feat: add authenticated Resend subscriber sync

Author: thedaviddias

.vercelignore

@@ -0,0 +1,38 @@
+# Dependencies
+node_modules
+.pnp
+.pnp.js
+
+# Local build and cache output
+.next
+**/.next
+.turbo
+**/.turbo
+.content-collections
+**/.content-collections
+coverage
+**/coverage
+
+# Test artifacts
+test-results
+**/test-results
+playwright-report
+**/playwright-report
+blob-report
+**/blob-report
+*.trace.zip
+
+# Local environment and tooling state
+.env
+.env.*
+.vercel
+.DS_Store
+*.pem
+*.tsbuildinfo
+next-env.d.ts
+
+# Local/generated agent artifacts
+.artifacts
+.claude
+.agents/skills
+.cursor

apps/web/app/api/subscribe/me/__tests__/route.test.ts

@@ -0,0 +1,112 @@
+/**
+ * @jest-environment node
+ */
+
+const mockGetSession = jest.fn()
+const mockCreate = jest.fn()
+const originalApiKey = process.env.RESEND_API_KEY
+
+process.env.RESEND_API_KEY = 're_test_key'
+
+jest.mock('@repo/auth/auth', () => ({
+  auth: {
+    api: {
+      getSession: mockGetSession
+    }
+  }
+}))
+
+jest.mock('resend', () => ({
+  Resend: jest.fn().mockImplementation(() => ({
+    contacts: {
+      create: mockCreate
+    }
+  }))
+}))
+
+jest.mock('next/headers', () => ({
+  headers: jest.fn()
+}))
+
+jest.mock('@/lib/telemetry-server', () => ({
+  captureServerException: jest.fn()
+}))
+
+const { headers } = require('next/headers')
+const { POST } = require('../route')
+
+describe('subscribe me route', () => {
+  afterAll(() => {
+    if (originalApiKey === undefined) {
+      delete process.env.RESEND_API_KEY
+    } else {
+      process.env.RESEND_API_KEY = originalApiKey
+    }
+  })
+
+  beforeEach(() => {
+    jest.clearAllMocks()
+    headers.mockResolvedValue(new Headers())
+  })
+
+  it('requires an authenticated user', async () => {
+    mockGetSession.mockResolvedValue(null)
+
+    const response = await POST()
+
+    expect(response.status).toBe(401)
+    await expect(response.json()).resolves.toEqual({ error: 'Unauthorized' })
+  })
+
+  it('syncs the current signed-in user email to Resend', async () => {
+    mockGetSession.mockResolvedValue({
+      user: {
+        email: ' test@example.com ',
+        id: 'user-1'
+      }
+    })
+    mockCreate.mockResolvedValue({ data: { id: 'contact-1' }, error: null })
+
+    const response = await POST()
+
+    expect(mockCreate).toHaveBeenCalledWith(
+      expect.objectContaining({
+        email: 'test@example.com',
+        properties: expect.objectContaining({
+          product: 'newsletter',
+          user_type: 'subscriber'
+        })
+      })
+    )
+    expect(response.status).toBe(201)
+    await expect(response.json()).resolves.toEqual({
+      id: 'contact-1',
+      status: 'created',
+      success: true
+    })
+  })
+
+  it('returns success when the current user already exists in Resend', async () => {
+    mockGetSession.mockResolvedValue({
+      user: {
+        email: 'test@example.com',
+        id: 'user-1'
+      }
+    })
+    mockCreate.mockResolvedValue({
+      data: null,
+      error: {
+        message: 'Contact already exists',
+        name: 'validation_error'
+      }
+    })
+
+    const response = await POST()
+
+    expect(response.status).toBe(200)
+    await expect(response.json()).resolves.toEqual({
+      status: 'already_exists',
+      success: true
+    })
+  })
+})

apps/web/app/api/subscribe/me/route.ts

@@ -0,0 +1,32 @@
+import { auth } from '@repo/auth/auth'
+import { addSubscriberContact } from '@repo/emails/server'
+import { headers } from 'next/headers'
+import { NextResponse } from 'next/server'
+import { captureServerException } from '@/lib/telemetry-server'
+
+/**
+ * Add the current signed-in user's email to the mailing list audience.
+ */
+export async function POST() {
+  try {
+    const session = await auth.api.getSession({ headers: await headers() })
+    if (!session?.user?.id) {
+      return NextResponse.json({ error: 'Unauthorized' }, { status: 401 })
+    }
+
+    const email = session.user.email?.trim()
+    if (!email) {
+      return NextResponse.json({ error: 'Current user has no email' }, { status: 400 })
+    }
+
+    const result = await addSubscriberContact(email)
+    if (!result.success) {
+      return NextResponse.json({ error: result.error }, { status: result.statusCode })
+    }
+
+    return NextResponse.json(result, { status: result.status === 'created' ? 201 : 200 })
+  } catch (error) {
+    captureServerException(error, { route: '/api/subscribe/me' })
+    return NextResponse.json({ error: 'Failed to add contact' }, { status: 500 })
+  }
+}

apps/web/app/api/subscribe/route.ts

@@ -1,4 +1,4 @@
-import { createResendContactPayload, getResendClient } from '@repo/emails/server'
+import { addSubscriberContact } from '@repo/emails/server'
 import { NextResponse } from 'next/server'
 import { captureServerException } from '@/lib/telemetry-server'
 
@@ -32,23 +32,12 @@ export async function POST(request: Request) {
       return NextResponse.json({ error: 'Missing email' }, { status: 400 })
     }
 
