diff --git a/package.yaml b/package.yaml
index 610266e82..26936b4af 100644
--- a/package.yaml
+++ b/package.yaml
@@ -47,6 +47,7 @@ dependencies:
   - direct-sqlcipher == 2.3.*
   - directory == 1.3.*
   - filepath == 1.4.*
+  - hashable == 1.4.*
   - hourglass == 0.2.*
   - http-types == 0.12.*
   - http2 >= 4.2.2 && < 4.3
diff --git a/simplexmq.cabal b/simplexmq.cabal
index 5426aa4ca..90b507f3c 100644
--- a/simplexmq.cabal
+++ b/simplexmq.cabal
@@ -236,6 +236,7 @@ library
     , direct-sqlcipher ==2.3.*
     , directory ==1.3.*
     , filepath ==1.4.*
+    , hashable ==1.4.*
     , hourglass ==0.2.*
     , http-types ==0.12.*
     , http2 >=4.2.2 && <4.3
@@ -310,6 +311,7 @@ executable ntf-server
     , direct-sqlcipher ==2.3.*
     , directory ==1.3.*
     , filepath ==1.4.*
+    , hashable ==1.4.*
     , hourglass ==0.2.*
     , http-types ==0.12.*
     , http2 >=4.2.2 && <4.3
@@ -389,6 +391,7 @@ executable smp-server
     , directory ==1.3.*
     , file-embed
     , filepath ==1.4.*
+    , hashable ==1.4.*
     , hourglass ==0.2.*
     , http-types ==0.12.*
     , http2 >=4.2.2 && <4.3
@@ -467,6 +470,7 @@ executable xftp
     , direct-sqlcipher ==2.3.*
     , directory ==1.3.*
     , filepath ==1.4.*
+    , hashable ==1.4.*
     , hourglass ==0.2.*
     , http-types ==0.12.*
     , http2 >=4.2.2 && <4.3
@@ -542,6 +546,7 @@ executable xftp-server
     , direct-sqlcipher ==2.3.*
     , directory ==1.3.*
     , filepath ==1.4.*
+    , hashable ==1.4.*
     , hourglass ==0.2.*
     , http-types ==0.12.*
     , http2 >=4.2.2 && <4.3
@@ -653,6 +658,7 @@ test-suite simplexmq-test
     , directory ==1.3.*
     , filepath ==1.4.*
     , generic-random ==1.5.*
+    , hashable ==1.4.*
     , hourglass ==0.2.*
     , hspec ==2.11.*
     , hspec-core ==2.11.*
diff --git a/src/Simplex/FileTransfer/Server/Stats.hs b/src/Simplex/FileTransfer/Server/Stats.hs
index 8737e6f78..a7951a65a 100644
--- a/src/Simplex/FileTransfer/Server/Stats.hs
+++ b/src/Simplex/FileTransfer/Server/Stats.hs
@@ -11,7 +11,6 @@ import Data.IORef
 import Data.Int (Int64)
 import Data.Time.Clock (UTCTime)
 import Simplex.Messaging.Encoding.String
-import Simplex.Messaging.Protocol (SenderId)
 import Simplex.Messaging.Server.Stats (PeriodStats, PeriodStatsData, getPeriodStatsData, newPeriodStats, setPeriodStats)
 
