What Is Nostr? A Plain-English Guide for People Who Just Want Private Messages

In short: Nostr is an open network for messages and posts. Instead of an account on a company’s server, you have a key pair on your own device, and your messages travel through independent servers called relays. No single company can lock you out, and any app that speaks Nostr can use the same identity.

If you have heard the word “Nostr” and assumed it was only for crypto people or social media fans, this guide is for you. We built amend on Nostr, so we have spent a lot of time explaining it to friends and family. Here is the version without jargon.

What does Nostr stand for?

Nostr stands for Notes and Other Stuff Transmitted by Relays. It is not an app and not a company. It is a protocol: a shared set of rules, like email, that many different apps can follow. It was first published in 2020 and is developed in the open by volunteers through documents called NIPs (Nostr Implementation Possibilities).

The three ideas you need

1. Keys instead of accounts

On Nostr you don’t sign up with a phone number or email. Your app creates a key pair on your device:

• A public key (it starts with npub1). This is your address. You share it like a username so people can find and message you.
• A secret key (it starts with nsec1). This proves you are you. Never share it with anyone, and keep a backup somewhere safe.

Because there is no company account, there is no “forgot password” button either. Whoever holds the secret key controls the identity. That is the main trade-off of Nostr, and it is why amend asks you to back up your key. We wrote more about this in Private Messenger Without a Phone Number.

2. Relays instead of one company’s servers

Relays are simple servers that receive messages and pass them on. Anyone can run one, and thousands of them are run by different people and organisations. Your app talks to several relays at once, so if one goes offline or blocks you, the others still work. You can change the list of relays you use at any time.

3. Many apps, one identity

The apps you use to read and send on Nostr are called clients. Because they all follow the same rules, the same key works in all of them. Someone using amend can exchange private messages with someone using another Nostr app that supports the same messaging standard, such as 0xchat or Amethyst.

Isn’t Nostr public, like Twitter?

Nostr became known for public social posts, and those are public by design. Private messages work differently. amend uses NIP-17, the Nostr standard for private messages: every message is encrypted on your phone, sealed, and then wrapped again with a one-time key. Relays only see an encrypted package, not who sent it or what it says. Read our NIP-17 explainer if you want the details.

To be honest about the limits: relays can still see your IP address, the recipient’s public key and the size of the encrypted data. If that matters to you, connect through a VPN or Tor.

Why we built amend on Nostr

• No phone number needed. Your identity is a key, not your SIM card.
• No single point of failure. If amend the project disappeared tomorrow, your identity and your contacts would still work in other Nostr apps.
• No company holding your messages. We don’t run a server that stores your chats, so there is nothing for us to sell or leak.

Quick glossary

npub	Your public key. Safe to share.
nsec	Your secret key. Never share it.
Relay	A server that passes messages along.
Client	An app that uses Nostr, like amend.
NIP	A document describing one part of the protocol.
NIP-17	The standard for encrypted private messages.

Want to try it? amend is in closed testing on Google Play, and the public launch is coming soon. See the Get amend page for the latest status, or read how to choose a private messenger.