diff --git a/auth/authenticate.py b/auth/authenticate.py
index 95695604..242d2793 100644
--- a/auth/authenticate.py
+++ b/auth/authenticate.py
@@ -9,7 +9,7 @@ from auth.credentials import AuthCredentials, AuthUser
 from services.auth.users import UserStorage
 from settings import SESSION_TOKEN_HEADER
 from auth.tokenstorage import SessionToken
-from base.exceptions import InvalidToken
+from base.exceptions import InvalidToken, OperationNotAllowed, Unauthorized
 
 
 class JWTAuthenticate(AuthenticationBackend):
@@ -30,27 +30,26 @@ class JWTAuthenticate(AuthenticationBackend):
         try:
             if len(token.split('.')) > 1:
                 payload = await SessionToken.verify(token)
+                if payload is None:
+                    return AuthCredentials(scopes=[]), AuthUser(user_id=None)
+                user = await UserStorage.get_user(payload.user_id)
+                if not user:
+                    return AuthCredentials(scopes=[]), AuthUser(user_id=None)
+                scopes = await user.get_permission()
+                return (
+                    AuthCredentials(
+                        user_id=payload.user_id,
+                        scopes=scopes,
+                        logged_in=True
+                    ),
+                    user,
+                )
             else:
                 InvalidToken("please try again")
         except Exception as exc:
             print("[auth.authenticate] session token verify error")
             print(exc)
-            return AuthCredentials(scopes=[], error_message=str(exc)), AuthUser(
-                user_id=None
-            )
-
-        if payload is None:
-            return AuthCredentials(scopes=[]), AuthUser(user_id=None)
-
-        user = await UserStorage.get_user(payload.user_id)
-        if not user:
-            return AuthCredentials(scopes=[]), AuthUser(user_id=None)
-
-        scopes = await user.get_permission()
-        return (
-            AuthCredentials(user_id=payload.user_id, scopes=scopes, logged_in=True),
-            user,
-        )
+            return AuthCredentials(scopes=[], error_message=str(exc)), AuthUser(user_id=None)
 
 
 def login_required(func):
@@ -58,10 +57,9 @@ def login_required(func):
     async def wrap(parent, info: GraphQLResolveInfo, *args, **kwargs):
         # print('[auth.authenticate] login required for %r with info %r' % (func, info))  # debug only
         auth: AuthCredentials = info.context["request"].auth
-        if auth and auth.user_id:
-            print(auth)  # debug only
+        # print(auth)
         if not auth.logged_in:
-            return {"error": auth.error_message or "Please login"}
+            raise OperationNotAllowed(auth.error_message or "Please login")
         return await func(parent, info, *args, **kwargs)
 
     return wrap
@@ -73,9 +71,9 @@ def permission_required(resource, operation, func):
         print('[auth.authenticate] permission_required for %r with info %r' % (func, info))  # debug only
         auth: AuthCredentials = info.context["request"].auth
         if not auth.logged_in:
-            return {"error": auth.error_message or "Please login"}
+            raise Unauthorized(auth.error_message or "Please login")
 
-        # TODO: add check permission logix
+        # TODO: add actual check permission logix here
 
         return await func(parent, info, *args, **kwargs)
 
diff --git a/auth/credentials.py b/auth/credentials.py
index 401ae420..15738d16 100644
--- a/auth/credentials.py
+++ b/auth/credentials.py
@@ -2,7 +2,7 @@ from typing import List, Optional, Text
 
 from pydantic import BaseModel
 
-from base.exceptions import OperationNotAllowed
+from base.exceptions import Unauthorized
 
 
 class Permission(BaseModel):
@@ -17,11 +17,13 @@ class AuthCredentials(BaseModel):
 
     @property
     def is_admin(self):
+        # TODO: check admin logix
         return True
 
     async def permissions(self) -> List[Permission]:
         if self.user_id is None:
-            raise OperationNotAllowed("Please login first")
+            raise Unauthorized("Please login first")
+        # TODO: implement permissions logix
         return NotImplemented()
 
 
diff --git a/auth/jwtcodec.py b/auth/jwtcodec.py
index c2feacd3..387df057 100644
--- a/auth/jwtcodec.py
+++ b/auth/jwtcodec.py
@@ -34,7 +34,7 @@ class JWTCodec:
                 issuer="discours"
             )
             r = TokenPayload(**payload)
-            print('[auth.jwtcodec] debug payload %r' % r)
+            # print('[auth.jwtcodec] debug payload %r' % r)
             return r
         except jwt.InvalidIssuedAtError:
             print('[auth.jwtcodec] invalid issued at: %r' % r)
diff --git a/base/redis.py b/base/redis.py
index 7468af0a..ccc3758a 100644
--- a/base/redis.py
+++ b/base/redis.py
@@ -12,6 +12,7 @@ class RedisCache:
         if self._instance is not None:
             return
         self._instance = await from_url(self._uri, encoding="utf-8")
+        # print(self._instance)
 