 data FileServerStats = FileServerStats
@@ -21,7 +20,7 @@ data FileServerStats = FileServerStats
     filesUploaded :: IORef Int,
     filesExpired :: IORef Int,
     filesDeleted :: IORef Int,
-    filesDownloaded :: PeriodStats SenderId,
+    filesDownloaded :: PeriodStats,
     fileDownloads :: IORef Int,
     fileDownloadAcks :: IORef Int,
     filesCount :: IORef Int,
@@ -35,7 +34,7 @@ data FileServerStatsData = FileServerStatsData
     _filesUploaded :: Int,
     _filesExpired :: Int,
     _filesDeleted :: Int,
-    _filesDownloaded :: PeriodStatsData SenderId,
+    _filesDownloaded :: PeriodStatsData,
     _fileDownloads :: Int,
     _fileDownloadAcks :: Int,
     _filesCount :: Int,
diff --git a/src/Simplex/Messaging/Encoding/String.hs b/src/Simplex/Messaging/Encoding/String.hs
index 8995b9679..97e7d087b 100644
--- a/src/Simplex/Messaging/Encoding/String.hs
+++ b/src/Simplex/Messaging/Encoding/String.hs
@@ -28,6 +28,8 @@ import Data.ByteString.Char8 (ByteString)
 import qualified Data.ByteString.Char8 as B
 import Data.Char (isAlphaNum)
 import Data.Int (Int64)
+import Data.IntSet (IntSet)
+import qualified Data.IntSet as IS
 import qualified Data.List.NonEmpty as L
 import Data.Set (Set)
 import qualified Data.Set as S
@@ -39,7 +41,7 @@ import Data.Time.Format.ISO8601
 import Data.Word (Word16, Word32)
 import Simplex.Messaging.Encoding
 import Simplex.Messaging.Parsers (parseAll)
-import Simplex.Messaging.Util ((<$?>))
+import Simplex.Messaging.Util (bshow, (<$?>))
 
 class TextEncoding a where
   textEncode :: a -> Text
@@ -125,15 +127,15 @@ instance StrEncoding Bool where
   {-# INLINE strP #-}
 
 instance StrEncoding Int where
-  strEncode = B.pack . show
+  strEncode = bshow
   {-# INLINE strEncode #-}
-  strP = A.decimal
+  strP = A.signed A.decimal
   {-# INLINE strP #-}
 
 instance StrEncoding Int64 where
-  strEncode = B.pack . show
+  strEncode = bshow
   {-# INLINE strEncode #-}
-  strP = A.decimal
+  strP = A.signed A.decimal
   {-# INLINE strP #-}
 
 instance StrEncoding SystemTime where
@@ -160,6 +162,10 @@ instance (StrEncoding a, Ord a) => StrEncoding (Set a) where
   strEncode = strEncodeList . S.toList
   strP = S.fromList <$> listItem `A.sepBy'` A.char ','
 
+instance StrEncoding IntSet where
+  strEncode = strEncodeList . IS.toList
+  strP = IS.fromList <$> listItem `A.sepBy'` A.char ','
+
 listItem :: StrEncoding a => Parser a
 listItem = parseAll strP <$?> A.takeTill (\c -> c == ',' || c == ' ' || c == '\n')
 
diff --git a/src/Simplex/Messaging/Notifications/Server/Stats.hs b/src/Simplex/Messaging/Notifications/Server/Stats.hs
index 2c469e335..d05257664 100644
--- a/src/Simplex/Messaging/Notifications/Server/Stats.hs
+++ b/src/Simplex/Messaging/Notifications/Server/Stats.hs
@@ -10,8 +10,6 @@ import qualified Data.ByteString.Char8 as B
 import Data.IORef
 import Data.Time.Clock (UTCTime)
 import Simplex.Messaging.Encoding.String
-import Simplex.Messaging.Notifications.Protocol (NtfTokenId)
-import Simplex.Messaging.Protocol (NotifierId)
 import Simplex.Messaging.Server.Stats
 
 data NtfServerStats = NtfServerStats
@@ -23,8 +21,8 @@ data NtfServerStats = NtfServerStats
     subDeleted :: IORef Int,
     ntfReceived :: IORef Int,
     ntfDelivered :: IORef Int,
-    activeTokens :: PeriodStats NtfTokenId,
-    activeSubs :: PeriodStats NotifierId
+    activeTokens :: PeriodStats,
+    activeSubs :: PeriodStats
   }
 
 data NtfServerStatsData = NtfServerStatsData
@@ -36,8 +34,8 @@ data NtfServerStatsData = NtfServerStatsData
     _subDeleted :: Int,
     _ntfReceived :: Int,
     _ntfDelivered :: Int,
-    _activeTokens :: PeriodStatsData NtfTokenId,
-    _activeSubs :: PeriodStatsData NotifierId
+    _activeTokens :: PeriodStatsData,
+    _activeSubs :: PeriodStatsData
   }
 
