NIP-05 Identity Setup

Overview

Set up NIP-05 DNS-based identity verification so Nostr clients can map human-readable identifiers (like bob@example.com) to hex public keys. This skill covers creating the /.well-known/nostr.json endpoint, configuring CORS headers, updating kind:0 profiles, and debugging verification failures.

When to Use

• Setting up NIP-05 verification for a domain
• Creating or editing a /.well-known/nostr.json file
• Configuring web server CORS headers for Nostr clients
• Updating a kind:0 profile with a nip05 field
• Debugging why NIP-05 verification is failing
• Setting up the _@domain root identifier

Do NOT use when:

• Building a Nostr relay (that's relay protocol)
• Working with NIP-19 bech32 encoding (npub/nsec display format)
• Implementing Nostr event signing or key management

Workflow

1. Determine the Setup Type

Ask: "Static file or dynamic server?"

2. Create the nostr.json File

The file maps human-readable names to hex public keys.

Format:

{
  "names": {
    "bob": "b0635d6a9851d3aed0cd6c495b282167acf761729078d975fc341b22650b07b9"
  },
  "relays": {
    "b0635d6a9851d3aed0cd6c495b282167acf761729078d975fc341b22650b07b9": [
      "wss://relay.example.com",
      "wss://relay2.example.com"
    ]
  }
}

Critical rules:

• Public keys MUST be 64-character lowercase hex (NOT npub bech32 format)
• The names object is REQUIRED
• The relays object is RECOMMENDED — it helps clients discover where to find the user
• Local-part (the name) MUST only contain a-z0-9-_. (lowercase, no uppercase)
• _ is the special "root" identifier — _@example.com displays as just example.com in clients

Root identifier example:

{
  "names": {
    "_": "b0635d6a9851d3aed0cd6c495b282167acf761729078d975fc341b22650b07b9"
  }
}

This lets the user be identified as just example.com instead of bob@example.com.

3. Serve the File Correctly

The file MUST be served at exactly:

https://<domain>/.well-known/nostr.json?name=<local-part>

Three non-negotiable requirements:

1. HTTPS only — HTTP will not work. Clients only fetch over HTTPS.
2. CORS header — Response MUST include Access-Control-Allow-Origin: * because JavaScript Nostr clients run in browsers and are blocked by CORS policies without this header.
3. No redirects — The endpoint MUST NOT return HTTP redirects (301, 302, etc.). Fetchers MUST ignore redirects per the NIP-05 spec. This is a security constraint.

The ?name=<local-part> query string format exists so both static files and dynamic servers work. A static file ignores the query string and returns all names; a dynamic server can filter by name.

See references/server-configs.md for Nginx, Apache, Caddy, and Node.js configuration examples.

4. Update the Kind:0 Profile

The user's kind:0 metadata event must include the nip05 field:

{
  "kind": 0,
  "content": "{\"name\":\"bob\",\"nip05\":\"bob@example.com\",\"about\":\"A Nostr user\",\"picture\":\"https://example.com/avatar.jpg\"}"
}

The nip05 value format is <local-part>@<domain> — it looks like an email address but is NOT an email address.

Verification flow (what clients do):

1. Client sees "nip05": "bob@example.com" in a kind:0 event
2. Client splits into local-part bob and domain example.com
3. Client fetches https://example.com/.well-known/nostr.json?name=bob
4. Client checks if response.names.bob matches the event's pubkey
5. If match → identity is verified and displayed

5. Test the Setup

Verify the endpoint returns correct JSON:

curl -s https://example.com/.well-known/nostr.json?name=bob | jq .

Verify CORS headers are present:

curl -sI https://example.com/.well-known/nostr.json?name=bob | grep -i ^access-control
# Expected: Access-Control-Allow-Origin: *

Verify no redirects:

curl -sI -o /dev/null -w "%{http_code}" https://example.com/.well-known/nostr.json?name=bob
# Expected: 200 (NOT 301, 302, 307, 308)

Verify the pubkey is hex (not npub):

curl -s https://example.com/.well-known/nostr.json?name=bob | jq -r '.names.bob' | grep -E '^[0-9a-f]{64}$'
# Should match — 64 lowercase hex characters

Checklist

• nostr.json file created with correct names mapping
• Public keys are 64-char lowercase hex (not npub)
• Local-parts use only a-z0-9-_. characters
• File served over HTTPS
• Access-Control-Allow-Origin: * header present
• No HTTP redirects on the endpoint
• relays object included (recommended)
• Kind:0 profile updated with nip05 field
• Endpoint tested with curl and returns 200 with correct JSON

Common Mistakes

Quick Reference

Key Principles

1. Hex keys, never npub — The nostr.json file uses raw 64-character lowercase hex public keys. npub is a display format (NIP-19) and must never appear in nostr.json. This is the single most common mistake.

2. CORS is mandatory — Without Access-Control-Allow-Origin: *, every browser-based Nostr client silently fails to verify the identity. The user sees no error — verification just doesn't work.

3. No redirects, ever — HTTP redirects are a security risk in this context. The spec explicitly requires fetchers to ignore them. Common culprits: trailing-slash redirects, HTTP→HTTPS redirects on the endpoint itself, and www→non-www redirects.

4. Identification, not verification — NIP-05 identifies users (maps human-readable names to keys), it does not verify trust. The exception is well-known domains (companies, projects) where domain ownership itself implies trust.

5. Clients follow pubkeys, not NIP-05 addresses — If a user follows bob@example.com, the client stores the pubkey, not the address. If the NIP-05 mapping changes later, the client unfollows the address display but keeps following the pubkey.