     async def disconnect(self):
         if self._instance is None:
@@ -23,10 +24,11 @@ class RedisCache:
     async def execute(self, command, *args, **kwargs):
         while not self._instance:
             await sleep(1)
-            try:
-                await self._instance.execute_command(command, *args, **kwargs)
-            except Exception:
-                pass
+        try:
+            print("[redis] " + command + ' ' + ' '.join(args))
+            return await self._instance.execute_command(command, *args, **kwargs)
+        except Exception:
+            pass
 
     async def lrange(self, key, start, stop):
         return await self._instance.lrange(key, start, stop)
diff --git a/main.py b/main.py
index 3e1deaae..49746195 100644
--- a/main.py
+++ b/main.py
@@ -20,6 +20,7 @@ from services.stat.reacted import ReactedStorage
 from services.stat.topicstat import TopicStat
 from services.stat.viewed import ViewedStorage
 from services.zine.gittask import GitTask
+from services.zine.shoutauthor import ShoutAuthorStorage
 from settings import DEV_SERVER_STATUS_FILE_NAME
 
 import_module("resolvers")
@@ -39,11 +40,14 @@ async def start_up():
     print(views_stat_task)
     reacted_storage_task = asyncio.create_task(ReactedStorage.worker())
     print(reacted_storage_task)
+    shout_author_task = asyncio.create_task(ShoutAuthorStorage.worker())
+    print(shout_author_task)
     topic_stat_task = asyncio.create_task(TopicStat.worker())
     print(topic_stat_task)
     git_task = asyncio.create_task(GitTask.git_task_worker())
     print(git_task)
 
+
 async def dev_start_up():
     if exists(DEV_SERVER_STATUS_FILE_NAME):
         return
diff --git a/migration/tables/users.py b/migration/tables/users.py
index fe9b7374..6db7a243 100644
--- a/migration/tables/users.py
+++ b/migration/tables/users.py
@@ -17,7 +17,7 @@ def migrate(entry):
         "username": email,
         "email": email,
         "createdAt": parse(entry["createdAt"]),
-        "emailConfirmed": bool(entry["emails"][0]["verified"]),
+        "emailConfirmed": ("@discours.io" in email) or bool(entry["emails"][0]["verified"]),
         "muted": False,  # amnesty
         "bio": entry["profile"].get("bio", ""),
         "notifications": [],
diff --git a/resolvers/__init__.py b/resolvers/__init__.py
index fccca3a0..da8800a2 100644
--- a/resolvers/__init__.py
+++ b/resolvers/__init__.py
@@ -48,8 +48,8 @@ from resolvers.zine.load import (
 from resolvers.inbox.chats import (
     create_chat,
     delete_chat,
-    update_chat,
-    invite_to_chat
+    update_chat
+
 )
 from resolvers.inbox.messages import (
     create_message,
@@ -111,7 +111,6 @@ __all__ = [
     # inbox
     "load_chats",
     "load_messages_by",
-    "invite_to_chat",
     "create_chat",
     "delete_chat",
     "update_chat",
diff --git a/resolvers/auth.py b/resolvers/auth.py
index d6f1d40b..317d2733 100644
--- a/resolvers/auth.py
+++ b/resolvers/auth.py
@@ -13,7 +13,7 @@ from auth.identity import Identity, Password
 from auth.jwtcodec import JWTCodec
 from auth.tokenstorage import TokenStorage
 from base.exceptions import (BaseHttpException, InvalidPassword, InvalidToken,
-                             ObjectNotExist, OperationNotAllowed)
+                             ObjectNotExist, OperationNotAllowed, Unauthorized)
 from base.orm import local_session
 from base.resolvers import mutation, query
 from orm import Role, User
@@ -37,7 +37,7 @@ async def get_current_user(_, info):
                 "news": await user_subscriptions(user.slug),
             }
     else:
-        raise OperationNotAllowed("No session token present in request, try to login")
+        raise Unauthorized("No session token present in request, try to login")
 
 
 @mutation.field("confirmEmail")
diff --git a/resolvers/inbox/chats.py b/resolvers/inbox/chats.py
index f4b1ca1e..e24acf0c 100644
--- a/resolvers/inbox/chats.py
+++ b/resolvers/inbox/chats.py
@@ -7,43 +7,6 @@ from base.redis import redis
 from base.resolvers import mutation
 
