NIP-11: Relay Information Document

Status: Final Author: scsibug Category: Relay

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Overview

NIP-11 defines how relays publish information about themselves. When you request a relay’s URL with an Accept: application/nostr+json header, it returns a JSON document describing:

• Relay name and description
• Supported NIPs
• Limitations (event size, rate limits, etc.)
• Payment requirements
• Contact information

This helps clients choose appropriate relays and adapt behavior based on relay capabilities.

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Why NIP-11 Matters

For Clients

• Feature detection - Know what NIPs a relay supports
• Error prevention - Avoid sending unsupported event kinds
• User information - Display relay details to users
• Optimization - Choose best relays for specific tasks

For Relay Operators

• Announce capabilities - Tell the world what you support
• Set expectations - Publish limitations upfront
• Professional presence - Provide contact info and policies

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How to Access

HTTP Request

curl -H "Accept: application/nostr+json" https://relay.example.com

Response

{
  "name": "Example Relay",
  "description": "A fast, reliable Nostr relay",
  "pubkey": "relay_operator_pubkey",
  "contact": "admin@example.com",
  "supported_nips": [1, 2, 4, 9, 11, 12, 15, 16, 20, 22, 33, 40],
  "software": "nostr-rs-relay",
  "version": "0.8.0",
  "limitation": {
    "max_message_length": 16384,
    "max_subscriptions": 20,
    "max_filters": 100,
    "max_limit": 5000,
    "max_subid_length": 100,
    "min_prefix": 4,
    "max_event_tags": 100,
    "max_content_length": 8196,
    "min_pow_difficulty": 0,
    "auth_required": false,
    "payment_required": false
  }
}

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Standard Fields

Basic Information

Field	Type	Description
name	string	Relay name
description	string	Description of the relay
pubkey	string	Admin’s public key
contact	string	Contact info (email, etc.)
software	string	Relay software name
version	string	Software version

Supported NIPs

{
  "supported_nips": [1, 2, 4, 9, 11, 15, 20, 22, 28, 33, 40, 42, 50]
}

This array lists all NIPs the relay implements.

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Limitations Object

The limitation field describes relay limits:

Size Limits

Field	Description
max_message_length	Maximum WebSocket message size (bytes)
max_content_length	Maximum event content length
max_event_tags	Maximum number of tags per event

Subscription Limits

Field	Description
max_subscriptions	Maximum concurrent subscriptions
max_filters	Maximum filters per subscription
max_limit	Maximum limit in filter queries
max_subid_length	Maximum subscription ID length

Other Limits

Field	Description
min_prefix	Minimum hex prefix for ID queries
min_pow_difficulty	Required proof-of-work difficulty
auth_required	Whether NIP-42 auth is required
payment_required	Whether payment is required

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Payment Information

Paid relays can include payment details:

{
  "payments_url": "https://relay.example.com/payments",
  "fees": {
    "admission": [{"amount": 1000, "unit": "sats"}],
    "subscription": [{"amount": 100, "unit": "sats", "period": 2592000}],
    "publication": [{"amount": 1, "unit": "sats"}]
  }
}

Fee Types

Type	Description
admission	One-time fee to use relay
subscription	Recurring fee (period in seconds)
publication	Fee per event published

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Icon and Branding

Relays can include visual branding:

{
  "icon": "https://relay.example.com/favicon.png"
}

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Checking Relay Info in Code

JavaScript Example

async function getRelayInfo(relayUrl) {
  const httpUrl = relayUrl.replace('wss://', 'https://').replace('ws://', 'http://');

  const response = await fetch(httpUrl, {
    headers: { 'Accept': 'application/nostr+json' }
  });

  if (!response.ok) throw new Error('Failed to fetch relay info');

  return await response.json();
}

// Usage
const info = await getRelayInfo('wss://relay.example.com');
console.log(`Relay: ${info.name}`);
console.log(`Supported NIPs: ${info.supported_nips.join(', ')}`);

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Client Usage

Feature Detection

const info = await getRelayInfo(relayUrl);

// Check if relay supports NIP-50 search
const supportsSearch = info.supported_nips?.includes(50);

// Check if auth is required
const needsAuth = info.limitation?.auth_required;

// Check message size limit
const maxSize = info.limitation?.max_content_length || 8196;

Relay Selection

Use NIP-11 to choose appropriate relays:

1. For search - Check supported_nips includes 50
2. For large content - Check max_content_length
3. For authentication - Check auth_required
4. For paid features - Check payment_required

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For Relay Operators

Implementing NIP-11

1. Create info document with your relay’s details
2. Serve at relay URL with Accept: application/nostr+json
3. Keep updated as capabilities change
4. Include contact info for user support

Example Configuration (nostr-rs-relay)

[info]
name = "My Relay"
description = "A personal Nostr relay"
pubkey = "your_pubkey_here"
contact = "admin@example.com"

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Tools

nostr.watch

nostr.watch uses NIP-11 to display:

• Relay health and uptime
• Supported NIPs
• Geographic location
• Payment requirements

Relay Testing

Many clients show relay info in settings:

• Connection status
• Supported features
• Limitations
• Operator info

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Common Questions

What if a relay doesn’t support NIP-11?

Clients should handle missing info gracefully. Assume basic NIP-01 support and handle errors for unsupported features.

How often should I check relay info?

Cache the info and check periodically (hourly is reasonable). Relay capabilities rarely change.

Can relay info be verified?

The pubkey field allows signing announcements, but currently the info document itself isn’t signed. Trust depends on HTTPS and relay reputation.

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Summary

NIP-11 enables relay discovery and feature detection:

• Clients understand what relays offer
• Operators advertise their capabilities
• Users make informed relay choices
• Ecosystem becomes more interoperable

Every relay should implement NIP-11 for a better Nostr experience.

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Last updated: January 2026 Official specification: GitHub