Using Nostr

NOSTR Posting Skill

Using nostr-sdk library

Source: https://github.com/besoeasy/nostr-sdk

Overview

Post messages, send encrypted DMs, and interact with the Nostr decentralized social protocol using minimal direct exports from the nostr-sdk module.

Installation:

npm install nostr-sdk

Key Concepts:

• nsec: Private key in bech32 format (starts with nsec1)
• npub: Public key in bech32 format (starts with npub1)
• Relays: WebSocket servers that propagate Nostr events
• Events: Signed JSON objects representing posts, DMs, etc.
• POW: Proof of Work (mining) to reduce spam

Default Relays:

• wss://relay.damus.io
• wss://nos.lol
• wss://relay.snort.social
• wss://nostr-pub.wellorder.net
• wss://nostr.oxtr.dev
• And 9+ more for maximum reach

Skills

post_public_note

Post a public text note to Nostr.

Usage:

const { posttoNostr } = require("nostr-sdk");

const result = await posttoNostr("Hello Nostr! #introduction", {
  nsec: "nsec1...your-private-key",
  tags: [],
  relays: null,
  powDifficulty: 4
});
console.log(result);

Parameters:

• message: Text content to post
• tags: Optional array of tags (e.g., [['t', 'topic']])
• relays: Optional custom relay list (uses defaults if null)
• powDifficulty: Proof of work difficulty (default: 4, 0 to disable)

Auto-extracted Tags:

• Hashtags: #nostr → ["t", "nostr"]
• Mentions: @npub1... → ["p", <pubkey>]
• Links: URLs automatically preserved
• Notes: note1... references → ["e", <event-id>]

Response:

{
  success: true,
  eventId: "abc123...",
  published: 12,      // Successfully published to 12 relays
  failed: 2,          // Failed on 2 relays
  totalRelays: 14,
  powDifficulty: 4,
  errors: []
}

When to use:

• User wants to post a public message
• Sharing content with hashtags
• Broadcasting announcements

reply_to_post

Reply to an existing Nostr post.

Usage:

const { replyToPost } = require("nostr-sdk");

const result = await replyToPost(
  "note1...event-id",           // Event ID (note or hex format)
  "Great post! @npub1...author", // Reply message
  "npub1...author-pubkey",      // Author's public key
  [],                           // Additional tags
  null,                         // Use default relays
  4                             // POW difficulty
);

When to use:

• Responding to a specific post
• Thread conversations
• Engaging with content

send_encrypted_dm (NIP-4)

Send encrypted direct message using legacy NIP-4 standard.

Usage:

const { sendmessage } = require("nostr-sdk");

const result = await sendmessage(
  "npub1...recipient",    // Recipient's public key
  "Secret message here",  // Message content
  { nsec: "nsec1...your-private-key" }
);

When to use:

• Compatibility with older Nostr clients
• Basic encrypted messaging
• Wide client support

Limitations:

• Sender/recipient metadata visible
• Older encryption (NIP-04)

send_encrypted_dm_modern (NIP-17)

Send gift-wrapped encrypted message using NIP-17 (recommended).

Usage:

const { sendMessageNIP17 } = require("nostr-sdk");

const result = await sendMessageNIP17(
  "npub1...recipient",    // Recipient's public key
  "Private message!",     // Message content
  { nsec: "nsec1...your-private-key" }
);

Benefits:

• Sealed sender (hides who sent the message)
• Better metadata protection
• Modern NIP-44 encryption
• Ephemeral keys for each message

When to use:

• Maximum privacy needed
• Modern applications
• Hiding sender identity

receive_messages (NIP-4)

Listen for incoming direct messages.

Usage:

const { getmessage } = require("nostr-sdk");

const unsubscribe = getmessage((message) => {
  console.log("From:", message.senderNpub);
  console.log("Message:", message.content);
  console.log("Time:", new Date(message.timestamp * 1000));
}, {
  nsec: "nsec1...your-private-key",
  since: Math.floor(Date.now() / 1000) - 3600  // Last hour
});

// Stop listening:
// unsubscribe();

Message Object:

{
  id: "event-id",
  sender: "hex-pubkey",
  senderNpub: "npub1...",
  content: "decrypted message",
  timestamp: 1234567890,
  event: { /* full event */ }
}

When to use:

• Building a chat bot
• Receiving DMs
• Monitoring for messages

receive_messages_modern (NIP-17)

Listen for incoming NIP-17 gift-wrapped messages.

Usage:

const { getMessageNIP17 } = require("nostr-sdk");

const unsubscribe = getMessageNIP17((message) => {
  console.log("From:", message.senderNpub);
  console.log("Content:", message.content);
  console.log("Wrapped ID:", message.wrappedEventId);
}, {
  nsec: "nsec1...your-private-key",
  since: Math.floor(Date.now() / 1000) - 300  // Last 5 minutes
});

// Stop listening:
// unsubscribe();

When to use:

• Receiving modern private messages
• Maximum privacy for incoming DMs
• Supporting NIP-17 protocol

get_global_feed

Fetch recent posts from the global Nostr feed.

