diff --git a/keyserver/src/push/rescind.js b/keyserver/src/push/rescind.js
--- a/keyserver/src/push/rescind.js
+++ b/keyserver/src/push/rescind.js
@@ -309,7 +309,7 @@
   platformDetails: PlatformDetails,
   devices: $ReadOnlyArray<NotificationTargetDevice>,
 ): Promise<$ReadOnlyArray<TargetedAPNsNotification>> {
-  threadID = validateOutput(platformDetails, tID, threadID);
+  threadID = await validateOutput(platformDetails, tID, threadID);
   const { codeVersion } = platformDetails;
 
   const notification = new apn.Notification();
@@ -356,7 +356,7 @@
   platformDetails: PlatformDetails,
   devices: $ReadOnlyArray<NotificationTargetDevice>,
 ): Promise<$ReadOnlyArray<TargetedAndroidNotification>> {
-  threadID = validateOutput(platformDetails, tID, threadID);
+  threadID = await validateOutput(platformDetails, tID, threadID);
   const { codeVersion } = platformDetails;
 
   const notification = {
diff --git a/keyserver/src/push/send.js b/keyserver/src/push/send.js
--- a/keyserver/src/push/send.js
+++ b/keyserver/src/push/send.js
@@ -907,7 +907,7 @@
   inputData: APNsNotifInputData,
   devices: $ReadOnlyArray<NotificationTargetDevice>,
 ): Promise<$ReadOnlyArray<TargetedAPNsNotification>> {
-  const convertedData = validateOutput(
+  const convertedData = await validateOutput(
     inputData.platformDetails,
     apnsNotifInputDataValidator,
     inputData,
@@ -1087,7 +1087,7 @@
   inputData: AndroidNotifInputData,
   devices: $ReadOnlyArray<NotificationTargetDevice>,
 ): Promise<$ReadOnlyArray<TargetedAndroidNotification>> {
-  const convertedData = validateOutput(
+  const convertedData = await validateOutput(
     inputData.platformDetails,
     androidNotifInputDataValidator,
     inputData,
@@ -1241,7 +1241,7 @@
   inputData: WebNotifInputData,
   devices: $ReadOnlyArray<NotificationTargetDevice>,
 ): Promise<$ReadOnlyArray<TargetedWebNotification>> {
-  const convertedData = validateOutput(
+  const convertedData = await validateOutput(
     inputData.platformDetails,
     webNotifInputDataValidator,
     inputData,
@@ -1283,7 +1283,7 @@
   devices: $ReadOnlyArray<NotificationTargetDevice>,
   inputData: WNSNotifInputData,
 ): Promise<$ReadOnlyArray<TargetedWNSNotification>> {
-  const convertedData = validateOutput(
+  const convertedData = await validateOutput(
     inputData.platformDetails,
     wnsNotifInputDataValidator,
     inputData,
diff --git a/keyserver/src/responders/handlers.js b/keyserver/src/responders/handlers.js
--- a/keyserver/src/responders/handlers.js
+++ b/keyserver/src/responders/handlers.js
@@ -44,7 +44,11 @@
     responder: async (viewer, input) => {
       const request = await validateInput(viewer, inputValidator, input);
       const result = await responder(viewer, request);
-      return validateOutput(viewer.platformDetails, outputValidator, result);
+      return await validateOutput(
+        viewer.platformDetails,
+        outputValidator,
+        result,
+      );
     },
     requiredPolicies,
   };
diff --git a/keyserver/src/responders/redux-state-responders.js b/keyserver/src/responders/redux-state-responders.js
--- a/keyserver/src/responders/redux-state-responders.js
+++ b/keyserver/src/responders/redux-state-responders.js
@@ -44,7 +44,7 @@
 import { ServerError } from 'lib/utils/errors.js';
 import { promiseAll } from 'lib/utils/promises.js';
 import { urlInfoValidator } from 'lib/utils/url-utils.js';
-import { tShape, ashoatKeyserverID, tID } from 'lib/utils/validation-utils.js';
+import { tShape, tID } from 'lib/utils/validation-utils.js';
 import type {
   InitialReduxStateRequest,
   ExcludedData,
@@ -64,6 +64,7 @@
 import { getWebPushConfig } from '../push/providers.js';
 import { setNewSession } from '../session/cookies.js';
 import { Viewer } from '../session/viewer.js';
+import { thisKeyserverID } from '../user/identity.js';
 
