diff --git a/Makefile b/Makefile
index ecf4201345..d451a3b0b0 100644
--- a/Makefile
+++ b/Makefile
@@ -18,7 +18,8 @@ fake-aws fake-aws-s3 fake-aws-sqs aws-ingress fluent-bit kibana backoffice		\
 calling-test demo-smtp elasticsearch-curator elasticsearch-external				\
 elasticsearch-ephemeral minio-external cassandra-external						\
 ingress-nginx-controller nginx-ingress-services reaper restund \
-k8ssandra-test-cluster ldap-scim-bridge wire-server-enterprise
+k8ssandra-test-cluster ldap-scim-bridge wire-server-enterprise \
+integration
 KIND_CLUSTER_NAME     := wire-server
 HELM_PARALLELISM      ?= 1 # 1 for sequential tests; 6 for all-parallel tests
 # (run `psql -h localhost -p 5432 -d backendA -U wire-server -w` for the list of options for PSQL_DB)
diff --git a/charts/integration/templates/configmap.yaml b/charts/integration/templates/configmap.yaml
index 82fc989528..4aee4ce200 100644
--- a/charts/integration/templates/configmap.yaml
+++ b/charts/integration/templates/configmap.yaml
@@ -77,14 +77,16 @@ data:
       apiPort: 5380
       dohPort: 5381
 
-    originDomain: federation-test-helper.{{ .Release.Namespace }}.svc.cluster.local
+    # originDomain: federation-test-helper.{{ .Release.Namespace }}.svc.cluster.local
+    # sven-test.wire.link
+    originDomain: dev.zinfra.io
 
     rabbitmq:
       host: rabbitmq
       port: 5671
       adminHost: rabbitmq
-      adminPort: 15671
-      enableTls: true
+      adminPort: 15672
+      enableTls: false
       insecureSkipVerifyTls: true
       vHost: /
 
@@ -310,3 +312,6 @@ data:
 
     integrationTestHostName: integration-headless.{{ .Release.Namespace }}.svc.cluster.local
     cellsEventQueue: cells_events
+    shardingGroupCount: {{ .Values.config.shardingGroupCount }}
+    maxUserNo: {{ .Values.config.maxUserNo }}
+    maxDeliveryDelay: {{ .Values.config.maxDeliveryDelay }}
diff --git a/charts/integration/templates/integration-integration.yaml b/charts/integration/templates/integration-integration.yaml
index f59475280e..b0ff8c19aa 100644
--- a/charts/integration/templates/integration-integration.yaml
+++ b/charts/integration/templates/integration-integration.yaml
@@ -29,10 +29,6 @@ spec:
       secret:
         secretName: "brig"
 
-    - name: "turn-servers"
-      configMap:
-        name: "turn"
-
     - name: "cannon-config"
       configMap:
         name: "cannon"
@@ -65,22 +61,6 @@ spec:
       configMap:
         name: "background-worker"
 
-    - name: "background-worker-secrets"
-      secret:
-        secretName: "background-worker"
-
-    - name: "stern-config"
-      configMap:
-        name: "backoffice"
-
-    - name: "proxy-config"
-      configMap:
-        name: "proxy"
-
-    - name: "proxy-secrets"
-      secret:
-        secretName: "proxy"
-
     - name: "nginz-config"
       configMap:
         name: "nginz"
@@ -89,28 +69,12 @@ spec:
       secret:
         secretName: "nginz"
 
-    - name: elasticsearch-ca
-      secret:
-        secretName: {{ .Values.config.elasticsearch.tlsCaSecretRef.name }}
-
-    - name: redis-ca
-      secret:
-        secretName: {{ .Values.config.redis.tlsCaSecretRef.name }}
-
-    - name: rabbitmq-ca
-      secret:
-        secretName: {{ .Values.config.rabbitmq.tlsCaSecretRef.name }}
-
     {{- if eq (include "useCassandraTLS" .Values.config) "true" }}
     - name: integration-cassandra
       secret:
         secretName: {{ include "cassandraTlsSecretName" .Values.config }}
     {{- end }}
 
-    - name: wire-server-enterprise-config
-      configMap:
-        name: wire-server-enterprise
-
   restartPolicy: Never
 
