Chrome based browser and the Horse extension.

It is an affordable, off-the-shelf solution designed to work with LilyGo’s T-Display board, but can be adapted for any ESP32. It is currently for desktop use only. Android and iOS devices are not supported.

Join the LNbits community on Telegram for further information and support.

Setting Up the Nostr Signing Device (NSD) – User Guide

Follow these steps to set up your NSD.

  1. Make sure you are using a Chromium browser, such as Chromium, Google Chrome or Microsoft Edge.
  2. Install the CP210x USB to UART Bridge drivers from the Silicon Labs website:
  3. Connect the NSD to your computer.
  4. Open the installer webpage in Chrome/Chromium: a. Click “Flash”, connect the NSD, and select your device in the browser’s serial port connection popup. Choose “Erase.”

Uploading a Private Key

  1. Refresh the installer page in Chrome.
  2. Unplug the NSD, press the button on the device, and plug it back in to allow configuration.
  3. Click the “Config” toggle to open the configuration tool.
  4. Click “Connect” and select your device in the serial port selection window.
  5. Once connected, enter your private key into the text area below the connect button and click “Save to Device”. Private keys must currently be input as a hex string.
  6. Your device is now ready for use.

Using the NSD

  1. Install the Horse Chrome extension from:
  2. Connect the NSD to your computer via USB and visit a Nostr web app such as,, or
  3. Log in to the web app, and the Horse extension will automatically communicate with your NSD over Web Serial to log you in and sign your interactions.