 
-async def add_user_to_chat(user_slug: str, chat_id: str, chat=None):
-    for member in chat["users"]:
-        chats_ids = await redis.execute("GET", f"chats_by_user/{member}")
-        if chats_ids:
-            chats_ids = list(json.loads(chats_ids))
-        else:
-            chats_ids = []
-        if chat_id not in chats_ids:
-            chats_ids.append(chat_id)
-        await redis.execute("SET", f"chats_by_user/{member}", json.dumps(chats_ids))
-
-
-@mutation.field("inviteChat")
-async def invite_to_chat(_, info, invited: str, chat_id: str):
-    ''' invite user with :slug to chat with :chat_id '''
-    user = info.context["request"].user
-    chat = await redis.execute("GET", f"chats/{chat_id}")
-    if not chat:
-        return {
-            "error": "chat not exist"
-        }
-    chat = dict(json.loads(chat))
-    if not chat['private'] and user.slug not in chat['admins']:
-        return {
-            "error": "only admins can invite to private chat",
-            "chat": chat
-        }
-    else:
-        chat["users"].append(invited)
-        await add_user_to_chat(user.slug, chat_id, chat)
-        await redis.execute("SET", f"chats/{chat_id}", json.dumps(chat))
-        return {
-            "error": None,
-            "chat": chat
-        }
-
-
 @mutation.field("updateChat")
 @login_required
 async def update_chat(_, info, chat_new: dict):
@@ -71,9 +34,8 @@ async def update_chat(_, info, chat_new: dict):
             "admins": chat_new.get("admins", chat["admins"]),
             "users": chat_new.get("users", chat["users"])
         })
-    await add_user_to_chat(user.slug, chat_id, chat)
     await redis.execute("SET", f"chats/{chat.id}", json.dumps(chat))
-    await redis.execute("SET", f"chats/{chat.id}/next_message_id", 0)
+    await redis.execute("COMMIT")
 
     return {
         "error": None,
@@ -97,11 +59,22 @@ async def create_chat(_, info, title="", members=[]):
         "users": members,
         "admins": [user.slug, ]
     }
+    # double creation protection
+    cids = await redis.execute("SMEMBERS", f"chats_by_user/{user.slug}")
+    for cid in cids:
+        c = await redis.execute("GET", F"chats/{cid.decode('utf-8')}")
+        isc = [x for x in c["users"] if x not in chat["users"]]
+        if isc == [] and chat["title"] == c["title"]:
+            return {
+                "error": "chat was created before",
+                "chat": chat
+            }
 
-    await add_user_to_chat(user.slug, chat_id, chat)
+    for m in members:
+        await redis.execute("SADD", f"chats_by_user/{m}", chat_id)
     await redis.execute("SET", f"chats/{chat_id}", json.dumps(chat))
     await redis.execute("SET", f"chats/{chat_id}/next_message_id", str(0))
-
+    await redis.execute("COMMIT")
     return {
         "error": None,
         "chat": chat
@@ -117,6 +90,8 @@ async def delete_chat(_, info, chat_id: str):
         chat = dict(json.loads(chat))
         if user.slug in chat['admins']:
             await redis.execute("DEL", f"chats/{chat_id}")
+            await redis.execute("SREM", "chats_by_user/" + user, chat_id)
+            await redis.execute("COMMIT")
     else:
         return {
             "error": "chat not exist"
diff --git a/resolvers/inbox/load.py b/resolvers/inbox/load.py
index cd38690b..871b0700 100644
--- a/resolvers/inbox/load.py
+++ b/resolvers/inbox/load.py
@@ -5,52 +5,51 @@ from auth.authenticate import login_required
 from base.redis import redis
 from base.orm import local_session
 from base.resolvers import query
+from base.exceptions import ObjectNotExist
 from orm.user import User
 from resolvers.zine.profile import followed_authors
 from .unread import get_unread_counter
 
 
-async def load_messages(chatId: str, limit: int, offset: int):
-    ''' load :limit messages for :chatId with :offset '''
+async def load_messages(chat_id: str, limit: int, offset: int):
+    ''' load :limit messages for :chat_id with :offset '''
     messages = []
     message_ids = await redis.lrange(
-        f"chats/{chatId}/message_ids", 0 - offset - limit, 0 - offset
+        f"chats/{chat_id}/message_ids", offset + limit, offset
     )
     if message_ids:
         message_keys = [
-            f"chats/{chatId}/messages/{mid}" for mid in message_ids
+            f"chats/{chat_id}/messages/{mid}" for mid in message_ids
         ]
         messages = await redis.mget(*message_keys)
         messages = [json.loads(msg) for msg in messages]
-    return {
-        "messages": messages,
-        "error": None
-    }
+    return messages
 