   initContainers:
@@ -121,14 +85,10 @@ spec:
       {{- toYaml .Values.podSecurityContext | nindent 6 }}
         {{- end }}
     volumeMounts:
-      - name: elasticsearch-ca
-        mountPath: "/certs/elasticsearch"
       {{- if eq (include "useCassandraTLS" .Values.config) "true" }}
       - name: "integration-cassandra"
         mountPath: "/certs/cassandra"
       {{- end }}
-      - name: rabbitmq-ca
-        mountPath: /certs/rabbitmq-ca
     env:
     - name: INTEGRATION_DYNAMIC_BACKENDS_POOLSIZE
       value: "{{ .Values.config.dynamicBackendsPoolsize }}"
@@ -141,32 +101,19 @@ spec:
     - name: RABBITMQ_USERNAME
       valueFrom:
         secretKeyRef:
-          name: brig
+          name: gundeck
           key: rabbitmqUsername
     - name: RABBITMQ_PASSWORD
       valueFrom:
         secretKeyRef:
-          name: brig
+          name: gundeck
           key: rabbitmqPassword
     command:
       - /bin/sh
       - -c
       - |
         set -euo pipefail
-        # FUTUREWORK: Do all of this in the integration test binary
-        integration-dynamic-backends-db-schemas.sh \
-          --host {{ .Values.config.cassandra.host }} \
-          --port {{ .Values.config.cassandra.port }} \
-          --replication-factor {{ .Values.config.cassandra.replicationFactor }} \
-          {{- if eq (include "useCassandraTLS" .Values.config) "true" }}
-          --tls-ca-certificate-file /certs/cassandra/{{- include "cassandraTlsSecretKey" .Values.config }}
-          {{ end }}
-
-        integration-dynamic-backends-brig-index.sh \
-          --elasticsearch-server https://elastic:changeme@{{ .Values.config.elasticsearch.host }}:9200 \
-          --elasticsearch-ca-cert /certs/elasticsearch/{{ .Values.config.elasticsearch.tlsCaSecretRef.key }}
-        integration-dynamic-backends-ses.sh {{ .Values.config.sesEndpointUrl }}
-        integration-dynamic-backends-s3.sh {{ .Values.config.s3EndpointUrl }}
+
         {{- range $name, $dynamicBackend := .Values.config.dynamicBackends }}
         integration-dynamic-backends-vhosts.sh {{ $.Values.config.rabbitmqPutVHostUrl }} {{ $dynamicBackend.federatorExternalHostPrefix}}.{{ $.Release.Namespace }}.svc.cluster.local
         {{- end }}
@@ -176,11 +123,12 @@ spec:
         cpu: "2"
 
   containers:
-  - name: integration
-    image: "{{ .Values.image.repository }}:{{ .Values.image.tag }}"
-        {{- if eq (include "includeSecurityContext" .) "true" }}
+  {{- range $i := until (int .Values.config.shardingGroupCount) }}
+  - name: "integration-{{ int $i}}"
+    image: "{{ $.Values.image.repository }}:{{ $.Values.image.tag }}"
+        {{- if eq (include "includeSecurityContext" $) "true" }}
     securityContext:
-      {{- toYaml .Values.podSecurityContext | nindent 6 }}
+      {{- toYaml $.Values.podSecurityContext | nindent 6 }}
         {{- end }}
     command:
     - /bin/bash
@@ -188,13 +136,13 @@ spec:
     - |
       set -euo pipefail
 
-      if integration --config /etc/wire/integration/integration.yaml; then
+      if TEST_INCLUDE=testBench integration --config /etc/wire/integration/integration.yaml --sharding-group {{ $i }}; then
         exit_code=$?
       else
         exit_code=$?
       fi
 
-      {{- if .Values.config.uploadXml }}
+      {{- if $.Values.config.uploadXml }}
       # In case a different S3 compliant storage is used to upload test result.
       if ! [[ -z "${UPLOAD_XML_AWS_ACCESS_KEY_ID+x}" ]]; then
         export AWS_ACCESS_KEY_ID="$UPLOAD_XML_AWS_ACCESS_KEY_ID"
@@ -210,7 +158,7 @@ spec:
     resources:
       requests:
         memory: "512Mi"
-        cpu: "2"
+        cpu: "0.5"
     volumeMounts:
 
     - name: integration-config
@@ -228,9 +176,6 @@ spec:
     - name: brig-secrets
       mountPath: /etc/wire/brig/secrets
 
-    - name: turn-servers
-      mountPath: /etc/wire/brig/turn
-
     - name: cannon-config
       mountPath: /etc/wire/cannon/conf
 
@@ -243,58 +188,13 @@ spec:
     - name: spar-config
       mountPath: /etc/wire/spar/conf
 
-    - name: federator-config
-      mountPath: /etc/wire/federator/conf
-
-    - name: federator-secrets
-      mountPath: /etc/wire/federator/secrets
-
-    - name: federator-ca
-      mountPath: /etc/wire/federator/ca
-
-    - name: background-worker-config
-      mountPath: /etc/wire/background-worker/conf
-
-    - name: background-worker-secrets
-      mountPath: /etc/wire/background-worker/secrets
-
-    - name: stern-config
-      mountPath: /etc/wire/stern/conf
-
-    - name: proxy-config
-      mountPath: /etc/wire/proxy/conf
-
-    - name: proxy-secrets
-      mountPath: /etc/wire/proxy/secrets
-
     - name: nginz-config
       mountPath: /etc/wire/nginz/conf
 
     - name: nginz-secrets
       mountPath: /etc/wire/nginz/secrets
 
-    - name: elasticsearch-ca
-      mountPath: /etc/wire/brig/elasticsearch-ca
-
-    - name: redis-ca
-      mountPath: /etc/wire/gundeck/redis-ca
-
-    - name: rabbitmq-ca
-      mountPath: /etc/wire/brig/rabbitmq-ca
-
-    - name: rabbitmq-ca
-      mountPath: /etc/wire/galley/rabbitmq-ca
-
-    - name: rabbitmq-ca
-      mountPath: /etc/wire/background-worker/rabbitmq-ca
-
-    - name: rabbitmq-ca
-      mountPath: /etc/wire/gundeck/rabbitmq-ca
-
-    - name: rabbitmq-ca
-      mountPath: /etc/wire/cannon/rabbitmq-ca
-
-    {{- if eq (include "useCassandraTLS" .Values.config) "true" }}
+    {{- if eq (include "useCassandraTLS" $.Values.config) "true" }}
     - name: "integration-cassandra"
       mountPath: "/certs"
 
