diff --git a/service/src/main/java/org/whispersystems/textsecuregcm/controllers/MessageController.java b/service/src/main/java/org/whispersystems/textsecuregcm/controllers/MessageController.java
index 37e2999c2..ae21def9b 100644
--- a/service/src/main/java/org/whispersystems/textsecuregcm/controllers/MessageController.java
+++ b/service/src/main/java/org/whispersystems/textsecuregcm/controllers/MessageController.java
@@ -25,6 +25,8 @@ import java.time.Duration;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Base64;
+import java.util.Collection;
+import java.util.Collections;
 import java.util.HashSet;
 import java.util.LinkedList;
 import java.util.List;
@@ -362,26 +364,34 @@ public class MessageController {
         }));
     checkAccessKeys(accessKeys, uuidToAccountMap);
 
-    List<AccountMismatchedDevices> accountMismatchedDevices = new ArrayList<>();
-    List<AccountStaleDevices> accountStaleDevices = new ArrayList<>();
-    for (Account account : uuidToAccountMap.values()) {
-      Set<Long> deviceIds = Arrays.stream(multiRecipientMessage.getRecipients())
-          .filter(recipient -> recipient.getUuid().equals(account.getUuid()))
-          .map(Recipient::getDeviceId)
-          .collect(Collectors.toSet());
-      Stream<Pair<Long, Integer>> deviceIdAndRegistrationIdStream = Arrays.stream(multiRecipientMessage.getRecipients())
-          .filter(recipient -> recipient.getUuid().equals(account.getUuid()))
-          .map(recipient -> new Pair<>(recipient.getDeviceId(), recipient.getRegistrationId()));
+    final Map<Account, HashSet<Pair<Long, Integer>>> accountToDeviceIdAndRegistrationIdMap =
+        Arrays
+            .stream(multiRecipientMessage.getRecipients())
+            .collect(Collectors.toMap(
+                recipient -> uuidToAccountMap.get(recipient.getUuid()),
+                recipient -> new HashSet<>(
+                    Collections.singletonList(new Pair<>(recipient.getDeviceId(), recipient.getRegistrationId()))),
+                (a, b) -> {
+                  a.addAll(b);
+                  return a;
+                }
+            ));
+
+    Collection<AccountMismatchedDevices> accountMismatchedDevices = new ArrayList<>();
+    Collection<AccountStaleDevices> accountStaleDevices = new ArrayList<>();
+    uuidToAccountMap.values().forEach(account -> {
+      final Set<Pair<Long, Integer>> deviceIdAndRegistrationIdSet = accountToDeviceIdAndRegistrationIdMap.get(account);
+      final Set<Long> deviceIds = deviceIdAndRegistrationIdSet.stream().map(Pair::first).collect(Collectors.toSet());
       try {
         validateCompleteDeviceList(account, deviceIds, false);
-        validateRegistrationIds(account, deviceIdAndRegistrationIdStream);
+        validateRegistrationIds(account, deviceIdAndRegistrationIdSet.stream());
       } catch (MismatchedDevicesException e) {
         accountMismatchedDevices.add(new AccountMismatchedDevices(account.getUuid(),
             new MismatchedDevices(e.getMissingDevices(), e.getExtraDevices())));
       } catch (StaleDevicesException e) {
         accountStaleDevices.add(new AccountStaleDevices(account.getUuid(), new StaleDevices(e.getStaleDevices())));
       }
-    }
+    });
     if (!accountMismatchedDevices.isEmpty()) {
       return Response
           .status(409)