diff --git a/keyserver/src/responders/activity-responders.js b/keyserver/src/responders/activity-responders.js
--- a/keyserver/src/responders/activity-responders.js
+++ b/keyserver/src/responders/activity-responders.js
@@ -29,16 +29,15 @@
   }),
 );
 
-const inputValidator = tShape({
+const inputValidator = tShape<UpdateActivityRequest>({
   updates: activityUpdatesInputValidator,
 });
 
 async function updateActivityResponder(
   viewer: Viewer,
-  input: any,
+  input: mixed,
 ): Promise<UpdateActivityResult> {
-  const request: UpdateActivityRequest = input;
-  await validateInput(viewer, inputValidator, request);
+  const request = await validateInput(viewer, inputValidator, input);
   const result = await activityUpdater(viewer, request);
   return validateOutput(viewer, updateActivityResultValidator, result);
 }
@@ -50,10 +49,13 @@
 });
 async function threadSetUnreadStatusResponder(
   viewer: Viewer,
-  input: any,
+  input: mixed,
 ): Promise<SetThreadUnreadStatusResult> {
-  const request: SetThreadUnreadStatusRequest = input;
-  await validateInput(viewer, setThreadUnreadStatusValidator, request);
+  const request = await validateInput(
+    viewer,
+    setThreadUnreadStatusValidator,
+    input,
+  );
 
   const result = await setThreadUnreadStatus(viewer, request);
   return validateOutput(viewer, setThreadUnreadStatusResult, result);
diff --git a/keyserver/src/responders/entry-responders.js b/keyserver/src/responders/entry-responders.js
--- a/keyserver/src/responders/entry-responders.js
+++ b/keyserver/src/responders/entry-responders.js
@@ -136,10 +136,14 @@
 
 async function entryFetchResponder(
   viewer: Viewer,
-  input: any,
+  input: mixed,
 ): Promise<FetchEntryInfosResponse> {
-  await validateInput(viewer, entryQueryInputValidator, input);
-  const request = normalizeCalendarQuery(input);
+  const inputQuery = await validateInput(
+    viewer,
+    entryQueryInputValidator,
+    input,
+  );
+  const request = normalizeCalendarQuery(inputQuery);
 
   await verifyCalendarQueryThreadIDs(request);
 
@@ -150,9 +154,10 @@
   });
 }
 
-const entryRevisionHistoryFetchInputValidator = tShape({
-  id: tID,
-});
+const entryRevisionHistoryFetchInputValidator =
+  tShape<FetchEntryRevisionInfosRequest>({
+    id: tID,
+  });
 
 export const fetchEntryRevisionInfosResultValidator: TInterface<FetchEntryRevisionInfosResult> =
   tShape<FetchEntryRevisionInfosResult>({
@@ -161,10 +166,13 @@
 
 async function entryRevisionFetchResponder(
   viewer: Viewer,
-  input: any,
+  input: mixed,
 ): Promise<FetchEntryRevisionInfosResult> {
-  const request: FetchEntryRevisionInfosRequest = input;
-  await validateInput(viewer, entryRevisionHistoryFetchInputValidator, request);
+  const request = await validateInput(
+    viewer,
+    entryRevisionHistoryFetchInputValidator,
+    input,
+  );
   const entryHistory = await fetchEntryRevisionInfo(viewer, request.id);
   const response = { result: entryHistory };
   return validateOutput(
@@ -174,7 +182,7 @@
   );
 }
 
-const createEntryRequestInputValidator = tShape({
+const createEntryRequestInputValidator = tShape<CreateEntryRequest>({
   text: t.String,
   sessionID: t.maybe(t.String),
   timestamp: t.Number,
@@ -193,15 +201,18 @@
 
 async function entryCreationResponder(
   viewer: Viewer,
-  input: any,
+  input: mixed,
 ): Promise<SaveEntryResponse> {
-  const request: CreateEntryRequest = input;
-  await validateInput(viewer, createEntryRequestInputValidator, request);
+  const request = await validateInput(
+    viewer,
+    createEntryRequestInputValidator,
+    input,
+  );
   const response = await createEntry(viewer, request);
   return validateOutput(viewer, saveEntryResponseValidator, response);
 }
 
-const saveEntryRequestInputValidator = tShape({
+const saveEntryRequestInputValidator = tShape<SaveEntryRequest>({
   entryID: tID,
   text: t.String,
   prevText: t.String,
@@ -212,15 +223,18 @@
 
 async function entryUpdateResponder(
   viewer: Viewer,
-  input: any,
+  input: mixed,
 ): Promise<SaveEntryResponse> {
-  const request: SaveEntryRequest = input;
-  await validateInput(viewer, saveEntryRequestInputValidator, request);
+  const request = await validateInput(
+    viewer,
+    saveEntryRequestInputValidator,
+    input,
+  );
   const response = await updateEntry(viewer, request);
   return validateOutput(viewer, saveEntryResponseValidator, response);
 }
 
-const deleteEntryRequestInputValidator = tShape({
+const deleteEntryRequestInputValidator = tShape<DeleteEntryRequest>({
   entryID: tID,
   prevText: t.String,
   sessionID: t.maybe(t.String),
@@ -237,15 +251,18 @@
 
 async function entryDeletionResponder(
   viewer: Viewer,
-  input: any,
+  input: mixed,
 ): Promise<DeleteEntryResponse> {
-  const request: DeleteEntryRequest = input;
-  await validateInput(viewer, deleteEntryRequestInputValidator, request);
+  const request = await validateInput(
+    viewer,
+    deleteEntryRequestInputValidator,
+    input,
+  );
   const response = await deleteEntry(viewer, request);
   return validateOutput(viewer, deleteEntryResponseValidator, response);
 }
 