@@ -311,9 +211,6 @@ spec:
       mountPath: "/etc/wire/spar/cassandra"
     {{- end }}
 
-    - name: wire-server-enterprise-config
-      mountPath: /etc/wire/wire-server-enterprise/conf
-
     env:
     # these dummy values are necessary for Amazonka's "Discover"
     - name: AWS_ACCESS_KEY_ID
@@ -325,35 +222,21 @@ spec:
     - name: RABBITMQ_USERNAME
       valueFrom:
         secretKeyRef:
-          name: brig
+          name: gundeck
           key: rabbitmqUsername
     - name: RABBITMQ_PASSWORD
       valueFrom:
         secretKeyRef:
-          name: brig
+          name: gundeck
           key: rabbitmqPassword
-    - name: RABBITMQ_USERNAME_V0
-      value: "wire-server"
-    - name: RABBITMQ_PASSWORD_V0
-      valueFrom:
-        secretKeyRef:
-          name: rabbitmq-v0
-          key: rabbitmq-password
-    - name: RABBITMQ_USERNAME_V1
-      value: "wire-server"
-    - name: RABBITMQ_PASSWORD_V1
-      valueFrom:
-        secretKeyRef:
-          name: rabbitmq-v1
-          key: rabbitmq-password
-    {{- if hasKey .Values.secrets "redisUsername" }}
+    {{- if hasKey $.Values.secrets "redisUsername" }}
     - name: REDIS_USERNAME
       valueFrom:
         secretKeyRef:
           name: integration
           key: redisUsername
     {{- end }}
-    {{- if hasKey .Values.secrets "redisPassword" }}
+    {{- if hasKey $.Values.secrets "redisPassword" }}
     - name: REDIS_PASSWORD
       valueFrom:
         secretKeyRef:
@@ -362,10 +245,10 @@ spec:
     {{- end }}
     - name: TEST_XML
       value: /tmp/result.xml
-    {{- if .Values.config.uploadXml }}
+    {{- if $.Values.config.uploadXml }}
     - name: UPLOAD_XML_S3_BASE_URL
-      value: {{ .Values.config.uploadXml.baseUrl }}
-    {{- if .Values.secrets.uploadXmlAwsAccessKeyId }}
+      value: {{ $.Values.config.uploadXml.baseUrl }}
+    {{- if $.Values.secrets.uploadXmlAwsAccessKeyId }}
     - name: UPLOAD_XML_AWS_ACCESS_KEY_ID
       valueFrom:
         secretKeyRef:
@@ -379,8 +262,9 @@ spec:
     {{- end }}
     {{- end }}
     - name: ENABLE_FEDERATION_V0
-      value: "1"
+      value: "0"
     - name: ENABLE_FEDERATION_V1
-      value: "1"
+      value: "0"
     - name: ENABLE_FEDERATION_V2
-      value: "1"
+      value: "0"
+  {{- end }}
diff --git a/charts/integration/values.yaml b/charts/integration/values.yaml
index 36305b2be7..5bd5556def 100644
--- a/charts/integration/values.yaml
+++ b/charts/integration/values.yaml
@@ -12,7 +12,7 @@ podSecurityContext:
     type: RuntimeDefault
 
