diff --git a/frontend/eslint.config.mjs b/frontend/eslint.config.mjs
index 64f7acefd2..b8cbc95a1d 100644
--- a/frontend/eslint.config.mjs
+++ b/frontend/eslint.config.mjs
@@ -59,6 +59,20 @@ export default defineConfig(
       ],
     },
   },
+  // Folders that have been cleaned up and are now conformant - stricter rules enforced here
+  {
+    files: ['src/saas/**/*.{js,mjs,jsx,ts,tsx}'],
+    languageOptions: {
+      parserOptions: {
+        project: true,
+        tsconfigRootDir: import.meta.dirname,
+      },
+    },
+    rules: {
+      '@typescript-eslint/no-explicit-any': 'error',
+      '@typescript-eslint/no-unnecessary-type-assertion': 'error',
+    },
+  },
   // Config for browser scripts
   {
     files: srcGlobs,
diff --git a/frontend/src/global.d.ts b/frontend/src/global.d.ts
index c09d1b3a9b..09487d4a06 100644
--- a/frontend/src/global.d.ts
+++ b/frontend/src/global.d.ts
@@ -12,6 +12,12 @@ declare module 'assets/material-symbols-icons.json' {
   export default value;
 }
 
+declare global {
+  interface Window {
+    __STIRLING_PDF_BASE_URL__?: string;
+  }
+}
+
 declare module 'axios' {
   export interface AxiosRequestConfig<_D = unknown> {
     suppressErrorToast?: boolean;
diff --git a/frontend/src/saas/auth/UseSession.tsx b/frontend/src/saas/auth/UseSession.tsx
index 0de2231676..fd46263694 100644
--- a/frontend/src/saas/auth/UseSession.tsx
+++ b/frontend/src/saas/auth/UseSession.tsx
@@ -114,7 +114,7 @@ export function AuthProvider({ children }: { children: ReactNode }) {
       setSubscription(subscriptionInfo)
 
       console.debug('[Auth Debug] Credits fetched successfully:', credits)
-    } catch (error: any) {
+    } catch (error: unknown) {
       console.debug('[Auth Debug] Failed to fetch credits:', error)
       // Don't set error state for credit fetching failures to avoid disrupting auth flow
       // Credits might not be available in all deployments
@@ -149,7 +149,7 @@ export function AuthProvider({ children }: { children: ReactNode }) {
         setIsPro(isProUser)
         console.debug('[Auth Debug] Pro status fetched:', isProUser)
       }
-    } catch (error: any) {
+    } catch (error: unknown) {
       console.debug('[Auth Debug] Failed to fetch pro status:', error)
       setIsPro(false) // Default to false if there's an error
     }
@@ -206,7 +206,7 @@ export function AuthProvider({ children }: { children: ReactNode }) {
       } else {
         setTrialStatus(null)
       }
-    } catch (error: any) {
+    } catch (error: unknown) {
       console.debug('[Auth Debug] Failed to fetch trial status:', error)
       setTrialStatus(null)
     }
@@ -243,7 +243,7 @@ export function AuthProvider({ children }: { children: ReactNode }) {
         setProfilePictureUrl(data.signedUrl)
         console.debug('[Auth Debug] Profile picture URL fetched successfully')
       }
-    } catch (error: any) {
+    } catch (error: unknown) {
       console.debug('[Auth Debug] Failed to fetch profile picture:', error)
       setProfilePictureUrl(null)
     }
@@ -267,7 +267,7 @@ export function AuthProvider({ children }: { children: ReactNode }) {
       const metadata = await getProfilePictureMetadata(currentSession.user.id)
       setProfilePictureMetadata(metadata)
       console.debug('[Auth Debug] Profile picture metadata fetched:', metadata)
-    } catch (error: any) {
+    } catch (error: unknown) {
       console.debug('[Auth Debug] Failed to fetch profile picture metadata:', error)
       setProfilePictureMetadata(null)
     }
diff --git a/frontend/src/saas/auth/supabase.ts b/frontend/src/saas/auth/supabase.ts
index b8b473f785..338c5c8adc 100644
--- a/frontend/src/saas/auth/supabase.ts
+++ b/frontend/src/saas/auth/supabase.ts
@@ -83,7 +83,7 @@ export const signInAnonymously = async () => {
 // Account linking functions
 export const linkEmailIdentity = async (email: string, password?: string) => {
   try {
-    const updateData: any = { email }
+    const updateData: { email: string; password?: string } = { email }
     if (password) {
       updateData.password = password
     }
@@ -143,7 +143,7 @@ export const linkOAuthIdentity = async (provider: 'google' | 'github' | 'apple'
 }
 