-const restoreEntryRequestInputValidator = tShape({
+const restoreEntryRequestInputValidator = tShape<RestoreEntryRequest>({
   entryID: tID,
   sessionID: t.maybe(t.String),
   timestamp: t.Number,
@@ -260,10 +277,13 @@
 
 async function entryRestorationResponder(
   viewer: Viewer,
-  input: any,
+  input: mixed,
 ): Promise<RestoreEntryResponse> {
-  const request: RestoreEntryRequest = input;
-  await validateInput(viewer, restoreEntryRequestInputValidator, request);
+  const request = await validateInput(
+    viewer,
+    restoreEntryRequestInputValidator,
+    input,
+  );
   const response = await restoreEntry(viewer, request);
   return validateOutput(viewer, restoreEntryResponseValidator, response);
 }
@@ -277,10 +297,13 @@
 
 async function calendarQueryUpdateResponder(
   viewer: Viewer,
-  input: any,
+  input: mixed,
 ): Promise<DeltaEntryInfosResult> {
-  const request: CalendarQuery = input;
-  await validateInput(viewer, newEntryQueryInputValidator, input);
+  const request = await validateInput(
+    viewer,
+    newEntryQueryInputValidator,
+    input,
+  );
 
   await verifyCalendarQueryThreadIDs(request);
   if (!viewer.loggedIn) {
diff --git a/keyserver/src/responders/keys-responders.js b/keyserver/src/responders/keys-responders.js
--- a/keyserver/src/responders/keys-responders.js
+++ b/keyserver/src/responders/keys-responders.js
@@ -13,7 +13,7 @@
 import type { Viewer } from '../session/viewer.js';
 import { validateInput, validateOutput } from '../utils/validation-utils.js';
 
-const getSessionPublicKeysInputValidator = tShape({
+const getSessionPublicKeysInputValidator = tShape<GetSessionPublicKeysArgs>({
   session: t.String,
 });
 
@@ -23,13 +23,16 @@
 
 async function getSessionPublicKeysResponder(
   viewer: Viewer,
-  input: any,
+  input: mixed,
 ): Promise<GetSessionPublicKeysResponse> {
   if (!viewer.loggedIn) {
     return null;
   }
-  const request: GetSessionPublicKeysArgs = input;
-  await validateInput(viewer, getSessionPublicKeysInputValidator, request);
+  const request = await validateInput(
+    viewer,
+    getSessionPublicKeysInputValidator,
+    input,
+  );
   const response = await fetchSessionPublicKeys(request.session);
   return validateOutput(
     viewer,
diff --git a/keyserver/src/responders/message-report-responder.js b/keyserver/src/responders/message-report-responder.js
--- a/keyserver/src/responders/message-report-responder.js
+++ b/keyserver/src/responders/message-report-responder.js
@@ -13,23 +13,23 @@
 import type { Viewer } from '../session/viewer.js';
 import { validateInput, validateOutput } from '../utils/validation-utils.js';
 
-const messageReportCreationRequestInputValidator = tShape({
-  messageID: tID,
-});
+const messageReportCreationRequestInputValidator =
+  tShape<MessageReportCreationRequest>({
+    messageID: tID,
+  });
 
 export const messageReportCreationResultValidator: TInterface<MessageReportCreationResult> =
   tShape<MessageReportCreationResult>({ messageInfo: rawMessageInfoValidator });
 
 async function messageReportCreationResponder(
   viewer: Viewer,
-  input: any,
+  input: mixed,
 ): Promise<MessageReportCreationResult> {
-  await validateInput(
+  const request = await validateInput(
     viewer,
     messageReportCreationRequestInputValidator,
     input,
   );
-  const request: MessageReportCreationRequest = input;
 
   const rawMessageInfos = await createMessageReport(viewer, request);
   const result = { messageInfo: rawMessageInfos[0] };
diff --git a/keyserver/src/responders/message-responders.js b/keyserver/src/responders/message-responders.js
--- a/keyserver/src/responders/message-responders.js
+++ b/keyserver/src/responders/message-responders.js
@@ -63,7 +63,7 @@
 } from '../updaters/upload-updaters.js';
 import { validateInput, validateOutput } from '../utils/validation-utils.js';
 
-const sendTextMessageRequestInputValidator = tShape({
+const sendTextMessageRequestInputValidator = tShape<SendTextMessageRequest>({
   threadID: tID,
   localID: t.maybe(t.String),
   text: t.String,
@@ -75,10 +75,13 @@
 
 async function textMessageCreationResponder(
   viewer: Viewer,
-  input: any,
+  input: mixed,
 ): Promise<SendMessageResponse> {
-  const request: SendTextMessageRequest = input;
-  await validateInput(viewer, sendTextMessageRequestInputValidator, request);
+  const request = await validateInput(
+    viewer,
+    sendTextMessageRequestInputValidator,
+    input,
+  );
 
   const { threadID, localID, text: rawText, sidebarCreation } = request;
   const text = trimMessage(rawText);
@@ -123,10 +126,12 @@
   return validateOutput(viewer, sendMessageResponseValidator, response);
 }
 
-const fetchMessageInfosRequestInputValidator = tShape({
-  cursors: t.dict(tID, t.maybe(tID)),
-  numberPerThread: t.maybe(t.Number),
-});
+const fetchMessageInfosRequestInputValidator = tShape<FetchMessageInfosRequest>(
+  {
+    cursors: t.dict(tID, t.maybe(tID)),
+    numberPerThread: t.maybe(t.Number),
+  },
+);
 
 export const fetchMessageInfosResponseValidator: TInterface<FetchMessageInfosResponse> =
   tShape<FetchMessageInfosResponse>({
@@ -137,10 +142,13 @@
 
 async function messageFetchResponder(
   viewer: Viewer,
-  input: any,
+  input: mixed,
 ): Promise<FetchMessageInfosResponse> {
-  const request: FetchMessageInfosRequest = input;
-  await validateInput(viewer, fetchMessageInfosRequestInputValidator, request);
+  const request = await validateInput(
+    viewer,
+    fetchMessageInfosRequestInputValidator,
+    input,
+  );
   const response = await fetchMessageInfos(
     viewer,
     { threadCursors: request.cursors },
@@ -152,30 +160,30 @@
   });
 }
 