 config:
-  dynamicBackendsPoolsize: 3
+  dynamicBackendsPoolsize: 0
   dynamicBackends:
     dynamic-backend-1:
       federatorExternalHostPrefix: dynamic-backend-1
@@ -118,8 +118,11 @@ config:
   sqsEndpointUrl: http://fake-aws-sqs:4568
   sesEndpointUrl: http://fake-aws-ses:4569
   s3EndpointUrl: http://fake-aws-s3:9000
-  rabbitmqPutVHostUrl: http://rabbitmq:15672/api/vhosts
-
+  rabbitmqPutVHostUrl: http://rabbitmq-b.databases.svc.cluster.local:15672/api/vhosts
+  shardingGroupCount: 3
+  # shardingGroup: 0
+  maxUserNo: 1000
+  maxDeliveryDelay: 120
 tls:
   verify_depth: 1
   # Namespace from which to obtain the secret containing the CA trusted by
diff --git a/integration/default.nix b/integration/default.nix
index 04163fc507..03512c4bc5 100644
--- a/integration/default.nix
+++ b/integration/default.nix
@@ -74,6 +74,7 @@
 , split
 , stm
 , streaming-commons
+, streamly
 , string-conversions
 , system-linux-proc
 , tagged
@@ -179,6 +180,7 @@ mkDerivation {
     split
     stm
     streaming-commons
+    streamly
     string-conversions
     system-linux-proc
     tagged
diff --git a/integration/integration.cabal b/integration/integration.cabal
index 0cdf6972ef..70386331cf 100644
--- a/integration/integration.cabal
+++ b/integration/integration.cabal
@@ -184,6 +184,7 @@ library
     Test.MLS.Unreachable
     Test.NginxZAuthModule
     Test.Notifications
+    Test.NotificationsBenchmark
     Test.OAuth
     Test.PasswordReset
     Test.Presence
@@ -299,6 +300,7 @@ library
     , split
     , stm
     , streaming-commons
+    , streamly
     , string-conversions
     , system-linux-proc
     , tagged
diff --git a/integration/test/Test/NotificationsBenchmark.hs b/integration/test/Test/NotificationsBenchmark.hs
new file mode 100644
index 0000000000..479e0564d7
--- /dev/null
+++ b/integration/test/Test/NotificationsBenchmark.hs
@@ -0,0 +1,139 @@
+module Test.NotificationsBenchmark where
+
+import API.Brig
+import API.BrigCommon
+import API.Common
+import API.GundeckInternal
+import Control.Concurrent
+import Control.Monad.Codensity (Codensity (..))
+import Control.Monad.Reader (asks)
+import Control.Monad.Reader.Class (local)
+import Control.Retry
+import qualified Data.Map.Strict as Map
+import Data.String.Conversions (cs)
+import Data.Time
+import GHC.Conc (numCapabilities)
+import GHC.Stack
+import SetupHelpers
+import qualified Streamly.Data.Fold.Prelude as Fold
+import qualified Streamly.Data.Stream.Prelude as Stream
+import System.Random
+import qualified Test.Events as TestEvents
+import Testlib.Prekeys
+import Testlib.Prelude
+
+data TestRecipient = TestRecipient
+  { user :: Value,
+    clientIds :: [String]
+  }
+  deriving (Show)
+
+testBench :: (HasCallStack) => App ()
+testBench = do
+  shardingGroupCount <- asks (.shardingGroupCount)
+  shardingGroup <- asks (.shardingGroup)
+  maxUserNo <- asks (.maxUserNo)
+
+  -- Preparation
+  let parCfg = Stream.maxThreads (numCapabilities * 2) . Stream.ordered False
+      toMap = Fold.foldl' (\kv (k, v) -> Map.insert k v kv) Map.empty
+  -- Later, we only read from this map. Thus, it doesn't have to be thread-safe.
+  userMap :: Map Word TestRecipient <-
+    Stream.fromList [0 :: Word .. maxUserNo]
+      & Stream.filter ((shardingGroup ==) . (`mod` shardingGroupCount))
+      & Stream.parMapM parCfg (\i -> generateTestRecipient >>= \r -> pure (i, r))
+      & Stream.fold toMap
+
+  now <- liftIO getCurrentTime
+
+  -- TODO: To be replaced with real data from the file. (See
+  -- https://wearezeta.atlassian.net/wiki/spaces/PET/pages/2118680620/Simulating+production-like+data)
+  let fakeData = zip (plusDelta now <$> [0 :: Word ..]) (cycle [0 .. maxUserNo])
+
+  Stream.fromList fakeData
+    & Stream.filter (\(_t, uNo) -> (uNo `mod` shardingGroupCount) == shardingGroup)
+    & Stream.parMapM parCfg (\(t, uNo) -> waitForTimeStamp t >> sendAndReceive uNo userMap)
+    & Stream.fold Fold.drain
+
+waitForTimeStamp :: UTCTime -> App ()
+waitForTimeStamp timestamp = liftIO $ do
+  now <- getCurrentTime
+  when (now < timestamp)
+    $
+    -- Event comes from the simulated future: Wait here until now and timestamp are aligned.
+    let delta = diffTimeToMicroSeconds $ diffUTCTime timestamp now
+     in print ("Waiting " ++ show delta ++ " microseconds. (timestamp, now)" ++ show (timestamp, now))
+          >> threadDelay delta
+  where
+    diffTimeToMicroSeconds :: NominalDiffTime -> Int
+    diffTimeToMicroSeconds dt = floor @Double (realToFrac dt * 1_000_000)
+
+plusDelta :: UTCTime -> Word -> UTCTime
+plusDelta timestamp deltaMilliSeconds = addUTCTime (fromIntegral deltaMilliSeconds / 1000) timestamp
+
+sendAndReceive :: Word -> Map Word TestRecipient -> App ()
+sendAndReceive userNo userMap = do
+  print $ "pushing to user" ++ show userNo
+  let testRecipient = userMap Map.! (fromIntegral userNo)
+      alice = testRecipient.user
+
+  r <- recipient alice
+  payload :: Value <- toJSON <$> liftIO randomPayload
+  now <- liftIO $ getCurrentTime
+  let push =
+        object
+          [ "recipients" .= [r],
+            "payload"
+              .= [ object
+                     [ "foo" .= payload,
+                       "sent_at" .= now
+                     ]
+                 ]
+          ]
+
+  void $ postPush alice [push] >>= getBody 200
+
+  messageDeliveryTimeout <- asks $ fromIntegral . (.maxDeliveryDelay)
+  forM_ (testRecipient.clientIds) $ \(cid :: String) ->
+    runCodensity (TestEvents.createEventsWebSocket alice (Just cid)) $ \ws -> do
+      -- TODO: Tweak this value to the least acceptable event delivery duration
+      local (setTimeoutTo messageDeliveryTimeout) $ TestEvents.assertFindsEvent ws $ \e -> do
+        receivedAt <- liftIO getCurrentTime
+        sentAt :: UTCTime <- (e %. "payload.sent_at" >>= asByteString) <&> fromJust . decode . cs
+        print $ "Message sent/receive delta: " ++ show (diffUTCTime receivedAt sentAt)
+
+        e %. "payload" `shouldMatch` [object ["foo" .= payload]]
+  where
+    -- \| Generate a random string with random length up to 2048 bytes
+    randomPayload :: IO String
+    randomPayload =
+      -- Measured with
+      -- `kubectl exec --namespace databases -it gundeck-gundeck-eks-eu-west-1a-sts-0 -- sh -c 'cqlsh -e "select  blobAsText(payload) from gundeck.notifications LIMIT 5000;" ' | sed 's/^[ \t]*//;s/[ \t]*$//' | wc`
+      let len :: Int = 884 -- measured in prod
+       in mapM (\_ -> randomRIO ('\32', '\126')) [1 .. len] -- printable ASCII
+
+setTimeoutTo :: Int -> Env -> Env
+setTimeoutTo tSecs env = env {timeOutSeconds = tSecs}
+
+generateTestRecipient :: (HasCallStack) => App TestRecipient
+generateTestRecipient = do
+  print "generateTestRecipient"
+  user <- recover $ (randomUser OwnDomain def)
+  r <- randomRIO @Word (1, 8)
+  clientIds <- forM [0 .. r] $ \_ -> do
+    client <-
+      recover
+        $ addClient
+          user
+          def
+            { acapabilities = Just ["consumable-notifications"],
+              prekeys = Just $ take 10 somePrekeysRendered,
+              lastPrekey = Just $ head someLastPrekeysRendered
+            }
+        >>= getJSON 201
+    objId client
+
+  pure $ TestRecipient user clientIds
+  where
+    recover :: App a -> App a
+    recover = recoverAll (limitRetriesByCumulativeDelay 300 (exponentialBackoff 1_000_000)) . const
diff --git a/integration/test/Testlib/Cannon.hs b/integration/test/Testlib/Cannon.hs
index 45093c3e25..9a4aad779b 100644
--- a/integration/test/Testlib/Cannon.hs
+++ b/integration/test/Testlib/Cannon.hs
@@ -39,6 +39,8 @@ module Testlib.Cannon
     printAwaitAtLeastResult,
     waitForResponse,
     assertNoEvent,
+    -- This should never be merged!
+    connect,
   )
 where
 