-    const resend = getResendClient()
-    if (!resend) {
-      return NextResponse.json({ error: 'Resend not configured' }, { status: 503 })
+    const result = await addSubscriberContact(email)
+    if (!result.success) {
+      return NextResponse.json({ error: result.error }, { status: result.statusCode })
     }
 
-    const { error } = await resend.contacts.create(
-      createResendContactPayload(email, 'subscriber', process.env.RESEND_AUDIENCE_ID)
-    )
-
-    if (error) {
-      const message = error.message ?? 'Failed to add contact'
-      const statusCode =
-        error.name === 'validation_error' || message.toLowerCase().includes('already') ? 400 : 500
-      return NextResponse.json({ error: message }, { status: statusCode })
-    }
-
-    return NextResponse.json({ success: true }, { status: 201 })
+    return NextResponse.json(result, { status: result.status === 'created' ? 201 : 200 })
   } catch (error) {
     captureServerException(error, { route: '/api/subscribe' })
     return NextResponse.json({ error: 'Failed to add contact' }, { status: 500 })

apps/web/jest.config.cjs

@@ -23,6 +23,7 @@ const customJestConfig = {
     '^@repo/design-system/custom/(.*)$': '<rootDir>/../../packages/design-system/src/custom/$1.tsx',
     '^@repo/design-system/ui/(.*)$': '<rootDir>/../../packages/design-system/src/ui/$1.tsx',
     '^@repo/design-system/icons$': '<rootDir>/../../packages/design-system/src/icons.ts',
+    '^@repo/emails/server$': '<rootDir>/../../packages/emails/src/server.ts',
     '^.*custom/(.*)/src$': '<rootDir>/../../packages/design-system/src/custom/$1.tsx',
     '^.*packages/design-system/custom/(.*)/src$':
       '<rootDir>/../../packages/design-system/src/custom/$1.tsx',

apps/web/tsconfig.json

@@ -13,7 +13,9 @@
       "content-collections": ["./.content-collections/generated"],
       "@repo/*": ["../../packages/*/src"],
       "@repo/auth": ["../../packages/auth/src/auth.ts"],
-      "@repo/auth/*": ["../../packages/auth/src/*"]
+      "@repo/auth/*": ["../../packages/auth/src/*"],
+      "@repo/emails": ["../../packages/emails/src/index.ts"],
+      "@repo/emails/server": ["../../packages/emails/src/server.ts"]
     }
   },
   "include": [

package.json

@@ -25,7 +25,7 @@
     "test:guide-structure": "node --import tsx --test scripts/guide-structure/__tests__/*.test.ts scripts/validate/__tests__/validate-guides.test.ts",
     "typecheck": "turbo typecheck",
     "clean": "turbo clean && rm -rf node_modules",
-    "prepare": "lefthook install",
+    "prepare": "node scripts/setup/install-lefthook.mjs",
     "lefthook:run": "lefthook run pre-commit",
     "qmd:setup": "./scripts/setup-qmd.sh",
     "qmd:embed": "./scripts/setup-qmd.sh --embed",

packages/emails/src/__tests__/server.test.ts

@@ -13,6 +13,7 @@ describe('@repo/emails/server', () => {
     } else {
       process.env.RESEND_TOPIC_ID = originalTopicId
     }
+    jest.dontMock('resend')
     jest.resetModules()
   })
 
@@ -77,4 +78,60 @@ describe('@repo/emails/server', () => {
       topics: [{ id: 'cdb0d440-4825-412a-8152-29681e8155b7', subscription: 'opt_in' }]
     })
   })
+
+  it('adds subscriber contacts through Resend', async () => {
+    process.env.RESEND_API_KEY = 're_test_key'
+    const mockCreate = jest.fn().mockResolvedValue({ data: { id: 'contact-1' }, error: null })
+    jest.doMock('resend', () => ({
+      Resend: jest.fn().mockImplementation(() => ({
+        contacts: {
+          create: mockCreate
+        }
+      }))
+    }))
+
+    const { addSubscriberContact } = await import('../server')
+
+    await expect(addSubscriberContact(' test@example.com ', ' segment-1 ')).resolves.toEqual({
+      id: 'contact-1',
+      status: 'created',
+      success: true
+    })
+    expect(mockCreate).toHaveBeenCalledWith({
+      email: 'test@example.com',
+      properties: {
+        product: 'newsletter',
+        user_type: 'subscriber',
+        language: 'en',
+        source_domain: 'frontendchecklist.io',
+        brand: 'frontendchecklist'
+      },
+      segments: [{ id: 'segment-1' }],
+      topics: [{ id: 'cdb0d440-4825-412a-8152-29681e8155b7', subscription: 'opt_in' }]
+    })
+  })
+
+  it('treats existing Resend contacts as a successful sync', async () => {
+    process.env.RESEND_API_KEY = 're_test_key'
+    jest.doMock('resend', () => ({
+      Resend: jest.fn().mockImplementation(() => ({
+        contacts: {
+          create: jest.fn().mockResolvedValue({
+            data: null,
+            error: {
+              message: 'Contact already exists',
+              name: 'validation_error'
+            }
+          })
+        }
+      }))
+    }))
+
+    const { addSubscriberContact } = await import('../server')
+
+    await expect(addSubscriberContact('test@example.com')).resolves.toEqual({
+      status: 'already_exists',
+      success: true
+    })
+  })
 })