 // Helper function to check if user is anonymous
-export const isUserAnonymous = (user: any) => {
+export const isUserAnonymous = (user: { is_anonymous?: boolean }) => {
   return user?.is_anonymous === true
 }
 
diff --git a/frontend/src/saas/components/shared/ManageBillingButton.tsx b/frontend/src/saas/components/shared/ManageBillingButton.tsx
index 507aeb07e0..3f9558bbf3 100644
--- a/frontend/src/saas/components/shared/ManageBillingButton.tsx
+++ b/frontend/src/saas/components/shared/ManageBillingButton.tsx
@@ -38,16 +38,16 @@ export function ManageBillingButton({
     setLoading(true);
     setErr(null);
     try {
-      const { data, error } = await supabase.functions.invoke('manage-billing', {
+      const { data, error } = await supabase.functions.invoke<{ url: string; error?: string }>('manage-billing', {
         body: {
         name: 'Functions',
         return_url: returnUrl},
       })
       if (error) throw error;
-      if (!data || 'error' in data) throw new Error((data as any)?.error ?? 'No portal URL');
-      window.location.href = (data as any).url;
-    } catch (e: any) {
-      setErr(e.message ?? 'Could not open billing portal');
+      if (!data || 'error' in data) throw new Error(data?.error ?? 'No portal URL');
+      window.location.href = data.url;
+    } catch (e: unknown) {
+      setErr(e instanceof Error ? e.message : 'Could not open billing portal');
     } finally {
       setLoading(false);
     }
diff --git a/frontend/src/saas/components/shared/StripeCheckoutSaas.tsx b/frontend/src/saas/components/shared/StripeCheckoutSaas.tsx
index 61c164b236..27f1f1abc3 100644
--- a/frontend/src/saas/components/shared/StripeCheckoutSaas.tsx
+++ b/frontend/src/saas/components/shared/StripeCheckoutSaas.tsx
@@ -24,7 +24,7 @@ interface StripeCheckoutProps {
   currency?: string;
   isTrialConversion?: boolean;
   // Proprietary-specific props (for compatibility)
-  planGroup?: any;
+  planGroup?: unknown;
   minimumSeats?: number;
   onLicenseActivated?: (licenseInfo: {licenseType: string; enabled: boolean; maxUsers: number; hasKey: boolean}) => void;
   hostedCheckoutSuccess?: {
diff --git a/frontend/src/saas/components/shared/charts/utils/d3Utils.ts b/frontend/src/saas/components/shared/charts/utils/d3Utils.ts
index 44b5b50988..ddeed92197 100644
--- a/frontend/src/saas/components/shared/charts/utils/d3Utils.ts
+++ b/frontend/src/saas/components/shared/charts/utils/d3Utils.ts
@@ -162,7 +162,7 @@ export function createScale(domain: [number, number], range: [number, number]) {
  * @param wait The wait time in milliseconds
  * @returns Debounced function
  */
-export function debounce<T extends (...args: any[]) => any>(
+export function debounce<T extends (...args: unknown[]) => unknown>(
   func: T,
   wait: number
 ): (...args: Parameters<T>) => void {
diff --git a/frontend/src/saas/components/shared/config/configSections/Overview.tsx b/frontend/src/saas/components/shared/config/configSections/Overview.tsx
index 90e89c6768..d535fdc2a7 100644
--- a/frontend/src/saas/components/shared/config/configSections/Overview.tsx
+++ b/frontend/src/saas/components/shared/config/configSections/Overview.tsx
@@ -149,8 +149,8 @@ const Overview: React.FC<OverviewProps> = ({ onLogoutClick }) => {
 