diff --git a/integration/test/Testlib/Env.hs b/integration/test/Testlib/Env.hs
index 67a90228ad..7638e04608 100644
--- a/integration/test/Testlib/Env.hs
+++ b/integration/test/Testlib/Env.hs
@@ -62,8 +62,8 @@ serviceHostPort m Stern = m.stern
 serviceHostPort m FederatorInternal = m.federatorInternal
 serviceHostPort m WireServerEnterprise = m.wireServerEnterprise
 
-mkGlobalEnv :: FilePath -> Codensity IO GlobalEnv
-mkGlobalEnv cfgFile = do
+mkGlobalEnv :: FilePath -> Word -> Codensity IO GlobalEnv
+mkGlobalEnv cfgFile shardingGroup = do
   eith <- liftIO $ Yaml.decodeFileEither cfgFile
   intConfig <- liftIO $ case eith of
     Left err -> do
@@ -145,7 +145,11 @@ mkGlobalEnv cfgFile = do
         gDNSMockServerConfig = intConfig.dnsMockServer,
         gCellsEventQueue = intConfig.cellsEventQueue,
         gCellsEventWatchersLock,
-        gCellsEventWatchers
+        gCellsEventWatchers,
+        gShardingGroupCount = intConfig.shardingGroupCount,
+        gShardingGroup = shardingGroup,
+        gMaxUserNo = intConfig.maxUserNo,
+        gMaxDeliveryDelay = intConfig.maxDeliveryDelay
       }
   where
     createSSLContext :: Maybe FilePath -> IO (Maybe OpenSSL.SSLContext)
@@ -185,7 +189,9 @@ mkEnv currentTestName ge = do
           -- those domains.
           apiVersionByDomain =
             Map.fromList
-              [ (gFederationV0Domain ge, 4),
+              [ (gDomain1 ge, 11),
+                (gDomain2 ge, 11),
+                (gFederationV0Domain ge, 4),
                 (gFederationV1Domain ge, 5),
                 (gFederationV2Domain ge, 8)
               ],
@@ -201,7 +207,11 @@ mkEnv currentTestName ge = do
           dnsMockServerConfig = ge.gDNSMockServerConfig,
           cellsEventQueue = ge.gCellsEventQueue,
           cellsEventWatchersLock = ge.gCellsEventWatchersLock,
-          cellsEventWatchers = ge.gCellsEventWatchers
+          cellsEventWatchers = ge.gCellsEventWatchers,
+          shardingGroupCount = ge.gShardingGroupCount,
+          shardingGroup = ge.gShardingGroup,
+          maxUserNo = ge.gMaxUserNo,
+          maxDeliveryDelay = ge.gMaxDeliveryDelay
         }
 
 allCiphersuites :: [Ciphersuite]
diff --git a/integration/test/Testlib/Options.hs b/integration/test/Testlib/Options.hs
index f109e13d8f..2b56256eeb 100644
--- a/integration/test/Testlib/Options.hs
+++ b/integration/test/Testlib/Options.hs
@@ -27,7 +27,8 @@ data TestOptions = TestOptions
     excludeTests :: [String],
     listTests :: Bool,
     xmlReport :: Maybe FilePath,
-    configFile :: String
+    configFile :: String,
+    shardingGroup :: Word
   }
 