 const excludedDataValidator: TInterface<ExcludedData> = tShape<ExcludedData>({
   threadStore: t.maybe(t.Bool),
@@ -190,24 +191,26 @@
       { threadInfos },
       { rawMessageInfos, truncationStatuses },
       hasNotAcknowledgedPolicies,
+      keyserverID,
     ] = await Promise.all([
       threadInfoPromise,
       messageInfoPromise,
       hasNotAcknowledgedPoliciesPromise,
+      thisKeyserverID(),
     ]);
     if (hasNotAcknowledgedPolicies) {
       return {
         messages: {},
         threads: {},
         local: {},
-        currentAsOf: { [ashoatKeyserverID]: 0 },
+        currentAsOf: { [keyserverID]: 0 },
       };
     }
     const { messageStore: freshStore } = freshMessageStore(
       rawMessageInfos,
       truncationStatuses,
       {
-        [ashoatKeyserverID]: mostRecentMessageTimestamp(
+        [keyserverID]: mostRecentMessageTimestamp(
           rawMessageInfos,
           serverUpdatesCurrentAsOf,
         ),
diff --git a/keyserver/src/shared/state-sync/current-user-state-sync-spec.js b/keyserver/src/shared/state-sync/current-user-state-sync-spec.js
--- a/keyserver/src/shared/state-sync/current-user-state-sync-spec.js
+++ b/keyserver/src/shared/state-sync/current-user-state-sync-spec.js
@@ -22,7 +22,7 @@
   },
   async fetchServerInfosHash(viewer: Viewer) {
     const info = await fetch(viewer);
-    return getHash(info);
+    return await getHash(info);
   },
   getServerInfosHash: getHash,
   getServerInfoHash: getHash,
@@ -33,6 +33,11 @@
   return fetchCurrentUserInfo(viewer);
 }
 
-function getHash(currentUserInfo: CurrentUserInfo) {
-  return hash(validateOutput(null, currentUserInfoValidator, currentUserInfo));
+async function getHash(currentUserInfo: CurrentUserInfo) {
+  const output = await validateOutput(
+    null,
+    currentUserInfoValidator,
+    currentUserInfo,
+  );
+  return hash(output);
 }
diff --git a/keyserver/src/shared/state-sync/entries-state-sync-spec.js b/keyserver/src/shared/state-sync/entries-state-sync-spec.js
--- a/keyserver/src/shared/state-sync/entries-state-sync-spec.js
+++ b/keyserver/src/shared/state-sync/entries-state-sync-spec.js
@@ -35,7 +35,7 @@
   },
   async fetchServerInfosHash(viewer: Viewer, ids?: $ReadOnlySet<string>) {
     const info = await fetch(viewer, ids);
-    return getServerInfosHash(info);
+    return await getServerInfosHash(info);
   },
   getServerInfosHash,
   getServerInfoHash,
@@ -51,10 +51,12 @@
   return serverEntryInfosObject(entriesResult.rawEntryInfos);
 }
 
-function getServerInfosHash(infos: RawEntryInfos) {
-  return combineUnorderedHashes(values(infos).map(getServerInfoHash));
+async function getServerInfosHash(infos: RawEntryInfos) {
+  const results = await Promise.all(values(infos).map(getServerInfoHash));
+  return combineUnorderedHashes(results);
 }
 
-function getServerInfoHash(info: RawEntryInfo) {
-  return hash(validateOutput(null, rawEntryInfoValidator, info));
+async function getServerInfoHash(info: RawEntryInfo) {
+  const output = await validateOutput(null, rawEntryInfoValidator, info);
+  return hash(output);
 }
diff --git a/keyserver/src/shared/state-sync/state-sync-spec.js b/keyserver/src/shared/state-sync/state-sync-spec.js
--- a/keyserver/src/shared/state-sync/state-sync-spec.js
+++ b/keyserver/src/shared/state-sync/state-sync-spec.js
@@ -20,7 +20,7 @@
     viewer: Viewer,
     ids?: $ReadOnlySet<string>,
   ) => Promise<number>,
-  +getServerInfosHash: (infos: Infos) => number,
-  +getServerInfoHash: (info: Info) => number,
+  +getServerInfosHash: (infos: Infos) => Promise<number>,
+  +getServerInfoHash: (info: Info) => Promise<number>,
   ...StateSyncSpec<Infos, Info, Inconsistencies>,
 };
diff --git a/keyserver/src/shared/state-sync/threads-state-sync-spec.js b/keyserver/src/shared/state-sync/threads-state-sync-spec.js
--- a/keyserver/src/shared/state-sync/threads-state-sync-spec.js
+++ b/keyserver/src/shared/state-sync/threads-state-sync-spec.js
@@ -28,7 +28,7 @@
   },
   async fetchServerInfosHash(viewer: Viewer, ids?: $ReadOnlySet<string>) {
     const infos = await fetch(viewer, ids);
-    return getServerInfosHash(infos);
+    return await getServerInfosHash(infos);
   },
   getServerInfosHash,
   getServerInfoHash,
@@ -41,10 +41,12 @@
   return result.threadInfos;
 }
 
