Switch email provider from Resend to Mailgun and add cron scheduler

- Replace resend package with mailgun.js and form-data
- Update email.ts to use Mailgun API with lazy client initialization
- Add instrumentation.ts to schedule cron jobs (notifications :00, Garmin :30)
- Update tests for Mailgun mock structure
- Update .env.example with MAILGUN_API_KEY and MAILGUN_DOMAIN

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

.env.example

@@ -11,8 +11,9 @@ NODE_ENV=development
 POCKETBASE_URL=http://localhost:8090
 NEXT_PUBLIC_POCKETBASE_URL=http://localhost:8090
 
-# Email (Resend)
+# Email (Mailgun)
-RESEND_API_KEY=re_xxxxxxxxxxxx
+MAILGUN_API_KEY=key-xxxxxxxxxxxx
+MAILGUN_DOMAIN=yourdomain.com
 EMAIL_FROM=phaseflow@yourdomain.com
 
 # Encryption (for Garmin tokens)

package.json

@@ -19,8 +19,10 @@
     "class-variance-authority": "^0.7.1",
     "clsx": "^2.1.1",
     "drizzle-orm": "^0.45.1",
+    "form-data": "^4.0.1",
     "ics": "^3.8.1",
     "lucide-react": "^0.562.0",
+    "mailgun.js": "^11.1.0",
     "next": "16.1.1",
     "node-cron": "^4.2.1",
     "oauth-1.0a": "^2.2.6",
@@ -29,7 +31,6 @@
     "prom-client": "^15.1.3",
     "react": "19.2.3",
     "react-dom": "19.2.3",
-    "resend": "^6.7.0",
     "sonner": "^2.0.7",
     "tailwind-merge": "^3.4.0",
     "zod": "^4.3.5"

pnpm-lock.yaml

@@ -17,12 +17,18 @@ importers:
       drizzle-orm:
         specifier: ^0.45.1
         version: 0.45.1(@opentelemetry/api@1.9.0)
+      form-data:
+        specifier: ^4.0.1
+        version: 4.0.5
       ics:
         specifier: ^3.8.1
         version: 3.8.1
       lucide-react:
         specifier: ^0.562.0
         version: 0.562.0(react@19.2.3)
+      mailgun.js:
+        specifier: ^11.1.0
+        version: 11.1.0
       next:
         specifier: 16.1.1
         version: 16.1.1(@babel/core@7.28.5)(@opentelemetry/api@1.9.0)(@playwright/test@1.56.1)(react-dom@19.2.3(react@19.2.3))(react@19.2.3)
@@ -47,9 +53,6 @@ importers:
       react-dom:
         specifier: 19.2.3
         version: 19.2.3(react@19.2.3)
-      resend:
-        specifier: ^6.7.0
-        version: 6.7.0
       sonner:
         specifier: ^2.0.7
         version: 2.0.7(react-dom@19.2.3(react@19.2.3))(react@19.2.3)
@@ -1119,9 +1122,6 @@ packages:
     cpu: [x64]
     os: [win32]
 
-  '@stablelib/base64@1.0.1':
-    resolution: {integrity: sha512-1bnPQqSxSuc3Ii6MhBysoWCg58j97aUjuCSZrGSmDxNqtytIi0k8utUenAwTZN4V5mXXYGsVUI9zeBqy+jBOSQ==}
-
   '@standard-schema/spec@1.1.0':
     resolution: {integrity: sha512-l2aFy5jALhniG5HgqrD6jXLi/rUWrKvqN/qJx6yoJsgKhblVd+iqqU4RCXavm/jPityDo5TCvKMnpjKnOriy0w==}
 
@@ -1337,10 +1337,19 @@ packages:
     resolution: {integrity: sha512-Izi8RQcffqCeNVgFigKli1ssklIbpHnCYc6AknXGYoB6grJqyeby7jv12JUQgmTAnIDnbck1uxksT4dzN3PWBA==}
     engines: {node: '>=12'}
 