-const sendMultimediaMessageRequestInputValidator = t.union([
-  // This option is only used for messageTypes.IMAGES
-  tShape({
-    threadID: tID,
-    localID: t.String,
-    sidebarCreation: t.maybe(t.Boolean),
-    mediaIDs: t.list(tID),
-  }),
-  tShape({
-    threadID: tID,
-    localID: t.String,
-    sidebarCreation: t.maybe(t.Boolean),
-    mediaMessageContents: t.list(tMediaMessageMedia),
-  }),
-]);
+const sendMultimediaMessageRequestInputValidator =
+  t.union<SendMultimediaMessageRequest>([
+    // This option is only used for messageTypes.IMAGES
+    tShape({
+      threadID: tID,
+      localID: t.String,
+      sidebarCreation: t.maybe(t.Boolean),
+      mediaIDs: t.list(tID),
+    }),
+    tShape({
+      threadID: tID,
+      localID: t.String,
+      sidebarCreation: t.maybe(t.Boolean),
+      mediaMessageContents: t.list(tMediaMessageMedia),
+    }),
+  ]);
 async function multimediaMessageCreationResponder(
   viewer: Viewer,
-  input: any,
+  input: mixed,
 ): Promise<SendMessageResponse> {
-  const request: SendMultimediaMessageRequest = input;
-  await validateInput(
+  const request = await validateInput(
     viewer,
     sendMultimediaMessageRequestInputValidator,
-    request,
+    input,
   );
 
   if (
@@ -248,19 +256,23 @@
   return validateOutput(viewer, sendMessageResponseValidator, response);
 }
 
-const sendReactionMessageRequestInputValidator = tShape({
-  threadID: tID,
-  localID: t.maybe(t.String),
-  targetMessageID: tID,
-  reaction: tRegex(onlyOneEmojiRegex),
-  action: t.enums.of(['add_reaction', 'remove_reaction']),
-});
+const sendReactionMessageRequestInputValidator =
+  tShape<SendReactionMessageRequest>({
+    threadID: tID,
+    localID: t.maybe(t.String),
+    targetMessageID: tID,
+    reaction: tRegex(onlyOneEmojiRegex),
+    action: t.enums.of(['add_reaction', 'remove_reaction']),
+  });
 async function reactionMessageCreationResponder(
   viewer: Viewer,
-  input: any,
+  input: mixed,
 ): Promise<SendMessageResponse> {
-  const request: SendReactionMessageRequest = input;
-  await validateInput(viewer, sendReactionMessageRequestInputValidator, input);
+  const request = await validateInput(
+    viewer,
+    sendReactionMessageRequestInputValidator,
+    input,
+  );
 
   const { threadID, localID, targetMessageID, reaction, action } = request;
 
@@ -323,7 +335,7 @@
   return validateOutput(viewer, sendMessageResponseValidator, response);
 }
 
-const editMessageRequestInputValidator = tShape({
+const editMessageRequestInputValidator = tShape<SendEditMessageRequest>({
   targetMessageID: tID,
   text: t.String,
 });
@@ -335,10 +347,13 @@
 
 async function editMessageCreationResponder(
   viewer: Viewer,
-  input: any,
+  input: mixed,
 ): Promise<SendEditMessageResponse> {
-  const request: SendEditMessageRequest = input;
-  await validateInput(viewer, editMessageRequestInputValidator, input);
+  const request = await validateInput(
+    viewer,
+    editMessageRequestInputValidator,
+    input,
+  );
 
   const { targetMessageID, text: rawText } = request;
   const text = trimMessage(rawText);
@@ -414,9 +429,10 @@
   return validateOutput(viewer, sendEditMessageResponseValidator, response);
 }
 
-const fetchPinnedMessagesResponderInputValidator = tShape({
-  threadID: tID,
-});
+const fetchPinnedMessagesResponderInputValidator =
+  tShape<FetchPinnedMessagesRequest>({
+    threadID: tID,
+  });
 
 export const fetchPinnedMessagesResultValidator: TInterface<FetchPinnedMessagesResult> =
   tShape<FetchPinnedMessagesResult>({
@@ -425,10 +441,9 @@
 
 async function fetchPinnedMessagesResponder(
   viewer: Viewer,
-  input: any,
+  input: mixed,
 ): Promise<FetchPinnedMessagesResult> {
-  const request: FetchPinnedMessagesRequest = input;
-  await validateInput(
+  const request = await validateInput(
     viewer,
     fetchPinnedMessagesResponderInputValidator,
     input,
diff --git a/keyserver/src/responders/relationship-responders.js b/keyserver/src/responders/relationship-responders.js
--- a/keyserver/src/responders/relationship-responders.js
+++ b/keyserver/src/responders/relationship-responders.js
@@ -13,7 +13,7 @@
 import { updateRelationships } from '../updaters/relationship-updaters.js';
 import { validateInput, validateOutput } from '../utils/validation-utils.js';
 
