diff --git a/webui/src/contexts/AuthContext.tsx b/webui/src/contexts/AuthContext.tsx
index 20efa06..d3b8a12 100644
--- a/webui/src/contexts/AuthContext.tsx
+++ b/webui/src/contexts/AuthContext.tsx
@@ -1,4 +1,3 @@
-import { API_BASE } from '@/lib/api'
 import { type ReactNode, createContext, useCallback, useContext, useEffect, useState } from 'react'
 
 interface AuthContextState {
@@ -63,7 +62,7 @@ export const AuthProvider = ({ children }: AuthProviderProps) => {
   // Validate API key by making a test request
   const validateApiKey = async (key: string): Promise<boolean> => {
     try {
-      const response = await fetch(API_BASE + '/instances', {
+      const response = await fetch(document.baseURI + 'api/v1/instances', {
         headers: {
           'Authorization': `Bearer ${key}`,
           'Content-Type': 'application/json'
diff --git a/webui/src/lib/__tests__/api.test.ts b/webui/src/lib/__tests__/api.test.ts
index d7881bc..87e8ac7 100644
--- a/webui/src/lib/__tests__/api.test.ts
+++ b/webui/src/lib/__tests__/api.test.ts
@@ -1,5 +1,5 @@
-import { describe, it, expect, vi, beforeEach } from 'vitest'
 import { instancesApi } from '@/lib/api'
+import { beforeEach, describe, expect, it, vi } from 'vitest'
 
 // Mock fetch globally
 const mockFetch = vi.fn()
@@ -53,7 +53,9 @@ describe('API Error Handling', () => {
     await instancesApi.getLogs('test-instance', 100)
 
     expect(mockFetch).toHaveBeenCalledWith(
-      '/api/v1/instances/test-instance/logs?lines=100',
+      expect.stringMatching(
+        /^https?:\/\/[^/]+\/api\/v1\/instances\/test-instance\/logs\?lines=100$/
+      ),
       expect.any(Object)
     )
   })