+  asynckit@0.4.0:
+    resolution: {integrity: sha512-Oei9OH4tRh0YqU3GxhX79dM/mwVgvbZJaSNaRk+bshkj0S5cfHcgYakreBjrHwatXKbz+IoIdYLxrKim2MjW0Q==}
+
   atomic-sleep@1.0.0:
     resolution: {integrity: sha512-kNOjDqAh7px0XWNI+4QbzoiR/nTkHAWNud2uvnJquD1/x5a7EQZMJT0AczqK0Qn67oY/TTQ1LbUKajZpp3I9tQ==}
     engines: {node: '>=8.0.0'}
 
+  axios@1.13.2:
+    resolution: {integrity: sha512-VPk9ebNqPcy5lRGuSlKx752IlDatOjT9paPlm8A7yOuW2Fbvp4X3JznJtT4f0GzGLLiWE9W8onz51SqLYwzGaA==}
+
+  base-64@1.0.0:
+    resolution: {integrity: sha512-kwDPIFCGx0NZHog36dj+tHiwP4QMzsZ3AgMViUBKI0+V5n4U0ufTCUMhnQ04diaRI8EX/QcPfql7zlhZ7j4zgg==}
+
   baseline-browser-mapping@2.9.14:
     resolution: {integrity: sha512-B0xUquLkiGLgHhpPBqvl7GWegWBUNuujQ6kXd/r1U38ElPT6Ok8KZ8e+FpUGEc2ZoRQUzq/aUnaKFc/svWUGSg==}
     hasBin: true
@@ -1359,6 +1368,10 @@ packages:
   buffer-from@1.1.2:
     resolution: {integrity: sha512-E+XQCRwSbaaiChtv6k6Dwgc+bx+Bs6vuKJHHl5kox/BaKbhiXzqQOwK4cO22yElGp2OCmjwVhT3HmxgyPGnJfQ==}
 
+  call-bind-apply-helpers@1.0.2:
+    resolution: {integrity: sha512-Sp1ablJ0ivDkSzjcaJdxEunN5/XvksFJ2sMBFfq6x0ryhQV/2b/KwFe21cMpmHtPOSij8K99/wSfoEuTObmuMQ==}
+    engines: {node: '>= 0.4'}
+
   caniuse-lite@1.0.30001763:
     resolution: {integrity: sha512-mh/dGtq56uN98LlNX9qdbKnzINhX0QzhiWBFEkFfsFO4QyCvL8YegrJAazCwXIeqkIob8BlZPGM3xdnY+sgmvQ==}
 
@@ -1376,6 +1389,10 @@ packages:
     resolution: {integrity: sha512-eYm0QWBtUrBWZWG0d386OGAw16Z995PiOVo2B7bjWSbHedGl5e0ZWaq65kOGgUSNesEIDkB9ISbTg/JK9dhCZA==}
     engines: {node: '>=6'}
 
+  combined-stream@1.0.8:
+    resolution: {integrity: sha512-FQN4MRfuJeHf7cBbBMJFXhKSDq+2kAArBlmRBvcvFE5BB1HZKXtSFASDhdlz9zOYwxh8lDdnvmMOe/+5cdoEdg==}
+    engines: {node: '>= 0.8'}
+
   convert-source-map@2.0.0:
     resolution: {integrity: sha512-Kvp459HrV2FEJ1CAsi1Ku+MY3kasH19TFykTz2xWmMeq6bk2NU3XXvfJ+Q61m0xktWwt+1HSYf3JZsTms3aRJg==}
 
@@ -1409,6 +1426,10 @@ packages:
   decimal.js@10.6.0:
     resolution: {integrity: sha512-YpgQiITW3JXGntzdUmyUR1V812Hn8T1YVXhCu+wO3OpS4eU9l4YdD3qjyiKdV6mvV29zapkMeD390UVEf2lkUg==}
 