       // Clear success message after 3 seconds
       setTimeout(() => setSuccess(null), 3000);
-    } catch (error: any) {
-      setProfileError(error.message || 'Failed to switch to custom picture');
+    } catch (error: unknown) {
+      setProfileError(error instanceof Error ? error.message : 'Failed to switch to custom picture');
     } finally {
       setProfileUploading(false);
     }
@@ -181,8 +181,8 @@ const Overview: React.FC<OverviewProps> = ({ onLogoutClick }) => {
       setSuccess('Account upgraded successfully! You can now sign in with your email.');
       setEmail('');
       setPassword('');
-    } catch (err: any) {
-      setUpgradeError(err?.message || 'Failed to upgrade account');
+    } catch (err: unknown) {
+      setUpgradeError(err instanceof Error ? err.message : 'Failed to upgrade account');
     } finally {
       setIsLoading(false);
     }
@@ -404,7 +404,7 @@ const Overview: React.FC<OverviewProps> = ({ onLogoutClick }) => {
                           style={{ width: 16, height: 16 }}
                         />
                       }
-                      onClick={() => handleOAuthUpgrade(provider.id as any)}
+                      onClick={() => handleOAuthUpgrade(provider.id as 'github' | 'google' | 'apple' | 'azure')}
                       disabled={isLoading}
                     >
                       {provider.label}
diff --git a/frontend/src/saas/components/shared/config/configSections/PasswordSecurity.tsx b/frontend/src/saas/components/shared/config/configSections/PasswordSecurity.tsx
index e0ff18ddc4..55ab3cdc2b 100644
--- a/frontend/src/saas/components/shared/config/configSections/PasswordSecurity.tsx
+++ b/frontend/src/saas/components/shared/config/configSections/PasswordSecurity.tsx
@@ -55,8 +55,8 @@ const PasswordSecurity: React.FC = () => {
         setOpened(false);
         setDidUpdate(false);
       }, 2000);
-    } catch (e: any) {
-      setError(e?.message || 'Failed to change password');
+    } catch (e: unknown) {
+      setError(e instanceof Error ? e.message : 'Failed to change password');
     } finally {
       setIsLoading(false);
     }
diff --git a/frontend/src/saas/components/shared/config/configSections/apiKeys/hooks/useApiKey.ts b/frontend/src/saas/components/shared/config/configSections/apiKeys/hooks/useApiKey.ts
index 22e4c51714..870700eb26 100644
--- a/frontend/src/saas/components/shared/config/configSections/apiKeys/hooks/useApiKey.ts
+++ b/frontend/src/saas/components/shared/config/configSections/apiKeys/hooks/useApiKey.ts
@@ -1,8 +1,11 @@
 import { useCallback, useEffect, useState } from "react";
+import { isAxiosError } from "axios";
 import apiClient from "@app/services/apiClient";
 import { useAuth } from "@app/auth/UseSession";
 import { isUserAnonymous } from "@app/auth/supabase";
 
+type ApiKeyResponse = string | { apiKey?: string };
+
 export function useApiKey() {
   const { session, loading, user } = useAuth();
   const isAnonymous = Boolean(user && isUserAnonymous(user));
@@ -17,24 +20,21 @@ export function useApiKey() {
     setError(null);
     try {
       // Backend is POST for get and update
-      const res = await apiClient.post("/api/v1/user/get-api-key");
-      const value = typeof res.data === "string" ? res.data : res.data?.apiKey;
+      const res = await apiClient.post<ApiKeyResponse>("/api/v1/user/get-api-key");
+      const value = typeof res.data === "string" ? res.data : res.data.apiKey;
       if (typeof value === "string") setApiKey(value);
-    } catch (e: any) {
+    } catch (e: unknown) {
       // If not found, try to create one by calling update endpoint
-      if (e?.response?.status === 404) {
+      if (isAxiosError(e) && e.response?.status === 404) {
         try {
-          const createRes = await apiClient.post("/api/v1/user/update-api-key");
-          const created =
-            typeof createRes.data === "string"
-              ? createRes.data
-              : createRes.data?.apiKey;
+          const createRes = await apiClient.post<ApiKeyResponse>("/api/v1/user/update-api-key");
+          const created = typeof createRes.data === "string" ? createRes.data : createRes.data.apiKey;
           if (typeof created === "string") setApiKey(created);
-        } catch (createErr: any) {
-          setError(createErr);
+        } catch (createErr: unknown) {
+          setError(createErr instanceof Error ? createErr : new Error(String(createErr)));
         }
       } else {
-        setError(e);
+        setError(e instanceof Error ? e : new Error(String(e)));
       }
     } finally {
       setIsLoading(false);
@@ -46,11 +46,11 @@ export function useApiKey() {
     setIsRefreshing(true);
     setError(null);
     try {
-      const res = await apiClient.post("/api/v1/user/update-api-key");
-      const value = typeof res.data === "string" ? res.data : res.data?.apiKey;
+      const res = await apiClient.post<ApiKeyResponse>("/api/v1/user/update-api-key");
+      const value = typeof res.data === "string" ? res.data : res.data.apiKey;
       if (typeof value === "string") setApiKey(value);
-    } catch (e: any) {
-      setError(e);
+    } catch (e: unknown) {
+      setError(e instanceof Error ? e : new Error(String(e)));
     } finally {
       setIsRefreshing(false);
     }
diff --git a/frontend/src/saas/components/shared/config/configSections/apiKeys/hooks/useCredits.ts b/frontend/src/saas/components/shared/config/configSections/apiKeys/hooks/useCredits.ts
index 1b52e1b0f3..20c0a93866 100644
--- a/frontend/src/saas/components/shared/config/configSections/apiKeys/hooks/useCredits.ts
+++ b/frontend/src/saas/components/shared/config/configSections/apiKeys/hooks/useCredits.ts
@@ -6,10 +6,10 @@ import { isUserAnonymous } from "@app/auth/supabase";
 
