diff --git a/.gitignore b/.gitignore
index 8a0dbaf..ff8a48d 100644
--- a/.gitignore
+++ b/.gitignore
@@ -15,7 +15,7 @@ dist/
 downloads/
 eggs/
 .eggs/
-lib/
+# lib/
 lib64/
 parts/
 sdist/
diff --git a/frontend/src/lib/api-client.ts b/frontend/src/lib/api-client.ts
new file mode 100644
index 0000000..cd5ce55
--- /dev/null
+++ b/frontend/src/lib/api-client.ts
@@ -0,0 +1,122 @@
+import { env } from '@/config/env'
+import { useAuthStore } from '@/stores/auth-store'
+import type { ApiError } from '@/types/crm'
+
+export type HttpMethod = 'GET' | 'POST' | 'PATCH' | 'PUT' | 'DELETE'
+
+export interface RequestOptions<TBody = unknown> {
+  path: string
+  method?: HttpMethod
+  params?: Record<string, string | number | boolean | Array<string | number | boolean> | undefined | null>
+  body?: TBody
+  headers?: HeadersInit
+  signal?: AbortSignal
+  auth?: boolean
+}
+
+export class HttpError extends Error {
+  status: number
+  payload: ApiError | null
+
+  constructor(status: number, message: string, payload: ApiError | null = null) {
+    super(message)
+    this.status = status
+    this.payload = payload
+  }
+}
+
+const API_BASE_URL = `${env.API_URL}${env.API_PREFIX}`
+
+const buildUrl = (path: string, params?: RequestOptions['params']) => {
+  const url = new URL(path.startsWith('http') ? path : `${API_BASE_URL}${path}`)
+  if (params) {
+    Object.entries(params).forEach(([key, value]) => {
+      if (value === undefined || value === null) return
+      if (Array.isArray(value)) {
+        value.forEach((entry) => {
+          if (entry === undefined || entry === null) return
+          url.searchParams.append(key, String(entry))
+        })
+      } else {
+        url.searchParams.set(key, String(value))
+      }
+    })
+  }
+  return url.toString()
+}
+
+const parseResponse = async <T>(response: Response): Promise<T> => {
+  if (response.status === 204 || response.status === 205) {
+    return undefined as T
+  }
+  const contentType = response.headers.get('content-type') || ''
+  if (contentType.includes('application/json')) {
+    return (await response.json()) as T
+  }
+  return (await response.text()) as T
+}
+
+const requestWithRefresh = async <T>(options: RequestOptions, retry = false): Promise<T> => {
+  const { tokens, activeOrganizationId, refreshSession, logout } = useAuthStore.getState()
+  const authEnabled = options.auth !== false
+  const headers = new Headers(options.headers || {})
+
+  if (authEnabled && tokens?.accessToken) {
+    headers.set('Authorization', `Bearer ${tokens.accessToken}`)
+    if (activeOrganizationId) {
+      headers.set(env.ORG_HEADER, String(activeOrganizationId))
+    }
+  }
+
+  if (options.body && !(options.body instanceof FormData)) {
+    headers.set('Content-Type', 'application/json')
+  }
+
+  headers.set('Accept', 'application/json')
+
+  const response = await fetch(buildUrl(options.path, options.params), {
+    method: options.method ?? 'GET',
+    body:
+      options.body instanceof FormData
+        ? options.body
+        : options.body
+          ? JSON.stringify(options.body)
+          : undefined,
+    headers,
+    signal: options.signal,
+  })
+
+  if (response.status === 401 && authEnabled && !retry) {
+    try {
+      await refreshSession()
+    } catch (error) {
+      logout()
+      throw error
+    }
+    return requestWithRefresh<T>(options, true)
+  }
+
+  if (!response.ok) {
+    let payload: ApiError | null = null
+    try {
+      payload = await response.clone().json()
+    } catch {
+      payload = null
+    }
+    throw new HttpError(response.status, payload?.detail ? String(payload.detail) : response.statusText, payload)
+  }
+
+  return parseResponse<T>(response)
+}
+
+export const apiClient = {
+  request: requestWithRefresh,
+  get: <T>(path: string, options: Omit<RequestOptions, 'path' | 'method'> = {}) =>
+    requestWithRefresh<T>({ path, ...options, method: 'GET' }),
+  post: <T, TBody>(path: string, body: TBody, options: Omit<RequestOptions<TBody>, 'path' | 'method' | 'body'> = {}) =>
+    requestWithRefresh<T>({ path, body, ...options, method: 'POST' }),