 parser :: Parser TestOptions
@@ -64,6 +65,13 @@ parser =
           <> help "Use configuration FILE"
           <> value "services/integration.yaml"
       )
+    <*> option
+      auto
+      ( long "sharding-group"
+          <> short 's'
+          <> help "The sharding group of this instance"
+          <> value 0
+      )
 
 optInfo :: ParserInfo TestOptions
 optInfo =
diff --git a/integration/test/Testlib/Run.hs b/integration/test/Testlib/Run.hs
index 1ae1ddf06d..43667a034a 100644
--- a/integration/test/Testlib/Run.hs
+++ b/integration/test/Testlib/Run.hs
@@ -22,35 +22,21 @@ import Control.Exception as E
 import Control.Monad
 import Control.Monad.Codensity
 import Control.Monad.IO.Class
-import Control.Monad.Reader.Class (asks)
-import Data.Default
 import Data.Foldable
 import Data.Function
 import Data.Functor
 import Data.List
 import Data.Maybe (fromMaybe)
-import Data.String (IsString (fromString))
-import Data.String.Conversions (cs)
-import Data.Text (Text)
-import qualified Data.Text as T
 import Data.Time
-import qualified Data.Yaml as Yaml
-import Network.AMQP.Extended
-import Network.RabbitMqAdmin
 import RunAllTests
 import System.Directory
 import System.Environment
 import System.Exit
 import System.FilePath
-import System.IO.Temp (writeTempFile)
-import System.Process
 import Testlib.Assertions
 import Testlib.Env
-import Testlib.ModService (readAndUpdateConfig)
 import Testlib.Options
 import Testlib.Printing
-import Testlib.ResourcePool (acquireResources)
-import Testlib.RunServices (backendA, backendB)
 import Testlib.Types
 import Testlib.XML
 import Text.Printf
@@ -123,6 +109,7 @@ main = do
   opts <- getOptions
   let f = testFilter opts
       cfg = opts.configFile
+      shardingGroup = opts.shardingGroup
 
   allTests <- mkAllTests
   let tests =
@@ -132,10 +119,10 @@ main = do
             let qualifiedName = fromMaybe module_ (stripPrefix "Test." module_) <> "." <> name
              in (qualifiedName, summary, full, action)
 
-  if opts.listTests then doListTests tests else runTests tests opts.xmlReport cfg
+  if opts.listTests then doListTests tests else runTests tests opts.xmlReport cfg shardingGroup
 
-runTests :: [(String, x, y, App ())] -> Maybe FilePath -> FilePath -> IO ()
-runTests tests mXMLOutput cfg = do
+runTests :: [(String, x, y, App ())] -> Maybe FilePath -> FilePath -> Word -> IO ()
+runTests tests mXMLOutput cfg shardingGroup = do
   output <- newChan
   let displayOutput =
         readChan output >>= \case
@@ -143,12 +130,12 @@ runTests tests mXMLOutput cfg = do
           Nothing -> pure ()
   let writeOutput = writeChan output . Just
 
-  runCodensity (mkEnvs cfg) $ \(genv, env) ->
+  runCodensity (mkEnvs cfg) $ \(genv, _env) ->
     withAsync displayOutput $ \displayThread -> do
       -- Although migrations are run on service start up we are running them here before
       -- to prevent race conditions between brig and galley
       -- which cause flakiness and can make the complete test suite fail
-      runAppWithEnv env runMigrations
+      -- runAppWithEnv env runMigrations
       -- Currently 4 seems to be stable, more seems to create more timeouts.
       report <- fmap mconcat $ pooledForConcurrentlyN 4 tests $ \(qname, _, _, action) -> do
         timestamp <- getCurrentTime
@@ -172,7 +159,7 @@ runTests tests mXMLOutput cfg = do
             pure (TestSuiteReport [TestCaseReport qname TestSuccess tm])
       writeChan output Nothing
       wait displayThread
-      deleteFederationV0AndV1Queues genv
+      -- deleteFederationV0AndV1Queues genv
       printReport report
       mapM_ (saveXMLReport report) mXMLOutput
       when (any (\testCase -> testCase.result /= TestSuccess) report.cases) $
@@ -180,62 +167,62 @@ runTests tests mXMLOutput cfg = do
   where
     mkEnvs :: FilePath -> Codensity IO (GlobalEnv, Env)
     mkEnvs fp = do
-      g <- mkGlobalEnv fp
+      g <- mkGlobalEnv fp shardingGroup
       e <- mkEnv Nothing g
       pure (g, e)
 