-function getServerInfosHash(infos: MixedRawThreadInfos) {
-  return combineUnorderedHashes(values(infos).map(getServerInfoHash));
+async function getServerInfosHash(infos: MixedRawThreadInfos) {
+  const results = await Promise.all(values(infos).map(getServerInfoHash));
+  return combineUnorderedHashes(results);
 }
 
-function getServerInfoHash(info: LegacyRawThreadInfo | RawThreadInfo) {
-  return hash(validateOutput(null, mixedRawThreadInfoValidator, info));
+async function getServerInfoHash(info: LegacyRawThreadInfo | RawThreadInfo) {
+  const output = await validateOutput(null, mixedRawThreadInfoValidator, info);
+  return hash(output);
 }
diff --git a/keyserver/src/shared/state-sync/users-state-sync-spec.js b/keyserver/src/shared/state-sync/users-state-sync-spec.js
--- a/keyserver/src/shared/state-sync/users-state-sync-spec.js
+++ b/keyserver/src/shared/state-sync/users-state-sync-spec.js
@@ -24,7 +24,7 @@
   },
   async fetchServerInfosHash(viewer: Viewer, ids?: $ReadOnlySet<string>) {
     const infos = await fetch(viewer, ids);
-    return getServerInfosHash(infos);
+    return await getServerInfosHash(infos);
   },
   getServerInfosHash,
   getServerInfoHash,
@@ -39,10 +39,12 @@
   return fetchKnownUserInfos(viewer);
 }
 
-function getServerInfosHash(infos: UserInfos) {
-  return combineUnorderedHashes(values(infos).map(getServerInfoHash));
+async function getServerInfosHash(infos: UserInfos) {
+  const results = await Promise.all(values(infos).map(getServerInfoHash));
+  return combineUnorderedHashes(results);
 }
 
-function getServerInfoHash(info: UserInfo) {
-  return hash(validateOutput(null, userInfoValidator, info));
+async function getServerInfoHash(info: UserInfo) {
+  const output = await validateOutput(null, userInfoValidator, info);
+  return hash(output);
 }
diff --git a/keyserver/src/socket/session-utils.js b/keyserver/src/socket/session-utils.js
--- a/keyserver/src/socket/session-utils.js
+++ b/keyserver/src/socket/session-utils.js
@@ -478,7 +478,9 @@
         ) {
           // We have a type error here because Flow has no way to determine that
           // spec and infos are matched up
-          hashValue = spec.getServerInfoHash((iterableInfos[infoID]: any));
+          hashValue = await spec.getServerInfoHash(
+            (iterableInfos[infoID]: any),
+          );
         } else {
           hashValue = hash(iterableInfos[infoID]);
         }
diff --git a/keyserver/src/socket/socket.js b/keyserver/src/socket/socket.js
--- a/keyserver/src/socket/socket.js
+++ b/keyserver/src/socket/socket.js
@@ -379,7 +379,7 @@
     }
 
     const { viewer } = this;
-    const validatedMessage = validateOutput(
+    const validatedMessage = await validateOutput(
       viewer?.platformDetails,
       serverServerSocketMessageValidator,
       message,
@@ -411,7 +411,7 @@
       payload: compressionResult.result,
     };
 
-    const validatedCompressedMessage = validateOutput(
+    const validatedCompressedMessage = await validateOutput(
       viewer?.platformDetails,
       serverServerSocketMessageValidator,
       compressedMessage,
diff --git a/keyserver/src/uploads/uploads.js b/keyserver/src/uploads/uploads.js
--- a/keyserver/src/uploads/uploads.js
+++ b/keyserver/src/uploads/uploads.js
@@ -102,7 +102,7 @@
     throw new ServerError('invalid_parameters');
   }
   const results = await createUploads(viewer, uploadInfos);
-  return validateOutput(
+  return await validateOutput(
     viewer.platformDetails,
     MultimediaUploadResultValidator,
     {
diff --git a/keyserver/src/user/checks.js b/keyserver/src/user/checks.js
--- a/keyserver/src/user/checks.js
+++ b/keyserver/src/user/checks.js
@@ -1,7 +1,11 @@
 // @flow
 
 import { getCommConfig } from 'lib/utils/comm-config.js';
-export type UserCredentials = { +username: string, +password: string };
+export type UserCredentials = {
+  +username: string,
+  +password: string,
+  +id?: string,
+};
 
 async function ensureUserCredentials() {
   const userCredentials = await getCommConfig<UserCredentials>({
diff --git a/keyserver/src/user/identity.js b/keyserver/src/user/identity.js
--- a/keyserver/src/user/identity.js
+++ b/keyserver/src/user/identity.js
@@ -2,6 +2,10 @@
 
 import type { QueryResults } from 'mysql';
 