 newNtfServerStats :: UTCTime -> IO NtfServerStats
diff --git a/src/Simplex/Messaging/Server.hs b/src/Simplex/Messaging/Server.hs
index e84f26a5a..d5ba6695f 100644
--- a/src/Simplex/Messaging/Server.hs
+++ b/src/Simplex/Messaging/Server.hs
@@ -62,7 +62,6 @@ import Data.List.NonEmpty (NonEmpty (..), (<|))
 import qualified Data.List.NonEmpty as L
 import qualified Data.Map.Strict as M
 import Data.Maybe (catMaybes, fromMaybe, isJust, isNothing)
-import qualified Data.Set as S
 import qualified Data.Text as T
 import Data.Text.Encoding (decodeLatin1)
 import Data.Time.Clock (UTCTime (..), diffTimeToPicoseconds, getCurrentTime)
@@ -472,7 +471,7 @@ smpServer started cfg@ServerConfig {transports, transportConfig = tCfg} = do
                 putStat "qDeletedAllB" qDeletedAllB
                 putStat "qDeletedNew" qDeletedNew
                 putStat "qDeletedSecured" qDeletedSecured
-                getStat (day . activeQueues) >>= \v -> hPutStrLn h $ "daily active queues: " <> show (S.size v)
+                getStat (day . activeQueues) >>= \v -> hPutStrLn h $ "daily active queues: " <> show (IS.size v)
                 -- removed to reduce memory usage
                 -- getStat (day . subscribedQueues) >>= \v -> hPutStrLn h $ "daily subscribed queues: " <> show (S.size v)
                 putStat "qSub" qSub
diff --git a/src/Simplex/Messaging/Server/Stats.hs b/src/Simplex/Messaging/Server/Stats.hs
index 60f55100e..097ddb607 100644
--- a/src/Simplex/Messaging/Server/Stats.hs
+++ b/src/Simplex/Messaging/Server/Stats.hs
@@ -10,8 +10,12 @@ module Simplex.Messaging.Server.Stats where
 
 import Control.Applicative (optional, (<|>))
 import qualified Data.Attoparsec.ByteString.Char8 as A
+import Data.ByteString.Char8 (ByteString)
 import qualified Data.ByteString.Char8 as B
+import Data.Hashable (hash)
 import Data.IORef
+import Data.IntSet (IntSet)
+import qualified Data.IntSet as IS
 import Data.Set (Set)
 import qualified Data.Set as S
 import Data.Time.Calendar.Month (pattern MonthDay)
@@ -19,7 +23,7 @@ import Data.Time.Calendar.OrdinalDate (mondayStartWeek)
 import Data.Time.Clock (UTCTime (..))
 import GHC.IORef (atomicSwapIORef)
 import Simplex.Messaging.Encoding.String
-import Simplex.Messaging.Protocol (RecipientId)
+import Simplex.Messaging.Protocol (EntityId (..))
 import Simplex.Messaging.Util (atomicModifyIORef'_, unlessM)
 