-runMigrations :: App ()
-runMigrations = do
-  cwdBase <- asks (.servicesCwdBase)
-  let brig = "brig"
-  let (cwd, exe) = case cwdBase of
-        Nothing -> (Nothing, brig)
-        Just dir ->
-          (Just (dir </> brig), "../../dist" </> brig)
-  getConfig <- readAndUpdateConfig def backendA Brig
-  config <- liftIO getConfig
-  tempFile <- liftIO $ writeTempFile "/tmp" "brig-migrations.yaml" (cs $ Yaml.encode config)
-  dynDomains <- asks (.dynamicDomains)
-  pool <- asks (.resourcePool)
-  lowerCodensity $ do
-    resources <- acquireResources (length dynDomains) pool
-    let dbnames = [backendA.berPostgresqlDBName, backendB.berPostgresqlDBName] <> map (.berPostgresqlDBName) resources
-    for_ dbnames $ runMigration exe tempFile cwd
-    liftIO $ putStrLn "Postgres migrations finished"
-  where
-    runMigration :: (MonadIO m) => FilePath -> FilePath -> Maybe FilePath -> String -> m ()
-    runMigration exe tempFile cwd dbname = do
-      let cp = (proc exe ["-c", tempFile, "migrate-postgres", "--dbname", dbname]) {cwd}
-      (_, _, _, ph) <- liftIO $ createProcess cp
-      void $ liftIO $ waitForProcess ph
-
-deleteFederationV0AndV1Queues :: GlobalEnv -> IO ()
-deleteFederationV0AndV1Queues env = do
-  let testDomains = env.gDomain1 : env.gDomain2 : env.gDynamicDomains
-  putStrLn "Attempting to delete federation V0 queues..."
-  (mV0User, mV0Pass) <- readCredsFromEnvWithSuffix "V0"
-  fromMaybe (putStrLn "No or incomplete credentials for fed V0 RabbitMQ") $
-    deleteFederationQueues testDomains env.gRabbitMQConfigV0 <$> mV0User <*> mV0Pass
-
-  putStrLn "Attempting to delete federation V1 queues..."
-  (mV1User, mV1Pass) <- readCredsFromEnvWithSuffix "V1"
-  fromMaybe (putStrLn "No or incomplete credentials for fed V1 RabbitMQ") $
-    deleteFederationQueues testDomains env.gRabbitMQConfigV1 <$> mV1User <*> mV1Pass
-  where
-    readCredsFromEnvWithSuffix :: String -> IO (Maybe Text, Maybe Text)
-    readCredsFromEnvWithSuffix suffix =
-      (,)
-        <$> (fmap fromString <$> lookupEnv ("RABBITMQ_USERNAME_" <> suffix))
-        <*> (fmap fromString <$> lookupEnv ("RABBITMQ_PASSWORD_" <> suffix))
-
-deleteFederationQueues :: [String] -> RabbitMqAdminOpts -> Text -> Text -> IO ()
-deleteFederationQueues testDomains opts username password = do
-  client <- mkRabbitMqAdminClientEnvWithCreds opts username password
-  for_ testDomains $ \domain -> do
-    page <- client.listQueuesByVHost opts.vHost (fromString $ "^backend-notifications\\." <> domain <> "$") True 100 1
-    for_ page.items $ \queue -> do
-      putStrLn $ "Deleting queue " <> T.unpack queue.name
-      void $ deleteQueue client opts.vHost queue.name
+-- runMigrations :: App ()
+-- runMigrations = do
+--   cwdBase <- asks (.servicesCwdBase)
+--   let brig = "brig"
+--   let (cwd, exe) = case cwdBase of
+--         Nothing -> (Nothing, brig)
+--         Just dir ->
+--           (Just (dir </> brig), "../../dist" </> brig)
+--   getConfig <- readAndUpdateConfig def backendA Brig
+--   config <- liftIO getConfig
+--   tempFile <- liftIO $ writeTempFile "/tmp" "brig-migrations.yaml" (cs $ Yaml.encode config)
+--   dynDomains <- asks (.dynamicDomains)
+--   pool <- asks (.resourcePool)
+--   lowerCodensity $ do
+--     resources <- acquireResources (length dynDomains) pool
+--     let dbnames = [backendA.berPostgresqlDBName, backendB.berPostgresqlDBName] <> map (.berPostgresqlDBName) resources
+--     for_ dbnames $ runMigration exe tempFile cwd
+--     liftIO $ putStrLn "Postgres migrations finished"
+--   where
+--     runMigration :: (MonadIO m) => FilePath -> FilePath -> Maybe FilePath -> String -> m ()
+--     runMigration exe tempFile cwd dbname = do
+--       let cp = (proc exe ["-c", tempFile, "migrate-postgres", "--dbname", dbname]) {cwd}
+--       (_, _, _, ph) <- liftIO $ createProcess cp
+--       void $ liftIO $ waitForProcess ph
+
+-- deleteFederationV0AndV1Queues :: GlobalEnv -> IO ()
+-- deleteFederationV0AndV1Queues env = do
+--   let testDomains = env.gDomain1 : env.gDomain2 : env.gDynamicDomains
+--   putStrLn "Attempting to delete federation V0 queues..."
+--   (mV0User, mV0Pass) <- readCredsFromEnvWithSuffix "V0"
+--   fromMaybe (putStrLn "No or incomplete credentials for fed V0 RabbitMQ") $
+--     deleteFederationQueues testDomains env.gRabbitMQConfigV0 <$> mV0User <*> mV0Pass
+--
+--   putStrLn "Attempting to delete federation V1 queues..."
+--   (mV1User, mV1Pass) <- readCredsFromEnvWithSuffix "V1"
+--   fromMaybe (putStrLn "No or incomplete credentials for fed V1 RabbitMQ") $
+--     deleteFederationQueues testDomains env.gRabbitMQConfigV1 <$> mV1User <*> mV1Pass
+--   where
+--     readCredsFromEnvWithSuffix :: String -> IO (Maybe Text, Maybe Text)
+--     readCredsFromEnvWithSuffix suffix =
+--       (,)
+--         <$> (fmap fromString <$> lookupEnv ("RABBITMQ_USERNAME_" <> suffix))
+--         <*> (fmap fromString <$> lookupEnv ("RABBITMQ_PASSWORD_" <> suffix))
+--
+-- deleteFederationQueues :: [String] -> RabbitMqAdminOpts -> Text -> Text -> IO ()
+-- deleteFederationQueues testDomains opts username password = do
+--   client <- mkRabbitMqAdminClientEnvWithCreds opts username password
+--   for_ testDomains $ \domain -> do
+--     page <- client.listQueuesByVHost opts.vHost (fromString $ "^backend-notifications\\." <> domain <> "$") True 100 1
+--     for_ page.items $ \queue -> do
+--       putStrLn $ "Deleting queue " <> T.unpack queue.name
+--       void $ deleteQueue client opts.vHost queue.name
 
