diff --git a/packages/shared/src/schemas.ts b/packages/shared/src/schemas.ts
new file mode 100644
index 0000000..2912c42
--- /dev/null
+++ b/packages/shared/src/schemas.ts
@@ -0,0 +1,69 @@
+import { z } from "zod"
+
+export const UserRoleSchema = z.enum(["admin", "user"])
+
+export const UserInsertSchema = UserRoleSchema.extend({
+  email: z.string().email(),
+  name: z.string().min(1),
+  role: UserRoleSchema,
+  passwordHash: z.string().min(1)
+})
+
+export const UserSelectSchema = UserInsertSchema.extend({
+  id: z.string().uuid(),
+  createdAt: z.date()
+}).omit({ passwordHash: true })
+
+export const CustomerInsertSchema = z.object({
+  name: z.string().min(1),
+  active: z.boolean().default(true)
+})
+
+export const CustomerSelectSchema = CustomerInsertSchema.extend({
+  id: z.string().uuid(),
+  createdAt: z.date()
+})
+
+export const ProjectInsertSchema = z.object({
+  name: z.string().min(1),
+  customerId: z.string().uuid(),
+  active: z.boolean().default(true)
+})
+
+export const ProjectSelectSchema = ProjectInsertSchema.extend({
+  id: z.string().uuid(),
+  createdAt: z.date()
+})
+
+export const TimeEntryInsertSchema = z.object({
+  userId: z.string().uuid(),
+  projectId: z.string().uuid().optional(),
+  description: z.string().min(1),
+  startTime: z.date(),
+  endTime: z.date().optional()
+})
+
+export const TimeEntrySelectSchema = TimeEntryInsertSchema.extend({
+  id: z.string().uuid(),
+  createdAt: z.date()
+})
+
+export const LoginRequestSchema = z.object({
+  email: z.string().email(),
+  password: z.string().min(1)
+})
+
+export type UserInsert = z.infer<typeof UserInsertSchema>
+export type UserSelect = z.infer<typeof UserSelectSchema>
+export type UserRole = z.infer<typeof UserRoleSchema>
+
+export type CustomerInsert = z.infer<typeof CustomerInsertSchema>
+export type CustomerSelect = z.infer<typeof CustomerSelectSchema>
+
+export type ProjectInsert = z.infer<typeof ProjectInsertSchema>
+export type ProjectSelect = z.infer<typeof ProjectSelectSchema>
+
+export type TimeEntryInsert = z.infer<typeof TimeEntryInsertSchema>
+export type TimeEntrySelect = z.infer<typeof TimeEntrySelectSchema>
+
+export type LoginRequest = z.infer<typeof LoginRequestSchema>
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