 function coerceNumber(value: unknown, fallback = 0): number {
   const n = typeof value === "string" ? Number(value) : (value as number);
-  return Number.isFinite(n) ? (n as number) : fallback;
+  return Number.isFinite(n) ? n : fallback;
 }
 
-function normalizeCredits(raw: any): ApiCredits {
+function normalizeCredits(raw: Record<string, unknown>): ApiCredits {
   // Accept a variety of possible backend keys to be resilient
   return {
     weeklyCreditsRemaining: coerceNumber(
@@ -28,9 +28,9 @@ function normalizeCredits(raw: any): ApiCredits {
       raw?.totalAvailableCredits ?? raw?.totalRemaining ?? raw?.available_total
     ),
     weeklyResetDate:
-      (raw?.weeklyResetDate ?? raw?.weeklyReset ?? raw?.reset_date) || "",
+      String(raw?.weeklyResetDate ?? raw?.weeklyReset ?? raw?.reset_date ?? ""),
     lastApiUsage:
-      (raw?.lastApiUsage ?? raw?.lastApiUse ?? raw?.last_used_at) || "",
+      String(raw?.lastApiUsage ?? raw?.lastApiUse ?? raw?.last_used_at ?? ""),
   };
 }
 
@@ -46,7 +46,7 @@ export function useCredits() {
     setIsLoading(true);
     setError(null);
     try {
-      const res = await apiClient.get("/api/v1/credits");
+      const res = await apiClient.get<Record<string, unknown>>("/api/v1/credits");
       const normalized = normalizeCredits(res.data);
       // If backend returns an "empty" payload, keep data null so the UI stays in loading/skeleton
       const isEmpty = !normalized.weeklyCreditsAllocated &&
@@ -57,8 +57,8 @@ export function useCredits() {
                       !normalized.weeklyResetDate &&
                       !normalized.lastApiUsage;
       setData(isEmpty ? null : normalized);
-    } catch (e: any) {
-      setError(e);
+    } catch (e: unknown) {
+      setError(e instanceof Error ? e : new Error(String(e)));
     } finally {
       setIsLoading(false);
       setHasAttempted(true);
diff --git a/frontend/src/saas/components/shared/config/configSections/plan/AvailablePlansSection.tsx b/frontend/src/saas/components/shared/config/configSections/plan/AvailablePlansSection.tsx
index 25f4322f0a..c8fd19321a 100644
--- a/frontend/src/saas/components/shared/config/configSections/plan/AvailablePlansSection.tsx
+++ b/frontend/src/saas/components/shared/config/configSections/plan/AvailablePlansSection.tsx
@@ -7,9 +7,9 @@ import PlanCard from '@app/components/shared/config/configSections/plan/PlanCard
 interface AvailablePlansSectionProps {
   plans: PlanTier[];
   currentPlan?: PlanTier;
-  currentLicenseInfo?: any;
-  onUpgradeClick: (plan: PlanTier | any) => void;  // Accept PlanTierGroup for compatibility
-  onManageClick?: (plan: PlanTier | any) => void;  // Accept PlanTierGroup for compatibility
+  currentLicenseInfo?: unknown;
+  onUpgradeClick: (plan: PlanTier) => void;
+  onManageClick?: (plan: PlanTier) => void;
   currency?: string;
   onCurrencyChange?: (currency: string) => void;
   currencyOptions?: Array<{ value: string; label: string }>;
diff --git a/frontend/src/saas/components/shared/config/configSections/plan/PlanCard.tsx b/frontend/src/saas/components/shared/config/configSections/plan/PlanCard.tsx
index 9551f358fb..de02c959ab 100644
--- a/frontend/src/saas/components/shared/config/configSections/plan/PlanCard.tsx
+++ b/frontend/src/saas/components/shared/config/configSections/plan/PlanCard.tsx
@@ -5,15 +5,15 @@ import { PlanTier } from '@app/hooks/usePlans';
 