 doListTests :: [(String, String, String, x)] -> IO ()
 doListTests tests = for_ tests $ \(qname, _desc, _full, _) -> do
diff --git a/integration/test/Testlib/RunServices.hs b/integration/test/Testlib/RunServices.hs
index 4a9f6403d4..5fbcabc2e2 100644
--- a/integration/test/Testlib/RunServices.hs
+++ b/integration/test/Testlib/RunServices.hs
@@ -88,8 +88,10 @@ main = do
           let cp = proc "sh" (["-c", "exec \"$@\"", "--"] <> opts.runSubprocess)
           (_, _, _, ph) <- createProcess cp
           exitWith =<< waitForProcess ph
+      -- The shardingGroup only matters for the testBench test; probably not here.
+      shardingGroup = 0
 
-  runCodensity (mkGlobalEnv cfg >>= mkEnv Nothing) $ \env ->
+  runCodensity (mkGlobalEnv cfg shardingGroup >>= mkEnv Nothing) $ \env ->
     runAppWithEnv env
       $ lowerCodensity
       $ do
diff --git a/integration/test/Testlib/Types.hs b/integration/test/Testlib/Types.hs
index 29aa0b2b4b..99044af3c6 100644
--- a/integration/test/Testlib/Types.hs
+++ b/integration/test/Testlib/Types.hs
@@ -144,7 +144,11 @@ data GlobalEnv = GlobalEnv
     gDNSMockServerConfig :: DNSMockServerConfig,
     gCellsEventQueue :: String,
     gCellsEventWatchersLock :: MVar (),
-    gCellsEventWatchers :: IORef (Map String QueueWatcher)
+    gCellsEventWatchers :: IORef (Map String QueueWatcher),
+    gShardingGroupCount :: Word,
+    gShardingGroup :: Word,
+    gMaxUserNo :: Word,
+    gMaxDeliveryDelay :: Word
   }
 
 data IntegrationConfig = IntegrationConfig
@@ -160,7 +164,10 @@ data IntegrationConfig = IntegrationConfig
     rabbitmqV1 :: RabbitMqAdminOpts,
     cassandra :: CassandraConfig,
     dnsMockServer :: DNSMockServerConfig,
-    cellsEventQueue :: String
+    cellsEventQueue :: String,
+    shardingGroupCount :: Word,
+    maxUserNo :: Word,
+    maxDeliveryDelay :: Word
   }
   deriving (Show, Generic)
 
@@ -181,6 +188,9 @@ instance FromJSON IntegrationConfig where
         <*> o .: fromString "cassandra"
         <*> o .: fromString "dnsMockServer"
         <*> o .: fromString "cellsEventQueue"
+        <*> o .: fromString "shardingGroupCount"
+        <*> o .: fromString "maxUserNo"
+        <*> o .: fromString "maxDeliveryDelay"
 
 data ServiceMap = ServiceMap
   { brig :: HostPort,
@@ -271,7 +281,11 @@ data Env = Env
     dnsMockServerConfig :: DNSMockServerConfig,
     cellsEventQueue :: String,
     cellsEventWatchersLock :: MVar (),
-    cellsEventWatchers :: IORef (Map String QueueWatcher)
+    cellsEventWatchers :: IORef (Map String QueueWatcher),
+    shardingGroupCount :: Word,
+    shardingGroup :: Word,
+    maxUserNo :: Word,
+    maxDeliveryDelay :: Word
   }
 
 data Response = Response
@@ -446,7 +460,7 @@ hoistCodensity m = Codensity $ \k -> do
 getServiceMap :: (HasCallStack) => String -> App ServiceMap
 getServiceMap fedDomain = do
   env <- ask
-  assertJust ("Could not find service map for federation domain: " <> fedDomain) (Map.lookup fedDomain env.serviceMap)
+  assertJust ("Could not find service map for federation domain: " <> fedDomain <> " in " <> show (Map.keys env.serviceMap)) (Map.lookup fedDomain env.serviceMap)
 
 getMLSState :: App MLSState
 getMLSState = do
diff --git a/services/integration.yaml b/services/integration.yaml
index 427aa761d1..9ec920a603 100644
--- a/services/integration.yaml
+++ b/services/integration.yaml
@@ -330,3 +330,7 @@ integrationTestHostName: "localhost"
 additionalElasticSearch: https://localhost:9201
 
 cellsEventQueue: cells_events
+
+shardingGroupCount: 1
+maxUserNo: 1000
+maxDeliveryDelay: 120