diff --git a/client_manager.py b/client_manager.py
index d0a2c0f..cb99b44 100644
--- a/client_manager.py
+++ b/client_manager.py
@@ -18,6 +18,7 @@ from .crud import (
     mark_events_deleted,
     prune_old_events,
 )
+from .helpers import extract_domain
 from .models import NostrAccount, NostrEvent, NostrEventType, NostrFilter, RelaySpec
 
 
@@ -166,6 +167,17 @@ class NostrClientConnection:
     async def _handle_event(self, e: NostrEvent):
         logger.info(f"nostr event: [{e.kind}, {e.pubkey}, '{e.content}']")
         resp_nip20: List[Any] = ["OK", e.id]
+
+        if e.is_auth_response_event:
+            valid, message = self._validate_auth_event(e)
+            if not valid:
+                resp_nip20 += [valid, message]
+                await self._send_msg(resp_nip20)
+                return None
+            self.authenticated = True
+            return None
+
+
         if not self.authenticated and self.client_config.event_requires_auth(e.kind):
             await self._send_msg(["AUTH", self._current_auth_challenge()])
             resp_nip20 += [False, "Relay requires authentication"]
@@ -180,14 +192,14 @@ class NostrClientConnection:
             return None
 
         try:
-            if e.is_replaceable_event():
+            if e.is_replaceable_event:
                 await delete_events(
                     self.relay_id, NostrFilter(kinds=[e.kind], authors=[e.pubkey])
                 )
             await create_event(self.relay_id, e)
             await self._broadcast_event(e)
 
-            if e.is_delete_event():
+            if e.is_delete_event:
                 await self._handle_delete_event(e)
             resp_nip20 += [True, ""]
         except Exception as ex:
@@ -213,7 +225,7 @@ class NostrClientConnection:
         filter = NostrFilter(authors=[event.pubkey])
         filter.ids = [t[1] for t in event.tags if t[0] == "e"]
         events_to_delete = await get_events(self.relay_id, filter, False)
-        ids = [e.id for e in events_to_delete if not e.is_delete_event()]
+        ids = [e.id for e in events_to_delete if not e.is_delete_event]
         await mark_events_deleted(self.relay_id, NostrFilter(ids=ids))
 
     async def _handle_request(self, subscription_id: str, filter: NostrFilter) -> List:
@@ -255,14 +267,32 @@ class NostrClientConnection:
             and len(self.filters) >= self.client_config.max_client_filters
         )
 
-    async def _validate_write(self, e: NostrEvent) -> Tuple[bool, str]:
+    def _validate_auth_event(self, e: NostrEvent) -> Tuple[bool, str]:
         valid, message = self._validate_event(e)
         if not valid:
             return [valid, message]
 
+        relay_tag = e.tag_values("relay")
+        challenge_tag = e.tag_values("challenge")
+        if len(relay_tag) == 0 or len(challenge_tag) == 0:
+            return False, "NIP42 tags are missing"
+        
+        if self.client_config.domain != extract_domain(relay_tag[0]):
+            return False, "Wrong relay domain"
+
+        if self._auth_challenge != challenge_tag[0]:
+            return False, "Wrong chanlange value"
+
+        return True, ""
+
+    async def _validate_write(self, e: NostrEvent) -> Tuple[bool, str]:
+        valid, message = self._validate_event(e)
+        if not valid:
+            return (valid, message)
+
         valid, message = await self._validate_storage(e.pubkey, e.size_bytes)
         if not valid:
-            return [valid, message]
+            return (valid, message)
 
         return True, ""
 
diff --git a/helpers.py b/helpers.py
index bcf5c02..8e0b15d 100644
--- a/helpers.py
+++ b/helpers.py
@@ -1,3 +1,5 @@
+from urllib.parse import urlparse
+
 from bech32 import bech32_decode, convertbits
 
 
@@ -17,3 +19,6 @@ def normalize_public_key(pubkey: str) -> str:
         raise ValueError("Public Key is not valid hex")
     int(pubkey, 16)
     return pubkey
+
+def extract_domain(url: str) -> str:
+    return urlparse(url).netloc
\ No newline at end of file
diff --git a/views_api.py b/views_api.py
index df53d96..f44ca95 100644
--- a/views_api.py
+++ b/views_api.py
@@ -1,6 +1,5 @@
 from http import HTTPStatus
 from typing import List, Optional
-from urllib.parse import urlparse
 
 from fastapi import Depends, Request, WebSocket
 from fastapi.exceptions import HTTPException
@@ -27,7 +26,7 @@ from .crud import (
     get_relays,
     update_relay,
 )
-from .helpers import normalize_public_key
+from .helpers import extract_domain, normalize_public_key
 from .models import BuyOrder, NostrRelay
 
 client_manager = NostrClientManager()
@@ -57,7 +56,7 @@ async def api_create_relay(
         data.id = urlsafe_short_hash()[:8]
 
     try:
-        data.config.domain = urlparse(str(request.url)).netloc
+        data.config.domain = extract_domain(str(request.url))
         relay = await create_relay(wallet.wallet.user, data)
         return relay