-const updateRelationshipInputValidator = tShape({
+const updateRelationshipInputValidator = tShape<RelationshipRequest>({
   action: t.enums.of(relationshipActionsList, 'relationship action'),
   userIDs: t.list(t.String),
 });
@@ -27,10 +27,13 @@
 
 async function updateRelationshipsResponder(
   viewer: Viewer,
-  input: any,
+  input: mixed,
 ): Promise<RelationshipErrors> {
-  const request: RelationshipRequest = input;
-  await validateInput(viewer, updateRelationshipInputValidator, request);
+  const request = await validateInput(
+    viewer,
+    updateRelationshipInputValidator,
+    input,
+  );
   const response = await updateRelationships(viewer, request);
   return validateOutput(viewer, relationshipErrorsValidator, response);
 }
diff --git a/keyserver/src/responders/report-responders.js b/keyserver/src/responders/report-responders.js
--- a/keyserver/src/responders/report-responders.js
+++ b/keyserver/src/responders/report-responders.js
@@ -107,7 +107,7 @@
   ),
 });
 
-const reportCreationRequestInputValidator = t.union([
+const reportCreationRequestInputValidator = t.union<ReportCreationRequest>([
   tShape({
     type: t.maybe(
       t.irreducible('reportTypes.ERROR', x => x === reportTypes.ERROR),
@@ -138,20 +138,23 @@
 
 async function reportCreationResponder(
   viewer: Viewer,
-  input: any,
+  input: mixed,
 ): Promise<ReportCreationResponse> {
-  await validateInput(viewer, reportCreationRequestInputValidator, input);
-  if (input.type === null || input.type === undefined) {
-    input.type = reportTypes.ERROR;
+  let request = await validateInput(
+    viewer,
+    reportCreationRequestInputValidator,
+    input,
+  );
+  if (request.type === null || request.type === undefined) {
+    request.type = reportTypes.ERROR;
   }
-  if (!input.platformDetails && input.deviceType) {
-    const { deviceType, codeVersion, stateVersion, ...rest } = input;
-    input = {
+  if (!request.platformDetails && request.deviceType) {
+    const { deviceType, codeVersion, stateVersion, ...rest } = request;
+    request = {
       ...rest,
       platformDetails: { platform: deviceType, codeVersion, stateVersion },
     };
   }
-  const request: ReportCreationRequest = input;
   const response = await createReport(viewer, request);
   if (!response) {
     throw new ServerError('ignored_report');
@@ -159,43 +162,46 @@
   return validateOutput(viewer, reportCreationResponseValidator, response);
 }
 
-const reportMultiCreationRequestInputValidator = tShape({
-  reports: t.list(
-    t.union([
-      tShape({
-        type: t.irreducible('reportTypes.ERROR', x => x === reportTypes.ERROR),
-        platformDetails: tPlatformDetails,
-        errors: t.list(
-          tShape({
-            errorMessage: t.String,
-            stack: t.maybe(t.String),
-            componentStack: t.maybe(t.String),
-          }),
-        ),
-        preloadedState: t.Object,
-        currentState: t.Object,
-        actions: t.list(t.union([t.Object, t.String])),
-      }),
-      threadInconsistencyReportCreationRequest,
-      entryInconsistencyReportCreationRquest,
-      mediaMissionReportCreationRequest,
-      userInconsistencyReportCreationRequest,
-    ]),
-  ),
-});
+const reportMultiCreationRequestInputValidator =
+  tShape<ReportMultiCreationRequest>({
+    reports: t.list(
+      t.union([
+        tShape({
+          type: t.irreducible(
+            'reportTypes.ERROR',
+            x => x === reportTypes.ERROR,
+          ),
+          platformDetails: tPlatformDetails,
+          errors: t.list(
+            tShape({
+              errorMessage: t.String,
+              stack: t.maybe(t.String),
+              componentStack: t.maybe(t.String),
+            }),
+          ),
+          preloadedState: t.Object,
+          currentState: t.Object,
+          actions: t.list(t.union([t.Object, t.String])),
+        }),
+        threadInconsistencyReportCreationRequest,
+        entryInconsistencyReportCreationRquest,
+        mediaMissionReportCreationRequest,
+        userInconsistencyReportCreationRequest,
+      ]),
+    ),
+  });
 
 type ReportMultiCreationRequest = {
   reports: $ReadOnlyArray<ReportCreationRequest>,
 };
 async function reportMultiCreationResponder(
   viewer: Viewer,
-  input: any,
+  input: mixed,
 ): Promise<void> {
-  const request: ReportMultiCreationRequest = input;
-  await validateInput(
+  const request = await validateInput(
     viewer,
     reportMultiCreationRequestInputValidator,
-    request,
+    input,
   );
   await Promise.all(
     request.reports.map(reportCreationRequest =>
@@ -204,9 +210,10 @@
   );
 }
 
-const fetchErrorReportInfosRequestInputValidator = tShape({
-  cursor: t.maybe(t.String),
-});
+const fetchErrorReportInfosRequestInputValidator =
+  tShape<FetchErrorReportInfosRequest>({
+    cursor: t.maybe(t.String),
+  });
 
 export const fetchErrorReportInfosResponseValidator: TInterface<FetchErrorReportInfosResponse> =
   tShape<FetchErrorReportInfosResponse>({
@@ -216,13 +223,12 @@
 
 async function errorReportFetchInfosResponder(
   viewer: Viewer,
-  input: any,
+  input: mixed,
 ): Promise<FetchErrorReportInfosResponse> {
-  const request: FetchErrorReportInfosRequest = input;
-  await validateInput(
+  const request = await validateInput(
     viewer,
     fetchErrorReportInfosRequestInputValidator,
-    request,
+    input,
   );
   const response = await fetchErrorReportInfos(viewer, request);
   return validateOutput(
diff --git a/keyserver/src/responders/search-responders.js b/keyserver/src/responders/search-responders.js
--- a/keyserver/src/responders/search-responders.js
+++ b/keyserver/src/responders/search-responders.js
@@ -13,7 +13,7 @@
 import type { Viewer } from '../session/viewer.js';
 import { validateInput, validateOutput } from '../utils/validation-utils.js';
 