 interface PlanCardProps {
   plan?: PlanTier;
-  planGroup?: any;  // For proprietary PlanTierGroup compatibility
+  planGroup?: { monthly?: PlanTier; yearly?: PlanTier };  // For proprietary PlanTierGroup compatibility
   isCurrentPlan?: boolean;
   isCurrentTier?: boolean;
   isDowngrade?: boolean;
   isUserProOrAbove?: boolean;
-  currentLicenseInfo?: any;
+  currentLicenseInfo?: unknown;
   currentTier?: string | null;  // Accept null for proprietary compatibility
-  onUpgradeClick?: (plan: any) => void;  // Accept PlanTierGroup or PlanTier
-  onManageClick?: (plan: any) => void;
+  onUpgradeClick?: (plan: PlanTier) => void;
+  onManageClick?: (plan: PlanTier) => void;
   loginEnabled?: boolean;
 }
 
@@ -31,7 +31,7 @@ const PlanCard: React.FC<PlanCardProps> = ({
   loginEnabled: _loginEnabled
 }) => {
   // Use plan from props, or extract from planGroup if proprietary is using it
-  const plan = propPlan || (planGroup as any)?.monthly || (planGroup as any)?.yearly;
+  const plan = propPlan || planGroup?.monthly || planGroup?.yearly;
   const { t } = useTranslation();
 
   if (!plan) return null; // Safety check
diff --git a/frontend/src/saas/constants/app.ts b/frontend/src/saas/constants/app.ts
index dbe845aaed..90a130c76c 100644
--- a/frontend/src/saas/constants/app.ts
+++ b/frontend/src/saas/constants/app.ts
@@ -5,11 +5,10 @@ export * from '@core/constants/app';
 // Get base URL with fallback (for use outside React components)
 export const getBaseUrl = (): string => {
   // Try to get from window object if set by app config
-  const baseUrl = (window as any).__STIRLING_PDF_BASE_URL__ || window.location.origin;
-  return baseUrl;
+  return window.__STIRLING_PDF_BASE_URL__ || window.location.origin;
 };
 
 // Helper to set base URL (to be called when app config loads)
 export const setBaseUrl = (url: string): void => {
-  (window as any).__STIRLING_PDF_BASE_URL__ = url;
+  window.__STIRLING_PDF_BASE_URL__ = url;
 };
diff --git a/frontend/src/saas/hooks/useEndpointConfig.ts b/frontend/src/saas/hooks/useEndpointConfig.ts
index 5da0fdd2af..c98dec5966 100644
--- a/frontend/src/saas/hooks/useEndpointConfig.ts
+++ b/frontend/src/saas/hooks/useEndpointConfig.ts
@@ -1,4 +1,5 @@
 import { useState, useEffect } from 'react';
+import { isAxiosError } from 'axios';
 import apiClient from '@app/services/apiClient';
 import type { EndpointAvailabilityDetails } from '@app/types/endpointAvailability';
 
