diff --git a/src/email-digest/email-digest.service.spec.ts b/src/email-digest/email-digest.service.spec.ts
index 7134080e..e1cfdf02 100644
--- a/src/email-digest/email-digest.service.spec.ts
+++ b/src/email-digest/email-digest.service.spec.ts
@@ -1,3 +1,11 @@
+jest.mock('@prisma/client', () => ({
+  ...jest.requireActual('@prisma/client'),
+  DigestFrequency: {
+    DAILY: 'DAILY',
+    WEEKLY: 'WEEKLY',
+  },
+}));
+
 import { EmailDigestService } from './email-digest.service';
 import { PrismaService } from '../database/prisma.service';
 import { EmailService } from '../email/email.service';
@@ -6,18 +14,38 @@ import { ConfigService } from '@nestjs/config';
 describe('EmailDigestService', () => {
   let service: EmailDigestService;
   let prisma: jest.Mocked<Partial<PrismaService>>;
+  let emailService: { sendEmail: jest.Mock };
+  let configService: { get: jest.Mock };
 
   beforeEach(() => {
     prisma = {
       digestPreference: {
-        upsert: jest.fn().mockResolvedValue({ userId: 'u1', enabled: true, frequency: 'DAILY', unsubscribeToken: 'tok' }),
+        upsert: jest.fn().mockResolvedValue({
+          userId: 'u1',
+          enabled: true,
+          frequency: 'DAILY',
+          unsubscribeToken: 'tok',
+        }),
         findUnique: jest.fn().mockResolvedValue(null),
       } as any,
+      notification: {
+        findMany: jest.fn().mockResolvedValue([
+          {
+            title: 'New property update',
+            message: 'A property has new activity',
+            type: 'INFO',
+            createdAt: new Date('2026-08-31T12:00:00.000Z'),
+          },
+        ]),
+      } as any,
     };
+    emailService = { sendEmail: jest.fn().mockResolvedValue(undefined) };
+    configService = { get: jest.fn().mockReturnValue('https://api.propchain.example/api') };
+
     service = new EmailDigestService(
       prisma as unknown as PrismaService,
-      { sendEmail: jest.fn() } as unknown as EmailService,
-      { get: jest.fn().mockReturnValue('') } as unknown as ConfigService,
+      emailService as unknown as EmailService,
+      configService as unknown as ConfigService,
     );
   });
 
@@ -29,4 +57,32 @@ describe('EmailDigestService', () => {
     );
     expect(result.userId).toBe('u1');
   });
-});
\ No newline at end of file
+
+  it('uses configured API_URL for digest unsubscribe links', async () => {
+    await service['sendDigestForUser'](
+      { id: 'u1', email: 'user@example.com', firstName: 'User' },
+      new Date('2026-08-30T12:00:00.000Z'),
+      'token-123',
+    );
+
+    expect(emailService.sendEmail).toHaveBeenCalledWith(
+      expect.objectContaining({
+        html: expect.stringContaining(
+          'https://api.propchain.example/api/email-digest/unsubscribe?token=token-123',
+        ),
+      }),
+    );
+  });
+
+  it('fails when API_URL is missing for digest unsubscribe links', async () => {
+    configService.get.mockReturnValue(undefined);
+
+    await expect(
+      service['sendDigestForUser'](
+        { id: 'u1', email: 'user@example.com', firstName: 'User' },
+        new Date('2026-08-30T12:00:00.000Z'),
+        'token-123',
+      ),
+    ).rejects.toThrow('API_URL environment variable is not set');
+  });
+});
diff --git a/src/email-digest/email-digest.service.ts b/src/email-digest/email-digest.service.ts
index beca649f..99c5cd9b 100644
--- a/src/email-digest/email-digest.service.ts
+++ b/src/email-digest/email-digest.service.ts
@@ -92,7 +92,13 @@ export class EmailDigestService {
 
     if (notifications.length === 0) return;
 
-    const apiUrl = this.configService.get<string>('API_URL', 'http://localhost:3000/api');
+    const apiUrl = this.configService.get<string>('API_URL');
+    if (!apiUrl) {
+      throw new Error(
+        'API_URL environment variable is not set. Cannot generate digest unsubscribe link.',
+      );
+    }
+
     const unsubscribeUrl = `${apiUrl}/email-digest/unsubscribe?token=${unsubscribeToken}`;
 
     const html = this.buildDigestHtml(user.firstName, notifications, unsubscribeUrl);