+  patch: <T, TBody>(path: string, body: TBody, options: Omit<RequestOptions<TBody>, 'path' | 'method' | 'body'> = {}) =>
+    requestWithRefresh<T>({ path, body, ...options, method: 'PATCH' }),
+  delete: <T>(path: string, options: Omit<RequestOptions, 'path' | 'method'> = {}) =>
+    requestWithRefresh<T>({ path, ...options, method: 'DELETE' }),
+}
diff --git a/frontend/src/lib/query-client.ts b/frontend/src/lib/query-client.ts
new file mode 100644
index 0000000..887723c
--- /dev/null
+++ b/frontend/src/lib/query-client.ts
@@ -0,0 +1,21 @@
+import { QueryClient } from '@tanstack/react-query'
+
+export const createQueryClient = () =>
+  new QueryClient({
+    defaultOptions: {
+      queries: {
+        staleTime: 1000 * 60,
+        refetchOnWindowFocus: false,
+        refetchOnReconnect: true,
+        retry: (failureCount, error: unknown) => {
+          if (error instanceof Response && error.status === 401) {
+            return false
+          }
+          return failureCount < 3
+        },
+      },
+      mutations: {
+        retry: 0,
+      },
+    },
+  })
diff --git a/frontend/src/lib/storage.ts b/frontend/src/lib/storage.ts
new file mode 100644
index 0000000..e15012f
--- /dev/null
+++ b/frontend/src/lib/storage.ts
@@ -0,0 +1,21 @@
+export const storage = {
+  get<T>(key: string, fallback: T | null = null): T | null {
+    if (typeof window === 'undefined') return fallback
+    try {
+      const raw = window.localStorage.getItem(key)
+      if (!raw) return fallback
+      return JSON.parse(raw) as T
+    } catch (error) {
+      console.error(`Failed to parse storage item ${key}`, error)
+      return fallback
+    }
+  },
+  set<T>(key: string, value: T | null): void {
+    if (typeof window === 'undefined') return
+    if (value === null) {
+      window.localStorage.removeItem(key)
+      return
+    }
+    window.localStorage.setItem(key, JSON.stringify(value))
+  },
+}
diff --git a/frontend/src/lib/token.ts b/frontend/src/lib/token.ts
new file mode 100644
index 0000000..7f77114
--- /dev/null
+++ b/frontend/src/lib/token.ts
@@ -0,0 +1,17 @@
+import { jwtDecode } from 'jwt-decode'
+
+interface TokenPayload {
+  sub?: string
+  email?: string
+  name?: string
+  [key: string]: unknown
+}
+
+export const parseToken = (token: string) => {
+  try {
+    return jwtDecode<TokenPayload>(token)
+  } catch (error) {
+    console.error('Failed to parse token', error)
+    return null
+  }
+}
diff --git a/frontend/src/lib/utils.ts b/frontend/src/lib/utils.ts
new file mode 100644
index 0000000..380e496
--- /dev/null
+++ b/frontend/src/lib/utils.ts
@@ -0,0 +1,39 @@
+import { type ClassValue, clsx } from 'clsx'
+import { twMerge } from 'tailwind-merge'
+
+export function cn(...inputs: ClassValue[]) {
+  return twMerge(clsx(inputs))
+}
+
+export const formatCurrency = (value?: string | number | null, currency = 'USD') => {
+  if (value === null || value === undefined || value === '') return '—'
+  const amount = typeof value === 'string' ? Number(value) : value
+  if (Number.isNaN(amount)) return '—'
+  return new Intl.NumberFormat(undefined, {
+    style: 'currency',
+    currency,
+    maximumFractionDigits: 2,
+  }).format(amount)
+}
+
+export const formatDate = (value?: string | Date | null, options: Intl.DateTimeFormatOptions = {}) => {
+  if (!value) return '—'
+  const date = typeof value === 'string' ? new Date(value) : value
+  if (Number.isNaN(date.getTime())) return '—'
+  return new Intl.DateTimeFormat(undefined, {
+    day: '2-digit',
+    month: 'short',
+    year: 'numeric',
+    ...options,
+  }).format(date)
+}
+
+export const formatRelativeDate = (value?: string | Date | null) => {
+  if (!value) return '—'
+  const date = typeof value === 'string' ? new Date(value) : value
+  if (Number.isNaN(date.getTime())) return '—'
+  const formatter = new Intl.RelativeTimeFormat(undefined, { numeric: 'auto' })
+  const diffMs = date.getTime() - Date.now()
+  const diffDays = Math.round(diffMs / (1000 * 60 * 60 * 24))
+  return formatter.format(diffDays, 'day')
+}