@@ -153,9 +154,9 @@ export function useMultipleEndpointsEnabled(endpoints: string[]): {
       setEndpointStatus(fullStatus.status);
       setEndpointDetails(prev => ({ ...prev, ...fullStatus.details }));
       globalFetchedSets.add(endpointsKey);
-    } catch (err: any) {
+    } catch (err: unknown) {
       // On 401 (auth error), use optimistic fallback instead of disabling
-      if (err.response?.status === 401) {
+      if (isAxiosError(err) && err.response?.status === 401) {
         console.warn('[useEndpointConfig] 401 error - using optimistic fallback');
         const optimisticStatus = endpoints.reduce(
           (acc, endpoint) => {
diff --git a/frontend/src/saas/routes/AuthCallback.tsx b/frontend/src/saas/routes/AuthCallback.tsx
index 8738a64509..7b596d7858 100644
--- a/frontend/src/saas/routes/AuthCallback.tsx
+++ b/frontend/src/saas/routes/AuthCallback.tsx
@@ -7,7 +7,7 @@ import { withBasePath } from '@app/constants/app'
 interface CallbackState {
   status: 'processing' | 'success' | 'error'
   message: string
-  details?: Record<string, any>
+  details?: Record<string, unknown>
 }
 
 export default function AuthCallback() {
diff --git a/frontend/src/saas/routes/Login.tsx b/frontend/src/saas/routes/Login.tsx
index 9347cfeef9..6a0109d583 100644
--- a/frontend/src/saas/routes/Login.tsx
+++ b/frontend/src/saas/routes/Login.tsx
@@ -68,7 +68,7 @@ export default function Login() {
       const redirectTo = absoluteWithBasePath('/auth/callback')
       console.log(`[Login] Signing in with ${provider}`)
 
-      const oauthOptions: any = { redirectTo }
+      const oauthOptions: { redirectTo: string; queryParams?: Record<string, string> } = { redirectTo }
       if (provider === 'apple') {
         oauthOptions.queryParams = { scope: 'email name' }
       } else if (provider === 'azure') {
@@ -175,12 +175,9 @@ export default function Login() {
       setError(null)
       console.log('[Login] Signing in anonymously')
 
-      const { data, error } = await signInAnonymously()
+      const { data } = await signInAnonymously()
 
-      if (error) {
-        console.error('[Login] Anonymous sign in error:', error)
-        setError((error as any)?.message || 'Unknown error')
-      } else if (data.user) {
+      if (data.user) {
         console.log('[Login] Anonymous sign in successful, refreshing session...')
 
         // Refresh session to ensure backend endpoints are properly synchronized
diff --git a/frontend/src/saas/routes/Signup.tsx b/frontend/src/saas/routes/Signup.tsx
index 94df229650..24a83c0c5f 100644
--- a/frontend/src/saas/routes/Signup.tsx
+++ b/frontend/src/saas/routes/Signup.tsx
@@ -62,12 +62,9 @@ export default function Signup() {
       setError(null)
 
       console.log('[Signup] Initiating anonymous sign-in...')
-      const { data, error } = await signInAnonymously()
+      const { data } = await signInAnonymously()
 
-      if (error) {
-        console.error('[Signup] Anonymous sign-in error:', error)
-        setError(`Failed to create guest account: ${(error as any)?.message || 'Unknown error'}`)
-      } else if (data.user) {
+      if (data.user) {
         console.log('[Signup] Anonymous sign-in successful, refreshing session...')
 
         // Refresh session to ensure backend endpoints are properly synchronized
diff --git a/frontend/src/saas/routes/login/OAuthButtons.tsx b/frontend/src/saas/routes/login/OAuthButtons.tsx
index aeb6c337e6..e53bd3cf06 100644
--- a/frontend/src/saas/routes/login/OAuthButtons.tsx
+++ b/frontend/src/saas/routes/login/OAuthButtons.tsx
@@ -32,7 +32,7 @@ export default function OAuthButtons({ onProviderClick, isSubmitting, layout = '
             position="top"
           >
             <button
-              onClick={() => onProviderClick(p.id as any)}
+              onClick={() => onProviderClick(p.id as 'github' | 'google')}
               disabled={isSubmitting || p.isDisabled}
               className="oauth-button-icon"
               aria-label={`${t('login.signInWith', 'Sign in with')} ${p.label}`}
@@ -55,7 +55,7 @@ export default function OAuthButtons({ onProviderClick, isSubmitting, layout = '
             position="top"
           >
             <button
-              onClick={() => onProviderClick(p.id as any)}
+              onClick={() => onProviderClick(p.id as 'github' | 'google')}
               disabled={isSubmitting || p.isDisabled}
               className="oauth-button-grid"
               aria-label={`${t('login.signInWith', 'Sign in with')} ${p.label}`}
@@ -74,7 +74,7 @@ export default function OAuthButtons({ onProviderClick, isSubmitting, layout = '
         {oauthProviders.map((p) => (
           <button
             key={p.id}
-            onClick={() => onProviderClick(p.id as any)}
+            onClick={() => onProviderClick(p.id as 'github' | 'google')}
             disabled={isSubmitting || p.isDisabled}
             className="oauth-button-fullwidth"
             title={p.label}
@@ -92,7 +92,7 @@ export default function OAuthButtons({ onProviderClick, isSubmitting, layout = '
       {oauthProviders.map((p) => (
         <button
           key={p.id}
-          onClick={() => onProviderClick(p.id as any)}
+          onClick={() => onProviderClick(p.id as 'github' | 'google')}
           disabled={isSubmitting || p.isDisabled}
           className="oauth-button-vertical"
           title={p.label}
diff --git a/frontend/src/saas/services/apiClient.test.ts b/frontend/src/saas/services/apiClient.test.ts
index 5858e2c436..1e481bf022 100644
--- a/frontend/src/saas/services/apiClient.test.ts
+++ b/frontend/src/saas/services/apiClient.test.ts
@@ -1,4 +1,5 @@
 import { describe, it, expect, vi, beforeEach } from 'vitest';
+import type { Session, AuthError } from '@supabase/supabase-js';
 import { supabase } from '@app/auth/supabase';
 
