diff --git a/src/api/aisClient.ts b/src/api/aisClient.ts
index 116903b..b6d4184 100644
--- a/src/api/aisClient.ts
+++ b/src/api/aisClient.ts
@@ -1,13 +1,21 @@
 import axios from 'axios';
 import type { VesselData } from '../types';
 
-// Using MarineTraffic API as an example - you'll need to add your API key
-const API_KEY = import.meta.env.VITE_MARINE_TRAFFIC_API_KEY;
 const API_BASE_URL = 'https://services.marinetraffic.com/api/vesselmasterdata/v3';
 
+// Get API key at request time to ensure window.env is populated
+const getApiKey = (): string | undefined => {
+  if (typeof window !== 'undefined' && window.env?.MARINE_TRAFFIC_API_KEY) {
+    return window.env.MARINE_TRAFFIC_API_KEY;
+  }
+  return import.meta.env.VITE_MARINE_TRAFFIC_API_KEY;
+};
+
 export async function getVesselData(imo: string): Promise<VesselData> {
+  const apiKey = getApiKey(); // Lazy evaluate at request time
+
   // For development, return mock data if no API key is present
-  if (!API_KEY) {
+  if (!apiKey) {
     console.warn('No API key found - using mock data');
     return getMockVesselData(imo);
   }
@@ -16,7 +24,7 @@ export async function getVesselData(imo: string): Promise<VesselData> {
     const response = await axios.get(API_BASE_URL, {
       params: {
         imo,
-        apikey: API_KEY,
+        apikey: apiKey,
       }
     });
     
diff --git a/src/api/checkoutClient.ts b/src/api/checkoutClient.ts
index 4a83b55..2785187 100644
--- a/src/api/checkoutClient.ts
+++ b/src/api/checkoutClient.ts
@@ -2,6 +2,8 @@ import axios from 'axios';
 import { logger } from '../utils/logger';
 
 // Get API base URL from runtime config (window.env) or build-time config
+// IMPORTANT: Call this function at REQUEST TIME, not at module load time,
+// to ensure window.env is populated by env-config.js
 const getApiBaseUrl = (): string => {
   // Check window.env first (runtime config from env.sh)
   if (typeof window !== 'undefined' && window.env?.API_BASE_URL) {
@@ -12,8 +14,6 @@ const getApiBaseUrl = (): string => {
   return import.meta.env.VITE_API_BASE_URL || 'http://localhost:3001';
 };
 
-const API_BASE_URL = getApiBaseUrl();
-
 export interface CreateCheckoutSessionParams {
   tons: number;
   portfolioId: number;
@@ -54,10 +54,12 @@ export async function createCheckoutSession(
   params: CreateCheckoutSessionParams
 ): Promise<CheckoutSessionResponse> {
   try {
+    const apiBaseUrl = getApiBaseUrl(); // Lazy evaluate at request time
     logger.info('Creating checkout session:', params);
+    logger.info('Using API base URL:', apiBaseUrl);
 
     const response = await axios.post<CheckoutSessionResponse>(
-      `${API_BASE_URL}/api/checkout/create-session`,
+      `${apiBaseUrl}/api/checkout/create-session`,
       params
     );
 
@@ -79,10 +81,11 @@ export async function createCheckoutSession(
  */
 export async function getOrderDetails(sessionId: string): Promise<OrderDetails> {
   try {
+    const apiBaseUrl = getApiBaseUrl(); // Lazy evaluate at request time
     logger.info('Fetching order details for session:', sessionId);
 
     const response = await axios.get<OrderDetails>(
-      `${API_BASE_URL}/api/checkout/session/${sessionId}`
+      `${apiBaseUrl}/api/checkout/session/${sessionId}`
     );
 
     logger.info('Order details retrieved:', response.data.order.id);
@@ -102,7 +105,8 @@ export async function getOrderDetails(sessionId: string): Promise<OrderDetails>
  */
 export async function checkBackendHealth(): Promise<boolean> {
   try {
-    const response = await axios.get(`${API_BASE_URL}/health`);
+    const apiBaseUrl = getApiBaseUrl(); // Lazy evaluate at request time
+    const response = await axios.get(`${apiBaseUrl}/health`);
     return response.data.status === 'ok';
   } catch (error) {
     logger.error('Backend health check failed:', error);