 
 @query.field("loadChats")
 @login_required
-async def load_chats(_, info, limit: int, offset: int):
+async def load_chats(_, info, limit: int = 50, offset: int = 0):
     """ load :limit chats of current user with :offset """
     user = info.context["request"].user
-    if user:
-        chats = await redis.execute("GET", f"chats_by_user/{user.slug}")
-        if chats:
-            chats = list(json.loads(chats))[offset:offset + limit]
-        if not chats:
-            chats = []
-        for c in chats:
-            c['messages'] = await load_messages(c['id'], limit, offset)
-            c['unread'] = await get_unread_counter(c['id'], user.slug)
-        return {
-            "chats": chats,
-            "error": None
-        }
-    else:
-        return {
-            "error": "please login",
-            "chats": []
-        }
+    print('[inbox] load user\'s chats')
+    cids = await redis.execute("SMEMBERS", "chats_by_user/" + user.slug)
+    if cids:
+        cids = list(cids)[offset:offset + limit]
+    if not cids:
+        print('[inbox.load] no chats were found')
+        cids = []
+    chats = []
+    for cid in cids:
+        c = await redis.execute("GET", "chats/" + cid.decode("utf-8"))
+        if c:
+            c = json.loads(c)
+            c['messages'] = await load_messages(cid, 50, 0)
+            c['unread'] = await get_unread_counter(cid, user.slug)
+            chats.append(c)
+    return {
+        "chats": chats,
+        "error": None
+    }
 
 
 @query.field("loadMessagesBy")
@@ -58,28 +57,36 @@ async def load_chats(_, info, limit: int, offset: int):
 async def load_messages_by(_, info, by, limit: int = 50, offset: int = 0):
     ''' load :amolimitunt messages of :chat_id with :offset '''
     user = info.context["request"].user
-    my_chats = await redis.execute("GET", f"chats_by_user/{user.slug}")
-    chat_id = by.get('chat')
-    if chat_id:
-        chat = await redis.execute("GET", f"chats/{chat_id}")
+    cids = await redis.execute("SMEMBERS", "chats_by_user/" + user.slug)
+    by_chat = by.get('chat')
+    messages = []
+    if by_chat:
+        chat = await redis.execute("GET", f"chats/{by_chat}")
         if not chat:
-            return {
-                "error": "chat not exist"
-            }
-        messages = await load_messages(chat_id, limit, offset)
-    user_id = by.get('author')
-    if user_id:
-        chats = await redis.execute("GET", f"chats_by_user/{user_id}")
-        our_chats = list(set(chats) & set(my_chats))
-        for c in our_chats:
-            messages += await load_messages(c, limit, offset)
+            raise ObjectNotExist("Chat not exists")
+        messages = await load_messages(by_chat, limit, offset)
+    by_author = by.get('author')
+    if by_author:
+        if not by_chat:
+            # all author's messages
+            by_author_cids = await redis.execute("SMEMBERS", f"chats_by_user/{by_author}")
+            for c in list(by_author_cids & cids):
+                messages += await load_messages(c, limit, offset)
+        else:
+            # author's messages in chat
+            messages = filter(lambda m: m["author"] == by_author, messages)
     body_like = by.get('body')
     if body_like:
-        for c in my_chats:
-            mmm = await load_messages(c, limit, offset)
-            for m in mmm:
-                if body_like in m["body"]:
-                    messages.append(m)
+        if not by_chat:
+            # search in all messages in all user's chats
+            for c in list(cids):
+                mmm = await load_messages(c, limit, offset)
+                for m in mmm:
+                    if body_like in m["body"]:
+                        messages.append(m)
+        else:
+            # search in chat's messages
+            messages = filter(lambda m: body_like in m["body"], messages)
     days = by.get("days")
     if days:
         messages = filter(
diff --git a/resolvers/inbox/unread.py b/resolvers/inbox/unread.py
index 0075a877..d5d2e553 100644
--- a/resolvers/inbox/unread.py
+++ b/resolvers/inbox/unread.py
@@ -17,6 +17,6 @@ async def get_total_unread_counter(user_slug: str):
     if chats:
         chats = json.loads(chats)
         for chat_id in chats:
-            n = await get_unread_counter(chat_id, user_slug)
+            n = await get_unread_counter(chat_id.decode('utf-8'), user_slug)
             unread += n
     return unread
diff --git a/schema.graphql b/schema.graphql
index e1d30873..e08342ec 100644
--- a/schema.graphql
+++ b/schema.graphql
@@ -151,7 +151,6 @@ type Mutation {
   createChat(title: String, members: [String]!): Result!
   updateChat(chat: ChatInput!): Result!
   deleteChat(chatId: String!): Result!
-  inviteChat(chatId: String!, userslug: String!): Result!
 