 // Mock supabase
@@ -20,13 +21,13 @@ describe('apiClient', () => {
 
   it('should add JWT token to request headers when session exists', async () => {
     const mockToken = 'test-jwt-token-12345';
-    const mockSession: any = {
+    const mockSession = {
       access_token: mockToken,
       refresh_token: 'refresh-token',
       expires_in: 3600,
       token_type: 'bearer',
       user: { id: 'user-123' },
-    };
+    } as unknown as Session;
 
     // Mock getSession to return a session with token
     vi.mocked(supabase.auth.getSession).mockResolvedValue({
@@ -99,21 +100,21 @@ describe('apiClient', () => {
     const oldToken = 'old-token';
     const newToken = 'new-refreshed-token';
 
-    const oldSession: any = {
+    const oldSession = {
       access_token: oldToken,
       refresh_token: 'refresh-token',
       expires_in: 3600,
       token_type: 'bearer',
       user: { id: 'user-123' },
-    };
+    } as unknown as Session;
 
-    const newSession: any = {
+    const newSession = {
       access_token: newToken,
       refresh_token: 'new-refresh-token',
       expires_in: 3600,
       token_type: 'bearer',
       user: { id: 'user-123' },
-    };
+    } as unknown as Session;
 
     // Mock initial session for first request
     let getSessionCallCount = 0;
@@ -129,8 +130,8 @@ describe('apiClient', () => {
     // Mock refresh to return new session
     vi.mocked(supabase.auth.refreshSession).mockResolvedValue({
       data: { user: null, session: newSession },
-      error: null as any,
-    } as any);
+      error: null,
+    });
 
     // Import apiClient after mocking
     const { default: apiClient } = await import('@app/services/apiClient');
@@ -143,12 +144,10 @@ describe('apiClient', () => {
       if (requestCount === 1) {
         // Verify first request has old token
         expect(config.headers.Authorization).toBe(`Bearer ${oldToken}`);
-        const error: any = new Error('Unauthorized');
-        error.response = {
-          status: 401,
-          data: { error: 'Unauthorized' },
-        };
-        error.config = config;
+        const error = Object.assign(new Error('Unauthorized'), {
+          response: { status: 401, data: { error: 'Unauthorized' } },
+          config,
+        });
         return Promise.reject(error);
       }
 
@@ -187,35 +186,32 @@ describe('apiClient', () => {
 
     // Mock initial session
     vi.mocked(supabase.auth.getSession).mockResolvedValue({
-      data: { session: oldSession },
+      data: { session: oldSession as unknown as Session },
       error: null,
-    } as any);
+    });
     vi.mocked(supabase.auth.getSession).mockResolvedValue({
-      data: { session: oldSession },
+      data: { session: oldSession as unknown as Session },
       error: null,
-    } as any);
+    });
 
     // Mock refresh to fail
     vi.mocked(supabase.auth.refreshSession).mockResolvedValue({
       data: { user: null, session: null },
-      error: { name: 'AuthError', message: 'Refresh failed', status: 400, code: 'auth_error', __isAuthError: true } as any,
-    } as any);
+      error: { name: 'AuthError', message: 'Refresh failed', status: 400, code: 'auth_error' } as unknown as AuthError,
+    });
 