 data ServerStats = ServerStats
@@ -57,11 +61,11 @@ data ServerStats = ServerStats
     msgGetDuplicate :: IORef Int,
     msgGetProhibited :: IORef Int,
     msgExpired :: IORef Int,
-    activeQueues :: PeriodStats RecipientId,
-    -- subscribedQueues :: PeriodStats RecipientId, -- this stat uses too much memory
+    activeQueues :: PeriodStats,
+    -- subscribedQueues :: PeriodStats, -- this stat uses too much memory
     msgSentNtf :: IORef Int, -- sent messages with NTF flag
     msgRecvNtf :: IORef Int, -- received messages with NTF flag
-    activeQueuesNtf :: PeriodStats RecipientId,
+    activeQueuesNtf :: PeriodStats,
     msgNtfs :: IORef Int, -- messages notications delivered to NTF server (<= msgSentNtf)
     msgNtfNoSub :: IORef Int, -- no subscriber to notifications (e.g., NTF server not connected)
     msgNtfLost :: IORef Int, -- notification is lost because NTF delivery queue is full
@@ -108,10 +112,10 @@ data ServerStatsData = ServerStatsData
     _msgGetDuplicate :: Int,
     _msgGetProhibited :: Int,
     _msgExpired :: Int,
-    _activeQueues :: PeriodStatsData RecipientId,
+    _activeQueues :: PeriodStatsData,
     _msgSentNtf :: Int,
     _msgRecvNtf :: Int,
-    _activeQueuesNtf :: PeriodStatsData RecipientId,
+    _activeQueuesNtf :: PeriodStatsData,
     _msgNtfs :: Int,
     _msgNtfNoSub :: Int,
     _msgNtfLost :: Int,
@@ -483,7 +487,7 @@ instance StrEncoding ServerStatsData where
           pure PeriodStatsData {_day, _week, _month}
     _subscribedQueues <-
       optional ("subscribedQueues:" <* A.endOfLine) >>= \case
-        Just _ -> newPeriodStatsData <$ (strP @(PeriodStatsData RecipientId) <* optional A.endOfLine)
+        Just _ -> newPeriodStatsData <$ (strP @PeriodStatsData <* optional A.endOfLine)
         _ -> pure newPeriodStatsData
     _activeQueuesNtf <-
       optional ("activeQueuesNtf:" <* A.endOfLine) >>= \case
@@ -552,30 +556,30 @@ instance StrEncoding ServerStatsData where
           Just _ -> strP <* optional A.endOfLine
           _ -> pure newProxyStatsData
 
-data PeriodStats a = PeriodStats
-  { day :: IORef (Set a),
-    week :: IORef (Set a),
-    month :: IORef (Set a)
+data PeriodStats = PeriodStats
+  { day :: IORef IntSet,
+    week :: IORef IntSet,
+    month :: IORef IntSet
   }
 
-newPeriodStats :: IO (PeriodStats a)
+newPeriodStats :: IO PeriodStats
 newPeriodStats = do
-  day <- newIORef S.empty
-  week <- newIORef S.empty
-  month <- newIORef S.empty
+  day <- newIORef IS.empty
+  week <- newIORef IS.empty
+  month <- newIORef IS.empty
   pure PeriodStats {day, week, month}
 
-data PeriodStatsData a = PeriodStatsData
-  { _day :: Set a,
-    _week :: Set a,
-    _month :: Set a
+data PeriodStatsData = PeriodStatsData
+  { _day :: IntSet,
+    _week :: IntSet,
+    _month :: IntSet
   }
   deriving (Show)
 
-newPeriodStatsData :: PeriodStatsData a
-newPeriodStatsData = PeriodStatsData {_day = S.empty, _week = S.empty, _month = S.empty}
+newPeriodStatsData :: PeriodStatsData
+newPeriodStatsData = PeriodStatsData {_day = IS.empty, _week = IS.empty, _month = IS.empty}
 
-getPeriodStatsData :: PeriodStats a -> IO (PeriodStatsData a)
+getPeriodStatsData :: PeriodStats -> IO PeriodStatsData
 getPeriodStatsData s = do
   _day <- readIORef $ day s
   _week <- readIORef $ week s
@@ -583,20 +587,22 @@ getPeriodStatsData s = do
   pure PeriodStatsData {_day, _week, _month}
 
 -- this function is not thread safe, it is used on server start only
-setPeriodStats :: PeriodStats a -> PeriodStatsData a -> IO ()
+setPeriodStats :: PeriodStats -> PeriodStatsData -> IO ()
 setPeriodStats s d = do
   writeIORef (day s) $! _day d
   writeIORef (week s) $! _week d
   writeIORef (month s) $! _month d
 