   createMessage(chat: String!, body: String!, replyTo: String): Result!
   updateMessage(chatId: String!, id: Int!, body: String!): Result!
@@ -515,13 +514,13 @@ type Message {
 type Chat {
   id: String!
   createdAt: Int!
-  createdBy: User!
+  createdBy: String!
   updatedAt: Int!
   title: String
   description: String
-  users: [User]!
-  admins: [User]
-  messages: [Message]!
+  users: [String]!
+  admins: [String]
+  messages: [Message]
   unread: Int
   private: Boolean
 }
diff --git a/services/stat/topicstat.py b/services/stat/topicstat.py
index c95d0850..3a5689e6 100644
--- a/services/stat/topicstat.py
+++ b/services/stat/topicstat.py
@@ -3,7 +3,7 @@ import time
 from base.orm import local_session
 from orm.shout import Shout, ShoutTopic, ShoutAuthor
 from orm.topic import TopicFollower
-from sqlalchemy.sql.expression import select
+# from sqlalchemy.sql.expression import select
 
 
 class TopicStat:
@@ -20,21 +20,19 @@ class TopicStat:
         start = time.time()
         self = TopicStat
         shout_topics = session.query(ShoutTopic, Shout).join(Shout).all()
-        all_shout_authors = session.query(ShoutAuthor).all()
         print("[stat.topics] %d links for shouts" % len(shout_topics))
         for [shout_topic, shout] in shout_topics:
             tpc = shout_topic.topic
-            # shouts by topics
-            # shout = session.query(Shout).where(Shout.slug == shout_topic.shout).first()
             self.shouts_by_topic[tpc] = self.shouts_by_topic.get(tpc, dict())
             self.shouts_by_topic[tpc][shout.slug] = shout
-
-            # authors by topics
-            shout_authors = filter(lambda asa: asa.shout == shout.slug, all_shout_authors)
-
             self.authors_by_topic[tpc] = self.authors_by_topic.get(tpc, dict())
-            for sa in shout_authors:
-                self.authors_by_topic[tpc][sa.shout] = sa.caption
+            authors = session.query(
+                ShoutAuthor.user, ShoutAuthor.caption
+            ).filter(
+                ShoutAuthor.shout == shout.slug
+            ).all()
+            for a in authors:
+                self.authors_by_topic[tpc][a[0]] = a[1]
 
         self.followers_by_topic = {}
         followings = session.query(TopicFollower).all()
diff --git a/services/zine/shoutauthor.py b/services/zine/shoutauthor.py
new file mode 100644
index 00000000..477ff384
--- /dev/null
+++ b/services/zine/shoutauthor.py
@@ -0,0 +1,46 @@
+import asyncio
+from base.orm import local_session
+from orm.shout import ShoutAuthor, Shout
+
+
+class ShoutAuthorStorage:
+    authors_by_shout = {}
+    lock = asyncio.Lock()
+    period = 30 * 60  # sec
+
+    @staticmethod
+    async def load_captions(session):
+        self = ShoutAuthorStorage
+        sas = session.query(ShoutAuthor).join(Shout).all()
+        for sa in sas:
+            self.authors_by_shout[sa.shout] = self.authors_by_shout.get(sa.shout, [])
+            self.authors_by_shout[sa.shout].append([sa.user, sa.caption])
+        print("[zine.authors] %d shouts indexed by authors" % len(self.authors_by_shout))
+
+    @staticmethod
+    async def get_authors(shout):
+        self = ShoutAuthorStorage
+        async with self.lock:
+            return self.authors_by_shout.get(shout, [])
+
+    @staticmethod
+    async def get_author_caption(shout, author):
+        self = ShoutAuthorStorage
+        async with self.lock:
+            for a in self.authors_by_shout.get(shout, []):
+                if author in a:
+                    return a[1]
+        return {"error": "author caption not found"}
+
+    @staticmethod
+    async def worker():
+        self = ShoutAuthorStorage
+        while True:
+            try:
+                with local_session() as session:
+                    async with self.lock:
+                        await self.load_captions(session)
+                        print("[zine.authors] index by authors was updated")
+            except Exception as err:
+                print("[zine.authors] error indexing by author: %s" % (err))
+            await asyncio.sleep(self.period)