-const userSearchRequestInputValidator = tShape({
+const userSearchRequestInputValidator = tShape<UserSearchRequest>({
   prefix: t.maybe(t.String),
 });
 
@@ -24,10 +24,13 @@
 
 async function userSearchResponder(
   viewer: Viewer,
-  input: any,
+  input: mixed,
 ): Promise<UserSearchResult> {
-  const request: UserSearchRequest = input;
-  await validateInput(viewer, userSearchRequestInputValidator, request);
+  const request = await validateInput(
+    viewer,
+    userSearchRequestInputValidator,
+    input,
+  );
   const searchResults = await searchForUsers(request);
   const result = { userInfos: searchResults };
   return validateOutput(viewer, userSearchResultValidator, result);
diff --git a/keyserver/src/responders/thread-responders.js b/keyserver/src/responders/thread-responders.js
--- a/keyserver/src/responders/thread-responders.js
+++ b/keyserver/src/responders/thread-responders.js
@@ -58,7 +58,7 @@
 } from '../updaters/thread-updaters.js';
 import { validateInput, validateOutput } from '../utils/validation-utils.js';
 
-const threadDeletionRequestInputValidator = tShape({
+const threadDeletionRequestInputValidator = tShape<ThreadDeletionRequest>({
   threadID: tID,
   accountPassword: t.maybe(tPassword),
 });
@@ -73,10 +73,13 @@
 
 async function threadDeletionResponder(
   viewer: Viewer,
-  input: any,
+  input: mixed,
 ): Promise<LeaveThreadResult> {
-  const request: ThreadDeletionRequest = input;
-  await validateInput(viewer, threadDeletionRequestInputValidator, request);
+  const request = await validateInput(
+    viewer,
+    threadDeletionRequestInputValidator,
+    input,
+  );
   const result = await deleteThread(viewer, request);
   return validateOutput(viewer, leaveThreadResultValidator, result);
 }
@@ -106,44 +109,53 @@
 
 async function roleUpdateResponder(
   viewer: Viewer,
-  input: any,
+  input: mixed,
 ): Promise<ChangeThreadSettingsResult> {
-  const request: RoleChangeRequest = input;
-  await validateInput(viewer, roleChangeRequestInputValidator, request);
+  const request = await validateInput(
+    viewer,
+    roleChangeRequestInputValidator,
+    input,
+  );
   const result = await updateRole(viewer, request);
   return validateOutput(viewer, changeThreadSettingsResultValidator, result);
 }
 
-const removeMembersRequestInputValidator = tShape({
+const removeMembersRequestInputValidator = tShape<RemoveMembersRequest>({
   threadID: tID,
   memberIDs: t.list(t.String),
 });
 
 async function memberRemovalResponder(
   viewer: Viewer,
-  input: any,
+  input: mixed,
 ): Promise<ChangeThreadSettingsResult> {
-  const request: RemoveMembersRequest = input;
-  await validateInput(viewer, removeMembersRequestInputValidator, request);
+  const request = await validateInput(
+    viewer,
+    removeMembersRequestInputValidator,
+    input,
+  );
   const result = await removeMembers(viewer, request);
   return validateOutput(viewer, changeThreadSettingsResultValidator, result);
 }
 
-const leaveThreadRequestInputValidator = tShape({
+const leaveThreadRequestInputValidator = tShape<LeaveThreadRequest>({
   threadID: tID,
 });
 
 async function threadLeaveResponder(
   viewer: Viewer,
-  input: any,
+  input: mixed,
 ): Promise<LeaveThreadResult> {
-  const request: LeaveThreadRequest = input;
-  await validateInput(viewer, leaveThreadRequestInputValidator, request);
+  const request = await validateInput(
+    viewer,
+    leaveThreadRequestInputValidator,
+    input,
+  );
   const result = await leaveThread(viewer, request);
   return validateOutput(viewer, leaveThreadResultValidator, result);
 }
 
-const updateThreadRequestInputValidator = tShape({
+const updateThreadRequestInputValidator = tShape<UpdateThreadRequest>({
   threadID: tID,
   changes: tShape({
     type: t.maybe(tNumEnum(values(threadTypes))),
@@ -159,10 +171,13 @@
 
 async function threadUpdateResponder(
   viewer: Viewer,
-  input: any,
+  input: mixed,
 ): Promise<ChangeThreadSettingsResult> {
-  const request: UpdateThreadRequest = input;
-  await validateInput(viewer, updateThreadRequestInputValidator, request);
+  const request = await validateInput(
+    viewer,
+    updateThreadRequestInputValidator,
+    input,
+  );
   const result = await updateThread(viewer, request);
   return validateOutput(viewer, changeThreadSettingsResultValidator, result);
 }
@@ -205,10 +220,13 @@
 
 async function threadCreationResponder(
   viewer: Viewer,
-  input: any,
+  input: mixed,
 ): Promise<NewThreadResponse> {
-  const request: ServerNewThreadRequest = input;
-  await validateInput(viewer, newThreadRequestInputValidator, request);
+  const request = await validateInput(
+    viewer,
+    newThreadRequestInputValidator,
+    input,
+  );
 
   const result = await createThread(viewer, request, {
     silentlyFailMembers: request.type === threadTypes.SIDEBAR,
@@ -216,7 +234,7 @@
   return validateOutput(viewer, newThreadResponseValidator, result);
 }
 