     // Import apiClient after mocking
     const { default: apiClient } = await import('@app/services/apiClient');
 
     // Mock window.location for redirect test
-    delete (window as any).location;
-    window.location = { href: '' } as any;
+    Object.defineProperty(window, 'location', { writable: true, value: { href: '' } });
 
     const mockAdapter = vi.fn((config) => {
       // Always return 401 to trigger refresh
-      const error: any = new Error('Unauthorized');
-      error.response = {
-        status: 401,
-        data: { error: 'Unauthorized' },
-      };
-      error.config = config;
+      const error = Object.assign(new Error('Unauthorized'), {
+        response: { status: 401, data: { error: 'Unauthorized' } },
+        config,
+      });
       return Promise.reject(error);
     });
 
diff --git a/frontend/src/saas/services/userManagementService.ts b/frontend/src/saas/services/userManagementService.ts
index f72fe0696e..3c94ecb31d 100644
--- a/frontend/src/saas/services/userManagementService.ts
+++ b/frontend/src/saas/services/userManagementService.ts
@@ -31,7 +31,7 @@ export interface AdminSettingsData {
   disabledUsers: number;
   currentUsername?: string;
   roleDetails?: Record<string, string>;
-  teams?: any[];
+  teams?: Array<{ id: number; name: string; [key: string]: unknown }>;
   maxPaidUsers?: number;
   // License information
   maxAllowedUsers: number;
@@ -138,7 +138,7 @@ export const userManagementService = {
     }
     await apiClient.post('/api/v1/user/admin/saveUser', formData, {
       suppressErrorToast: true, // Component will handle error display
-    } as any);
+    });
   },
 
   /**
@@ -153,7 +153,7 @@ export const userManagementService = {
     }
     await apiClient.post('/api/v1/user/admin/changeRole', formData, {
       suppressErrorToast: true,
-    } as any);
+    });
   },
 
   /**
@@ -164,7 +164,7 @@ export const userManagementService = {
     formData.append('enabled', enabled.toString());
     await apiClient.post(`/api/v1/user/admin/changeUserEnabled/${username}`, formData, {
       suppressErrorToast: true,
-    } as any);
+    });
   },
 
   /**
@@ -208,7 +208,7 @@ export const userManagementService = {
       formData,
       {
         suppressErrorToast: true, // Component will handle error display
-      } as any
+      }
     );
 
     return response.data;
@@ -239,7 +239,7 @@ export const userManagementService = {
       formData,
       {
         suppressErrorToast: true,
-      } as any
+      }
     );
 
     return response.data;
@@ -259,7 +259,7 @@ export const userManagementService = {
   async revokeInviteLink(inviteId: number): Promise<void> {
     await apiClient.delete(`/api/v1/invite/revoke/${inviteId}`, {
       suppressErrorToast: true,
-    } as any);
+    });
   },
 
   /**
diff --git a/frontend/src/saas/setupTests.ts b/frontend/src/saas/setupTests.ts
index ce2532f47a..f2ecbb7ca6 100644
--- a/frontend/src/saas/setupTests.ts
+++ b/frontend/src/saas/setupTests.ts
@@ -89,15 +89,16 @@ for (let i = 0; i < 32; i++) {
 Object.defineProperty(globalThis, 'crypto', {
   value: {
     subtle: {
-      digest: vi.fn().mockImplementation(async (_algorithm: string, _data: any) => {
+      digest: vi.fn().mockImplementation(async (_algorithm: string, _data: BufferSource) => {
         // Always return the mock hash buffer regardless of input
         return mockHashBuffer.slice();
       }),
     },
-    getRandomValues: vi.fn().mockImplementation((array: any) => {
+    getRandomValues: vi.fn().mockImplementation(<T extends ArrayBufferView>(array: T): T => {
       // Mock getRandomValues if needed
-      for (let i = 0; i < array.length; i++) {
-        array[i] = Math.floor(Math.random() * 256);
+      const view = new Uint8Array(array.buffer, array.byteOffset, array.byteLength);
+      for (let i = 0; i < view.length; i++) {
+        view[i] = Math.floor(Math.random() * 256);
       }
       return array;
     }),