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Introduction to Nostr

Nostr (Notes and Other Stuff Transmitted by Relays) is a simple, open protocol that enables truly censorship-resistant and decentralized communication.

What is Nostr?​

Nostr is not an app or a service—it's a protocol. Think of it like email or HTTP: a standard way for different software to communicate. Anyone can build apps that use Nostr, and all these apps can interoperate.

At its core, Nostr is remarkably simple:

  • Clients are apps that users interact with (mobile apps, web apps, desktop apps)
  • Relays are servers that store and forward messages
  • Events are signed JSON messages that contain all data

Nostr Network

Why Nostr?​

Censorship Resistance​

There's no central authority that can ban you or delete your content. You can always publish to relays that will accept your messages.

Identity Ownership​

Your identity is a cryptographic keypair that you control. No company owns your account. You can use the same identity across all Nostr apps.

Data Portability​

Your data isn't locked in a single platform. Switch apps anytime—your followers, posts, and social graph come with you.

Simplicity​

The core protocol is intentionally minimal. A basic client can be built in a few hundred lines of code.

Key Concepts​

Keys​

Your identity in Nostr is a secp256k1 keypair:

  • Private key (nsec): Secret key for signing. Never share this.
  • Public key (npub): Your public identity. Share freely.
// Example: A Nostr keypair
{
  privateKey: "nsec1...", // Keep secret!
  publicKey: "npub1..."   // Your public identity
}

Events​

Everything in Nostr is an event—a signed JSON object:

{
  "id": "32-bytes hex string",
  "pubkey": "32-bytes hex string",
  "created_at": 1234567890,
  "kind": 1,
  "tags": [],
  "content": "Hello, Nostr!",
  "sig": "64-bytes hex string"
}

Relays​

Relays are simple WebSocket servers that:

  • Accept events from clients
  • Store events (according to their policies)
  • Send events to clients that request them

You typically connect to multiple relays for redundancy.

Getting Started​

Ready to start building? Here's your path:

  1. How Nostr Works - Understand the architecture
  2. Keys and Signing - Learn about cryptographic identity
  3. Build Your First App - Create a working Nostr client

Community​

Next Steps​

Continue to How Nostr Works to understand the protocol architecture in detail.