-const joinThreadRequestInputValidator = tShape({
+const joinThreadRequestInputValidator = tShape<ServerThreadJoinRequest>({
   threadID: tID,
   calendarQuery: t.maybe(entryQueryInputValidator),
   inviteLinkSecret: t.maybe(t.String),
@@ -236,10 +254,13 @@
 
 async function threadJoinResponder(
   viewer: Viewer,
-  input: any,
+  input: mixed,
 ): Promise<ThreadJoinResult> {
-  const request: ServerThreadJoinRequest = input;
-  await validateInput(viewer, joinThreadRequestInputValidator, request);
+  const request = await validateInput(
+    viewer,
+    joinThreadRequestInputValidator,
+    input,
+  );
 
   if (request.calendarQuery) {
     await verifyCalendarQueryThreadIDs(request.calendarQuery);
@@ -249,7 +270,7 @@
   return validateOutput(viewer, threadJoinResultValidator, result);
 }
 
-const threadFetchMediaRequestInputValidator = tShape({
+const threadFetchMediaRequestInputValidator = tShape<ThreadFetchMediaRequest>({
   threadID: tID,
   limit: t.Number,
   offset: t.Number,
@@ -260,15 +281,18 @@
 
 async function threadFetchMediaResponder(
   viewer: Viewer,
-  input: any,
+  input: mixed,
 ): Promise<ThreadFetchMediaResult> {
-  const request: ThreadFetchMediaRequest = input;
-  await validateInput(viewer, threadFetchMediaRequestInputValidator, request);
+  const request = await validateInput(
+    viewer,
+    threadFetchMediaRequestInputValidator,
+    input,
+  );
   const result = await fetchMediaForThread(viewer, request);
   return validateOutput(viewer, threadFetchMediaResultValidator, result);
 }
 
-const toggleMessagePinRequestInputValidator = tShape({
+const toggleMessagePinRequestInputValidator = tShape<ToggleMessagePinRequest>({
   messageID: tID,
   action: t.enums.of(['pin', 'unpin']),
 });
@@ -281,10 +305,13 @@
 
 async function toggleMessagePinResponder(
   viewer: Viewer,
-  input: any,
+  input: mixed,
 ): Promise<ToggleMessagePinResult> {
-  const request: ToggleMessagePinRequest = input;
-  await validateInput(viewer, toggleMessagePinRequestInputValidator, request);
+  const request = await validateInput(
+    viewer,
+    toggleMessagePinRequestInputValidator,
+    input,
+  );
   const result = await toggleMessagePinForThread(viewer, request);
   return validateOutput(viewer, toggleMessagePinResultValidator, result);
 }
diff --git a/keyserver/src/responders/user-responders.js b/keyserver/src/responders/user-responders.js
--- a/keyserver/src/responders/user-responders.js
+++ b/keyserver/src/responders/user-responders.js
@@ -32,7 +32,6 @@
 import {
   type ClientAvatar,
   clientAvatarValidator,
-  type UpdateUserAvatarRequest,
   type UpdateUserAvatarResponse,
 } from 'lib/types/avatar-types.js';
 import type {
@@ -119,6 +118,7 @@
   createNewUserCookie,
   setNewSession,
 } from '../session/cookies.js';
+import { verifyClientSupported } from '../session/version.js';
 import type { Viewer } from '../session/viewer.js';
 import {
   accountUpdater,
@@ -133,13 +133,14 @@
 import { getOlmUtility } from '../utils/olm-utils.js';
 import { validateInput, validateOutput } from '../utils/validation-utils.js';
 
-const subscriptionUpdateRequestInputValidator = tShape({
-  threadID: tID,
-  updatedFields: tShape({
-    pushNotifs: t.maybe(t.Boolean),
-    home: t.maybe(t.Boolean),
-  }),
-});
+const subscriptionUpdateRequestInputValidator =
+  tShape<SubscriptionUpdateRequest>({
+    threadID: tID,
+    updatedFields: tShape({
+      pushNotifs: t.maybe(t.Boolean),
+      home: t.maybe(t.Boolean),
+    }),
+  });
 
 export const subscriptionUpdateResponseValidator: TInterface<SubscriptionUpdateResponse> =
   tShape<SubscriptionUpdateResponse>({
@@ -148,17 +149,20 @@
 
 async function userSubscriptionUpdateResponder(
   viewer: Viewer,
-  input: any,
+  input: mixed,
 ): Promise<SubscriptionUpdateResponse> {
-  const request: SubscriptionUpdateRequest = input;
-  await validateInput(viewer, subscriptionUpdateRequestInputValidator, request);
+  const request = await validateInput(
+    viewer,
+    subscriptionUpdateRequestInputValidator,
+    input,
+  );
   const threadSubscription = await userSubscriptionUpdater(viewer, request);
   return validateOutput(viewer, subscriptionUpdateResponseValidator, {
     threadSubscription,
   });
 }
 
-const accountUpdateInputValidator = tShape({
+const accountUpdateInputValidator = tShape<PasswordUpdate>({
   updatedFields: tShape({
     email: t.maybe(tEmail),
     password: t.maybe(tPassword),
@@ -168,28 +172,36 @@
 
 async function passwordUpdateResponder(
   viewer: Viewer,
-  input: any,
+  input: mixed,
 ): Promise<void> {
-  const request: PasswordUpdate = input;
-  await validateInput(viewer, accountUpdateInputValidator, request);
+  const request = await validateInput(
+    viewer,
+    accountUpdateInputValidator,
+    input,
+  );
   await accountUpdater(viewer, request);
 }
 
 async function sendVerificationEmailResponder(viewer: Viewer): Promise<void> {
-  await validateInput(viewer, null, null);
+  if (!viewer.isSocket) {
+    await verifyClientSupported(viewer, viewer.platformDetails);
+  }
   await checkAndSendVerificationEmail(viewer);
 }
 