Usage:

const { getGlobalFeed } = require("nostr-sdk");

const events = await getGlobalFeed({
  limit: 50,                                    // Max 50 posts
  since: Math.floor(Date.now() / 1000) - 3600, // Last hour
  until: null,                                  // Up to now
  kinds: [1],                                   // Text notes only
  authors: null,                                // All authors
  relays: null                                  // Use defaults
});

events.forEach(event => {
  console.log("Author:", event.authorNpub);
  console.log("Content:", event.content);
  console.log("Note ID:", event.noteId);
  console.log("Posted:", event.createdAtDate);
});

When to use:

• Building a feed reader
• Monitoring public posts
• Trending content analysis

generate_keys

Generate new Nostr key pair.

Usage:

const { generateNewKey } = require("nostr-sdk");

const keys = generateNewKey();
console.log(keys);
// {
//   privateKey: "hex-private-key",
//   publicKey: "hex-public-key",
//   nsec: "nsec1...",
//   npub: "npub1..."
// }

Quick Generate:

const { generateRandomNsec } = require("nostr-sdk");
const nsec = generateRandomNsec();
console.log(nsec); // nsec1...

convert_keys

Convert between key formats.

Usage:

const { nsecToPublic } = require("nostr-sdk");

const publicInfo = nsecToPublic("nsec1...your-key");
console.log(publicInfo);
// {
//   publicKey: "hex-public-key",
//   npub: "npub1..."
// }

Quick Start Examples

Example 1: Post a Message

const { posttoNostr } = require("nostr-sdk");

async function postHello() {
  const result = await posttoNostr("Hello from my bot! #nostr #automation", {
    nsec: "nsec1...your-private-key"
  });
  
  console.log("Posted:", result.eventId);
}

postHello();

Example 2: Send Private DM

const { sendMessageNIP17 } = require("nostr-sdk");

async function sendPrivateMessage() {
  const result = await sendMessageNIP17(
    "npub1...recipient",
    "This is a secret message!",
    { nsec: "nsec1...your-private-key" }
  );
  
  console.log("Sent:", result.success ? "Yes" : "No");
}

sendPrivateMessage();

Example 3: Listen for DMs

const { getMessageNIP17 } = require("nostr-sdk");

console.log("Listening for messages...");

const unsubscribe = getMessageNIP17((msg) => {
  console.log(`Message from ${msg.senderNpub}: ${msg.content}`);
}, {
  nsec: "nsec1...your-private-key"
});

// Keep running or call unsubscribe() to stop

Example 4: Quick Post (No Setup)

const { posttoNostr } = require("nostr-sdk");

// Auto-generates keys if not provided
const result = await posttoNostr("Quick post!", {
  nsec: "nsec1...your-key"  // Optional - generates new if omitted
});

Decision Tree

User wants to post to Nostr?
├─ Is it a public post?
│  ├─ Is it a reply to another post?
│  │  ├─ YES → Use replyToPost()
│  │  └─ NO → Use posttoNostr()
│  └─ Need spam protection?
│     ├─ YES → Set powDifficulty to 4+
│     └─ NO → Set powDifficulty to 0
│
├─ Is it a private message?
│  ├─ Maximum privacy needed?
│  │  ├─ YES → Use sendMessageNIP17()
│  │  └─ NO → Use sendmessage()
│  │
│  └─ Need to receive messages?
│     ├─ Use NIP-17 → getMessageNIP17()
│     └─ Use NIP-4 (legacy) → getmessage()
│
└─ Need to read posts?
   └─ Use getGlobalFeed()

Key Management

Security Best Practices:

• Never commit nsec keys to git
• Store keys in environment variables or secure vaults
• Generate new keys for testing
• Use different keys for different purposes

Environment Variables:

export NOSTR_NSEC="nsec1...your-private-key"

const { posttoNostr } = require("nostr-sdk");

await posttoNostr("Health check log", {
  nsec: process.env.NOSTR_NSEC
});

Error Handling

Common Errors:

• Private key not set → Provide nsec or generate keys
• Invalid nsec format → Check bech32 encoding
• Failed to post to Nostr → Check relay connections
• Failed to decrypt message → Wrong private key for recipient

Best Practice:

const { posttoNostr } = require("nostr-sdk");

try {
  const result = await posttoNostr("Hello", {
    nsec: process.env.NOSTR_NSEC
  });
  if (!result.success) {
    console.error("Failed to publish:", result.errors);
  }
} catch (error) {
  console.error("Error:", error.message);
}

Cleanup

Direct-export functions do not require a class instance, so there is no client cleanup step.

Resources

• Library: https://github.com/besoeasy/nostr-sdk
• Nostr Protocol: https://nostr.com
• NIPs (Nostr Implementation Possibilities): https://github.com/nostr-protocol/nips
• Key Tools:
  • https://nostrcheck.me (key converter)
  • https://snort.social (web client)
  • https://damus.io (iOS client)