+import { getCommConfig } from 'lib/utils/comm-config.js';
+import { ashoatKeyserverID } from 'lib/utils/validation-utils.js';
+
+import type { UserCredentials } from './checks.js';
 import { SQL, dbQuery } from '../database/database.js';
 
 const userIDMetadataKey = 'user_id';
@@ -34,6 +38,14 @@
   return { userId: userID, accessToken };
 }
 
+async function thisKeyserverID(): Promise<string> {
+  const userCredentials = await getCommConfig<UserCredentials>({
+    folder: 'secrets',
+    name: 'user_credentials',
+  });
+  return userCredentials?.id ?? ashoatKeyserverID;
+}
+
 function saveIdentityInfo(userInfo: IdentityInfo): Promise<QueryResults> {
   const updateQuery = SQL`
     REPLACE INTO metadata (name, data)
@@ -44,4 +56,4 @@
   return dbQuery(updateQuery);
 }
 
-export { fetchIdentityInfo, saveIdentityInfo };
+export { fetchIdentityInfo, thisKeyserverID, saveIdentityInfo };
diff --git a/keyserver/src/user/login.js b/keyserver/src/user/login.js
--- a/keyserver/src/user/login.js
+++ b/keyserver/src/user/login.js
@@ -7,6 +7,7 @@
 import { ServerError } from 'lib/utils/errors.js';
 import { retrieveAccountKeysSet } from 'lib/utils/olm-utils.js';
 
+import type { UserCredentials } from './checks.js';
 import {
   saveIdentityInfo,
   fetchIdentityInfo,
@@ -15,8 +16,6 @@
 import { getMessageForException } from '../responders/utils.js';
 import { fetchCallUpdateOlmAccount } from '../updaters/olm-account-updater.js';
 
-type UserCredentials = { +username: string, +password: string };
-
 // After register or login is successful
 function markKeysAsPublished(account: OlmAccount) {
   account.mark_prekey_as_published();
@@ -109,6 +108,9 @@
       fetchCallUpdateOlmAccount('content', markKeysAsPublished),
       fetchCallUpdateOlmAccount('notifications', markKeysAsPublished),
     ]);
+    if (userInfo.id && userInfo.id !== identity_info.userId) {
+      throw new Error('User id inconsistent with environment config');
+    }
     return identity_info;
   } catch (e) {
     console.warn('Failed to login user: ' + getMessageForException(e));
@@ -128,6 +130,9 @@
         fetchCallUpdateOlmAccount('content', markKeysAsPublished),
         fetchCallUpdateOlmAccount('notifications', markKeysAsPublished),
       ]);
+      if (userInfo.id && userInfo.id !== identity_info.userId) {
+        throw new Error('User id inconsistent with environment config');
+      }
       return identity_info;
     } catch (err) {
       console.warn('Failed to register user: ' + getMessageForException(err));
diff --git a/keyserver/src/utils/validation-utils.js b/keyserver/src/utils/validation-utils.js
--- a/keyserver/src/utils/validation-utils.js
+++ b/keyserver/src/utils/validation-utils.js
@@ -20,12 +20,12 @@
   tPlatform,
   tPlatformDetails,
   assertWithValidator,
-  ashoatKeyserverID,
 } from 'lib/utils/validation-utils.js';
 
 import { fetchNotAcknowledgedPolicies } from '../fetchers/policy-acknowledgment-fetchers.js';
 import { verifyClientSupported } from '../session/version.js';
 import type { Viewer } from '../session/viewer.js';
+import { thisKeyserverID } from '../user/identity.js';
 
 async function validateInput<T>(
   viewer: Viewer,
@@ -37,6 +37,8 @@
   }
   const convertedInput = checkInputValidator(inputValidator, input);
 
+  const keyserverID = await thisKeyserverID();
+
   if (
     hasMinStateVersion(viewer.platformDetails, {
       native: 43,
@@ -45,7 +47,7 @@
   ) {
     try {
       return convertClientIDsToServerIDs(
-        ashoatKeyserverID,
+        keyserverID,
         inputValidator,
         convertedInput,
       );
@@ -57,11 +59,11 @@
   return convertedInput;
 }
 
-function validateOutput<T>(
+async function validateOutput<T>(
   platformDetails: ?PlatformDetails,
   outputValidator: TType<T>,
   data: T,
-): T {
+): Promise<T> {
   if (!outputValidator.is(data)) {
     console.trace(
       'Output validation failed, validator is:',
@@ -70,17 +72,15 @@
     return data;
   }
 
+  const keyserverID = await thisKeyserverID();
+
   if (
     hasMinStateVersion(platformDetails, {
       native: 43,
       web: 3,
     })
   ) {
-    return convertServerIDsToClientIDs(
-      ashoatKeyserverID,
-      outputValidator,
-      data,
-    );
+    return convertServerIDsToClientIDs(keyserverID, outputValidator, data);
   }
 
   return data;