-const resetPasswordRequestInputValidator = tShape({
+const resetPasswordRequestInputValidator = tShape<ResetPasswordRequest>({
   usernameOrEmail: t.union([tEmail, tOldValidUsername]),
 });
 
 async function sendPasswordResetEmailResponder(
   viewer: Viewer,
-  input: any,
+  input: mixed,
 ): Promise<void> {
-  const request: ResetPasswordRequest = input;
-  await validateInput(viewer, resetPasswordRequestInputValidator, request);
+  const request = await validateInput(
+    viewer,
+    resetPasswordRequestInputValidator,
+    input,
+  );
   await checkAndSendPasswordResetEmail(request);
 }
 
@@ -199,7 +211,9 @@
   });
 
 async function logOutResponder(viewer: Viewer): Promise<LogOutResponse> {
-  await validateInput(viewer, null, null);
+  if (!viewer.isSocket) {
+    await verifyClientSupported(viewer, viewer.platformDetails);
+  }
   if (viewer.loggedIn) {
     const [anonymousViewerData] = await Promise.all([
       createNewAnonymousCookie({
@@ -219,16 +233,19 @@
   return validateOutput(viewer, logOutResponseValidator, response);
 }
 
-const deleteAccountRequestInputValidator = tShape({
+const deleteAccountRequestInputValidator = tShape<DeleteAccountRequest>({
   password: t.maybe(tPassword),
 });
 
 async function accountDeletionResponder(
   viewer: Viewer,
-  input: any,
+  input: mixed,
 ): Promise<LogOutResponse> {
-  const request: DeleteAccountRequest = input;
-  await validateInput(viewer, deleteAccountRequestInputValidator, request);
+  const request = await validateInput(
+    viewer,
+    deleteAccountRequestInputValidator,
+    input,
+  );
   const result = await deleteAccount(viewer, request);
   invariant(result, 'deleteAccount should return result if handed request');
   return validateOutput(viewer, logOutResponseValidator, result);
@@ -239,7 +256,7 @@
   deviceToken: t.String,
 });
 
-const registerRequestInputValidator = tShape({
+const registerRequestInputValidator = tShape<RegisterRequest>({
   username: t.String,
   email: t.maybe(tEmail),
   password: tPassword,
@@ -268,10 +285,13 @@
 
 async function accountCreationResponder(
   viewer: Viewer,
-  input: any,
+  input: mixed,
 ): Promise<RegisterResponse> {
-  const request: RegisterRequest = input;
-  await validateInput(viewer, registerRequestInputValidator, request);
+  const request = await validateInput(
+    viewer,
+    registerRequestInputValidator,
+    input,
+  );
   const { signedIdentityKeysBlob } = request;
   if (signedIdentityKeysBlob) {
     const identityKeys: IdentityKeysBlob = JSON.parse(
@@ -399,7 +419,7 @@
   return response;
 }
 
-const logInRequestInputValidator = tShape({
+const logInRequestInputValidator = tShape<LogInRequest>({
   username: t.maybe(t.String),
   usernameOrEmail: t.maybe(t.union([tEmail, tOldValidUsername])),
   password: tPassword,
@@ -434,10 +454,13 @@
 
 async function logInResponder(
   viewer: Viewer,
-  input: any,
+  input: mixed,
 ): Promise<LogInResponse> {
-  await validateInput(viewer, logInRequestInputValidator, input);
-  const request: LogInRequest = input;
+  const request = await validateInput(
+    viewer,
+    logInRequestInputValidator,
+    input,
+  );
 
   let identityKeys: ?IdentityKeysBlob;
   const { signedIdentityKeysBlob } = request;
@@ -508,7 +531,7 @@
   return validateOutput(viewer, logInResponseValidator, response);
 }
 
-const siweAuthRequestInputValidator = tShape({
+const siweAuthRequestInputValidator = tShape<SIWEAuthRequest>({
   signature: t.String,
   message: t.String,
   calendarQuery: entryQueryInputValidator,
@@ -520,10 +543,14 @@
 
 async function siweAuthResponder(
   viewer: Viewer,
-  input: any,
+  input: mixed,
 ): Promise<LogInResponse> {
-  await validateInput(viewer, siweAuthRequestInputValidator, input);
-  const request: SIWEAuthRequest = input;
+  const request = await validateInput(
+    viewer,
+    siweAuthRequestInputValidator,
+    input,
+  );
+
   const {
     message,
     signature,
@@ -644,7 +671,7 @@
   return validateOutput(viewer, logInResponseValidator, response);
 }
 
-const updatePasswordRequestInputValidator = tShape({
+const updatePasswordRequestInputValidator = tShape<UpdatePasswordRequest>({
   code: t.String,
   password: tPassword,
   watchedIDs: t.list(tID),
@@ -655,10 +682,14 @@
 
 async function oldPasswordUpdateResponder(
   viewer: Viewer,
-  input: any,
+  input: mixed,
 ): Promise<LogInResponse> {
-  await validateInput(viewer, updatePasswordRequestInputValidator, input);
-  const request: UpdatePasswordRequest = input;
+  const request = await validateInput(
+    viewer,
+    updatePasswordRequestInputValidator,
+    input,
+  );
+
   if (request.calendarQuery) {
     request.calendarQuery = normalizeCalendarQuery(request.calendarQuery);
   }
@@ -666,7 +697,7 @@
   return validateOutput(viewer, logInResponseValidator, response);
 }
 
-const updateUserSettingsInputValidator = tShape({
+const updateUserSettingsInputValidator = tShape<UpdateUserSettingsRequest>({
   name: t.irreducible(
     userSettingsTypes.DEFAULT_NOTIFICATIONS,
     x => x === userSettingsTypes.DEFAULT_NOTIFICATIONS,
@@ -676,26 +707,29 @@
 
 async function updateUserSettingsResponder(
   viewer: Viewer,
-  input: any,
+  input: mixed,
 ): Promise<void> {
-  const request: UpdateUserSettingsRequest = input;
-  await validateInput(viewer, updateUserSettingsInputValidator, request);
+  const request = await validateInput(
+    viewer,
+    updateUserSettingsInputValidator,
+    input,
+  );
   await updateUserSettings(viewer, request);
 }
 