-instance (Ord a, StrEncoding a) => StrEncoding (PeriodStatsData a) where
+instance StrEncoding PeriodStatsData where
   strEncode PeriodStatsData {_day, _week, _month} =
-    "day=" <> strEncode _day <> "\nweek=" <> strEncode _week <> "\nmonth=" <> strEncode _month
+    "dayHashes=" <> strEncode _day <> "\nweekHashes=" <> strEncode _week <> "\nmonthHashes=" <> strEncode _month
   strP = do
-    _day <- "day=" *> strP <* A.endOfLine
-    _week <- "week=" *> strP <* A.endOfLine
-    _month <- "month=" *> strP
+    _day <- ("day=" *> bsSetP <|> "dayHashes=" *> strP) <* A.endOfLine
+    _week <- ("week=" *> bsSetP <|> "weekHashes=" *> strP) <* A.endOfLine
+    _month <- "month=" *> bsSetP <|> "monthHashes=" *> strP
     pure PeriodStatsData {_day, _week, _month}
+    where
+      bsSetP = S.foldl' (\s -> (`IS.insert` s) . hash) IS.empty <$> strP @(Set ByteString)
 
 data PeriodStatCounts = PeriodStatCounts
   { dayCount :: String,
@@ -604,7 +610,7 @@ data PeriodStatCounts = PeriodStatCounts
     monthCount :: String
   }
 
-periodStatCounts :: forall a. PeriodStats a -> UTCTime -> IO PeriodStatCounts
+periodStatCounts :: PeriodStats -> UTCTime -> IO PeriodStatCounts
 periodStatCounts ps ts = do
   let d = utctDay ts
       (_, wDay) = mondayStartWeek d
@@ -614,17 +620,18 @@ periodStatCounts ps ts = do
   monthCount <- periodCount mDay $ month ps
   pure PeriodStatCounts {dayCount, weekCount, monthCount}
   where
-    periodCount :: Int -> IORef (Set a) -> IO String
-    periodCount 1 ref = show . S.size <$> atomicSwapIORef ref S.empty
+    periodCount :: Int -> IORef IntSet -> IO String
+    periodCount 1 ref = show . IS.size <$> atomicSwapIORef ref IS.empty
     periodCount _ _ = pure ""
 
-updatePeriodStats :: Ord a => PeriodStats a -> a -> IO ()
-updatePeriodStats ps pId = do
+updatePeriodStats :: PeriodStats -> EntityId -> IO ()
+updatePeriodStats ps (EntityId pId) = do
   updatePeriod $ day ps
   updatePeriod $ week ps
   updatePeriod $ month ps
   where
-    updatePeriod ref = unlessM (S.member pId <$> readIORef ref) $ atomicModifyIORef'_ ref $ S.insert pId
+    ph = hash pId
+    updatePeriod ref = unlessM (IS.member ph <$> readIORef ref) $ atomicModifyIORef'_ ref $ IS.insert ph
 
 data ProxyStats = ProxyStats
   { pRequests :: IORef Int,
diff --git a/tests/ServerTests.hs b/tests/ServerTests.hs
index d3154e228..63508a033 100644
--- a/tests/ServerTests.hs
+++ b/tests/ServerTests.hs
@@ -25,7 +25,8 @@ import Data.Bifunctor (first)
 import Data.ByteString.Base64
 import Data.ByteString.Char8 (ByteString)
 import qualified Data.ByteString.Char8 as B
-import qualified Data.Set as S
+import Data.Hashable (hash)
+import qualified Data.IntSet as IS
 import Data.Type.Equality
 import GHC.Stack (withFrozenCallStack)
 import SMPClient
@@ -675,9 +676,9 @@ checkStats s qs sent received = do
   _msgSentNtf s `shouldBe` 0
   _msgRecvNtf s `shouldBe` 0
   let PeriodStatsData {_day, _week, _month} = _activeQueues s
-  S.toList _day `shouldBe` qs
-  S.toList _week `shouldBe` qs
-  S.toList _month `shouldBe` qs
+  IS.toList _day `shouldBe` map (hash . unEntityId) qs
+  IS.toList _week `shouldBe` map (hash . unEntityId) qs
+  IS.toList _month `shouldBe` map (hash . unEntityId) qs
 
 testRestoreExpireMessages :: ATransport -> Spec
 testRestoreExpireMessages at@(ATransport t) =