diff --git a/src/utils/encodeQR.ts b/src/utils/encodeQR.ts
new file mode 100644
index 0000000..be67f53
--- /dev/null
+++ b/src/utils/encodeQR.ts
@@ -0,0 +1,71 @@
+import type { QRState } from '../types';
+
+export function encodeQR(state: QRState): string | null {
+  const { selectedType, formData } = state;
+
+  switch (selectedType) {
+    case 'url': {
+      const { websiteUrl } = formData.url;
+      return websiteUrl.trim() || null;
+    }
+    case 'text': {
+      const { text } = formData.text;
+      return text.trim() || null;
+    }
+    case 'wifi': {
+      const { networkName, encryption, password } = formData.wifi;
+      if (!networkName.trim()) return null;
+      const pass = encryption === 'None' ? '' : password;
+      return `WIFI:T:${encryption};S:${networkName};P:${pass};;`;
+    }
+    case 'email': {
+      const { emailAddress, subject, message } = formData.email;
+      if (!emailAddress.trim()) return null;
+      const params = new URLSearchParams();
+      if (subject.trim()) params.set('subject', subject);
+      if (message.trim()) params.set('body', message);
+      const qs = params.toString();
+      return `mailto:${emailAddress}${qs ? '?' + qs : ''}`;
+    }
+    case 'sms': {
+      const { phoneNumber, message } = formData.sms;
+      if (!phoneNumber.trim()) return null;
+      return `smsto:${phoneNumber}${message.trim() ? ':' + message : ''}`;
+    }
+    case 'image': {
+      const { imageUrl } = formData.image;
+      return imageUrl.trim() || null;
+    }
+    case 'pdf': {
+      const { pdfUrl } = formData.pdf;
+      return pdfUrl.trim() || null;
+    }
+    case 'mp3': {
+      const { mp3Url } = formData.mp3;
+      return mp3Url.trim() || null;
+    }
+    case 'app': {
+      const { appStoreLink } = formData.app;
+      return appStoreLink.trim() || null;
+    }
+    case 'vcard': {
+      const { firstName, lastName, phone, email, company, jobTitle, website, address } = formData.vcard;
+      if (!firstName.trim() && !lastName.trim()) return null;
+      const lines = [
+        'BEGIN:VCARD', 'VERSION:3.0',
+        `N:${lastName};${firstName};;;`,
+        `FN:${firstName} ${lastName}`.trim(),
+        company ? `ORG:${company}` : '',
+        jobTitle ? `TITLE:${jobTitle}` : '',
+        phone ? `TEL;TYPE=CELL:${phone}` : '',
+        email ? `EMAIL:${email}` : '',
+        website ? `URL:${website}` : '',
+        address ? `ADR:;;${address};;;;` : '',
+        'END:VCARD',
+      ].filter(Boolean);
+      return lines.join('\n');
+    }
+    default:
+      return null;
+  }
+}