-const policyAcknowledgmentRequestInputValidator = tShape({
-  policy: t.maybe(t.enums.of(policies)),
-});
+const policyAcknowledgmentRequestInputValidator =
+  tShape<PolicyAcknowledgmentRequest>({
+    policy: t.maybe(t.enums.of(policies)),
+  });
 
 async function policyAcknowledgmentResponder(
   viewer: Viewer,
-  input: any,
+  input: mixed,
 ): Promise<void> {
-  const request: PolicyAcknowledgmentRequest = input;
-  await validateInput(
+  const request = await validateInput(
     viewer,
     policyAcknowledgmentRequestInputValidator,
-    request,
+    input,
   );
   await viewerAcknowledgmentUpdater(viewer, request.policy);
 }
@@ -712,10 +746,13 @@
 
 async function updateUserAvatarResponder(
   viewer: Viewer,
-  input: any,
+  input: mixed,
 ): Promise<?ClientAvatar | UpdateUserAvatarResponse> {
-  const request: UpdateUserAvatarRequest = input;
-  await validateInput(viewer, updateUserAvatarRequestValidator, request);
+  const request = await validateInput(
+    viewer,
+    updateUserAvatarRequestValidator,
+    input,
+  );
   const result = await updateUserAvatar(viewer, request);
   return validateOutput(viewer, updateUserAvatarResponderValidator, result);
 }
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
@@ -21,19 +21,33 @@
 import { verifyClientSupported } from '../session/version.js';
 import type { Viewer } from '../session/viewer.js';
 
+const convertToNewIDSchema = false;
+const keyserverPrefixID = '256';
+
 async function validateInput<T>(
   viewer: Viewer,
-  inputValidator: ?TType<T>,
-  input: T,
-) {
+  inputValidator: TType<T>,
+  input: mixed,
+): Promise<T> {
   if (!viewer.isSocket) {
     await checkClientSupported(viewer, inputValidator, input);
   }
-  checkInputValidator(inputValidator, input);
-}
+  const convertedInput = checkInputValidator(inputValidator, input);
 
-const convertToNewIDSchema = false;
-const keyserverPrefixID = '256';
+  if (
+    hasMinCodeVersion(viewer.platformDetails, 1000) &&
+    !isWebPlatform(viewer.platformDetails?.platform) &&
+    convertToNewIDSchema
+  ) {
+    return convertClientIDsToServerIDs(
+      keyserverPrefixID,
+      inputValidator,
+      convertedInput,
+    );
+  }
+
+  return convertedInput;
+}
 
 function validateOutput<T>(
   viewer: Viewer,
@@ -96,9 +110,9 @@
   return convertObject(outputValidator, data, [tID], conversionFunction);
 }
 
-function checkInputValidator<T>(inputValidator: ?TType<T>, input: T) {
-  if (!inputValidator || inputValidator.is(input)) {
-    return;
+function checkInputValidator<T>(inputValidator: TType<T>, input: mixed): T {
+  if (inputValidator.is(input)) {
+    return assertWithValidator(input, inputValidator);
   }
   const error = new ServerError('invalid_parameters');
   error.sanitizedInput = input ? sanitizeInput(inputValidator, input) : null;
diff --git a/lib/types/account-types.js b/lib/types/account-types.js
--- a/lib/types/account-types.js
+++ b/lib/types/account-types.js
@@ -51,10 +51,12 @@
 
 export type RegisterRequest = {
   +username: string,
+  +email?: empty,
   +password: string,
   +calendarQuery?: ?CalendarQuery,
   +deviceTokenUpdateRequest?: ?DeviceTokenUpdateRequest,
   +platformDetails: PlatformDetails,
+  +primaryIdentityPublicKey?: empty,
   +signedIdentityKeysBlob?: SignedIdentityKeysBlob,
 };
 
@@ -125,6 +127,7 @@
   +platformDetails: PlatformDetails,
   +watchedIDs: $ReadOnlyArray<string>,
   +source?: LogInActionSource,
+  +primaryIdentityPublicKey?: empty,
   +signedIdentityKeysBlob?: SignedIdentityKeysBlob,
 };
 
diff --git a/lib/types/entry-types.js b/lib/types/entry-types.js
--- a/lib/types/entry-types.js
+++ b/lib/types/entry-types.js
@@ -96,6 +96,7 @@
 
 export type SaveEntryRequest = {
   +entryID: string,
+  +sessionID?: empty,
   +text: string,
   +prevText: string,
   +timestamp: number,
@@ -130,6 +131,7 @@
 
 export type CreateEntryRequest = {
   +text: string,
+  +sessionID?: empty,
   +timestamp: number,
   +date: string,
   +threadID: string,
@@ -150,6 +152,7 @@
 
 export type DeleteEntryRequest = {
   +entryID: string,
+  +sessionID?: empty,
   +prevText: string,
   +timestamp: number,
   +calendarQuery?: CalendarQuery,
@@ -162,6 +165,7 @@
 
 export type RestoreEntryRequest = {
   +entryID: string,
+  +sessionID?: empty,
   +timestamp: number,
   +calendarQuery?: CalendarQuery,
 };
diff --git a/lib/types/thread-types.js b/lib/types/thread-types.js
--- a/lib/types/thread-types.js
+++ b/lib/types/thread-types.js
@@ -459,6 +459,7 @@
 export type UpdateThreadRequest = {
   +threadID: string,
   +changes: ThreadChanges,
+  +accountPassword?: empty,
 };
 
 export type BaseNewThreadRequest = {