diff --git a/create-card.js b/create-card.js
index 731577a..ede85e0 100644
--- a/create-card.js
+++ b/create-card.js
@@ -91,8 +91,10 @@ class CardCreator {
   /**
    * Creates a new card creator.
    * @constructor
+   * @param {string} [xivApiKey] The API key for the XIV API to be used in all requests.
    */
-  constructor() {
+  constructor(xivApiKey = undefined) {
+    this.xivApiKey = typeof xivApiKey === 'string' && xivApiKey !== '' ? xivApiKey : undefined;
     this.isInit = false;
   }
 
diff --git a/index.js b/index.js
index 9261107..99cac18 100644
--- a/index.js
+++ b/index.js
@@ -11,7 +11,7 @@ const xivApiKey = typeof process.env.XIV_API_KEY === 'string' && process.env.XIV
 const supportedLanguages = ['en', 'ja', 'de', 'fr'];
 
 const app = express();
-const creator = new CardCreator();
+const creator = new CardCreator(xivApiKey);
 
 // Initialize caching on disk
 const diskCache = cacheManager.caching({