diff --git a/client/src/api/queries.ts b/client/src/api/queries.ts
index ebe24cc..be3bfd4 100644
--- a/client/src/api/queries.ts
+++ b/client/src/api/queries.ts
@@ -7,6 +7,10 @@ import type {
   Webhook,
   PaginatedResponse,
 } from '../../../shared/types';
+import type { CreateTicketInput, UpdateTicketInput } from '../../../shared/schemas/ticket';
+import type { CreateUserInput, UpdateUserInput } from '../../../shared/schemas/user';
+import type { UpdateWebhookInput } from '../../../shared/schemas/notification';
+import type { CreateSavedViewInput } from '../../../shared/schemas/savedView';
 
 // ── Keys ─────────────────────────────────────────────────────────────────────
 
@@ -96,7 +100,7 @@ export function useTicketAudit(id: string | undefined, enabled = true) {
 export function useCreateTicket() {
   const qc = useQueryClient();
   return useMutation({
-    mutationFn: async (data: Record<string, unknown>) =>
+    mutationFn: async (data: CreateTicketInput) =>
       (await api.post<Ticket>('/tickets', data)).data,
     onSuccess: () => {
       qc.invalidateQueries({ queryKey: ['tickets'] });
@@ -107,7 +111,7 @@ export function useCreateTicket() {
 export function useUpdateTicket() {
   const qc = useQueryClient();
   return useMutation({
-    mutationFn: async ({ id, data }: { id: string; data: Record<string, unknown> }) =>
+    mutationFn: async ({ id, data }: { id: string; data: UpdateTicketInput }) =>
       (await api.patch<Ticket>(`/tickets/${id}`, data)).data,
     onSuccess: (ticket) => {
       qc.setQueryData(qk.ticket(ticket.displayId), ticket);
@@ -265,7 +269,7 @@ export function useUsers() {
 export function useCreateUser() {
   const qc = useQueryClient();
   return useMutation({
-    mutationFn: async (data: Record<string, unknown>) =>
+    mutationFn: async (data: CreateUserInput) =>
       (await api.post<User>('/users', data)).data,
     onSuccess: () => qc.invalidateQueries({ queryKey: qk.users() }),
   });
@@ -274,7 +278,7 @@ export function useCreateUser() {
 export function useUpdateUser() {
   const qc = useQueryClient();
   return useMutation({
-    mutationFn: async ({ id, data }: { id: string; data: Record<string, unknown> }) =>
+    mutationFn: async ({ id, data }: { id: string; data: UpdateUserInput }) =>
       (await api.patch<User>(`/users/${id}`, data)).data,
     onSuccess: () => qc.invalidateQueries({ queryKey: qk.users() }),
   });
@@ -344,7 +348,7 @@ export function useCreateWebhook() {
 export function useUpdateWebhook() {
   const qc = useQueryClient();
   return useMutation({
-    mutationFn: async ({ id, data }: { id: string; data: Record<string, unknown> }) =>
+    mutationFn: async ({ id, data }: { id: string; data: UpdateWebhookInput }) =>
       (await api.patch<Webhook>(`/webhooks/${id}`, data)).data,
     onSuccess: () => qc.invalidateQueries({ queryKey: qk.webhooks() }),
   });
@@ -382,7 +386,7 @@ export function useSavedViews() {
 export function useCreateSavedView() {
   const qc = useQueryClient();
   return useMutation({
-    mutationFn: async (data: { name: string; filters: Record<string, unknown> }) =>
+    mutationFn: async (data: CreateSavedViewInput) =>
       (await api.post<SavedView>('/saved-views', data)).data,
     onSuccess: () => qc.invalidateQueries({ queryKey: qk.savedViews() }),
   });
diff --git a/client/src/pages/NewTicket.tsx b/client/src/pages/NewTicket.tsx
index be1e9c6..5525211 100644
--- a/client/src/pages/NewTicket.tsx
+++ b/client/src/pages/NewTicket.tsx
@@ -38,9 +38,10 @@ export default function NewTicketModal({ onClose }: NewTicketModalProps) {
   const onSubmit = async (data: CreateTicketInput) => {
     setError('');
     try {
-      const payload: Record<string, unknown> = { ...data };
-      if (!data.assigneeId) delete payload.assigneeId;
-      const created = await createTicket.mutateAsync(payload);
+      const { assigneeId, ...rest } = data;
+      const created = await createTicket.mutateAsync(
+        assigneeId ? { ...rest, assigneeId } : rest,
+      );
       onClose();
       navigate(`/${created.displayId}`);
     } catch {
diff --git a/client/src/pages/Tickets.tsx b/client/src/pages/Tickets.tsx
index f85f18b..4d662d3 100644
--- a/client/src/pages/Tickets.tsx
+++ b/client/src/pages/Tickets.tsx
@@ -154,7 +154,7 @@ export default function Tickets() {
   const currentFilters = useMemo(
     () => ({
       status: status || undefined,
-      severity: severity || undefined,
+      severity: severity ? Number(severity) : undefined,
       assigneeId: assigneeId || undefined,
       categoryId: categoryId || undefined,
       typeId: typeId || undefined,
diff --git a/client/src/pages/admin/Users.tsx b/client/src/pages/admin/Users.tsx
index 54b1f9e..3bfa46e 100644
--- a/client/src/pages/admin/Users.tsx
+++ b/client/src/pages/admin/Users.tsx
@@ -4,6 +4,7 @@ import { toast } from 'sonner';
 import Layout from '../../components/Layout';
 import Modal from '../../components/Modal';
 import { User, Role } from '../../types';
+import type { CreateUserInput } from '../../../../shared/schemas/user';
 import { useAuth } from '../../contexts/AuthContext';
 import {
   useUsers,
@@ -105,14 +106,13 @@ export default function AdminUsers() {
     e.preventDefault();
     setError('');
     try {
-      const payload: Record<string, string> = {
+      const created = await createUser.mutateAsync({
         username: form.username,
         email: form.email,
         displayName: form.displayName,
-        role: form.role,
-      };
-      if (form.password) payload.password = form.password;
-      const created = await createUser.mutateAsync(payload);
+        role: form.role as CreateUserInput['role'],
+        password: form.password,
+      });
       if (created.apiKey) setNewApiKey(created.apiKey);
       else closeModal();
     } catch (err: unknown) {