+  delayed-stream@1.0.0:
+    resolution: {integrity: sha512-ZySD7Nf91aLB0RxL4KGrKHBXl7Eds1DAmEdcoVawXnLD7SDhpNgtuII2aAkg7a7QS41jxPSZ17p4VdGnMHk3MQ==}
+    engines: {node: '>=0.4.0'}
+
   dequal@2.0.3:
     resolution: {integrity: sha512-0je+qPKHEMohvfRTCEo3CrPG6cAzAYgmzKyxRiYSSDkS6eGJdyVJm7WaYA5ECaAD9wLB2T4EEeymA5aFVcYXCA==}
     engines: {node: '>=6'}
@@ -1519,6 +1540,10 @@ packages:
       sqlite3:
         optional: true
 
+  dunder-proto@1.0.1:
+    resolution: {integrity: sha512-KIN/nDJBQRcXw0MLVhZE9iQHmG68qAVIBg9CqmUYjmQIhgij9U5MFvrqkUL5FbtyyzZuOeOt0zdeRe4UY7ct+A==}
+    engines: {node: '>= 0.4'}
+
   electron-to-chromium@1.5.267:
     resolution: {integrity: sha512-0Drusm6MVRXSOJpGbaSVgcQsuB4hEkMpHXaVstcPmhu5LIedxs1xNK/nIxmQIU/RPC0+1/o0AVZfBTkTNJOdUw==}
 
@@ -1530,9 +1555,25 @@ packages:
     resolution: {integrity: sha512-aN97NXWF6AWBTahfVOIrB/NShkzi5H7F9r1s9mD3cDj4Ko5f2qhhVoYMibXF7GlLveb/D2ioWay8lxI97Ven3g==}
     engines: {node: '>=0.12'}
 
+  es-define-property@1.0.1:
+    resolution: {integrity: sha512-e3nRfgfUZ4rNGL232gUgX06QNyyez04KdjFrF+LTRoOXmrOgFKDg4BCdsjW8EnT69eqdYGmRpJwiPVYNrCaW3g==}
+    engines: {node: '>= 0.4'}
+
+  es-errors@1.3.0:
+    resolution: {integrity: sha512-Zf5H2Kxt2xjTvbJvP2ZWLEICxA6j+hAmMzIlypy4xcBg1vKVnx89Wy0GbS+kf5cwCVFFzdCFh2XSCFNULS6csw==}
+    engines: {node: '>= 0.4'}
+
   es-module-lexer@1.7.0:
     resolution: {integrity: sha512-jEQoCwk8hyb2AZziIOLhDqpm5+2ww5uIE6lkO/6jcOCusfk6LhMHpXXfBLXTZ7Ydyt0j4VoUQv6uGNYbdW+kBA==}
 
+  es-object-atoms@1.1.1:
+    resolution: {integrity: sha512-FGgH2h8zKNim9ljj7dankFPcICIK9Cp5bm+c2gQSYePhpaG5+esrLODihIorn+Pe6FGJzWhXQotPv73jTaldXA==}
+    engines: {node: '>= 0.4'}
+
+  es-set-tostringtag@2.1.0:
+    resolution: {integrity: sha512-j6vWzfrGVfyXxge+O0x5sh6cvxAog0a/4Rdd2K36zCMV5eJ+/+tOAngRO8cODMNWbVRdVlmGZQL2YS3yR8bIUA==}
+    engines: {node: '>= 0.4'}
+
   esbuild-register@3.6.0:
     resolution: {integrity: sha512-H2/S7Pm8a9CL1uhp9OvjwrBh5Pvx0H8qVOxNu8Wed9Y7qv56MPtq+GGM8RJpq6glYJn9Wspr8uw7l55uyinNeg==}
     peerDependencies:
@@ -1564,9 +1605,6 @@ packages:
     resolution: {integrity: sha512-knvyeauYhqjOYvQ66MznSMs83wmHrCycNEN6Ao+2AeYEfxUIkuiVxdEa1qlGEPK+We3n0THiDciYSsCcgW/DoA==}
     engines: {node: '>=12.0.0'}
 
-  fast-sha256@1.3.0:
-    resolution: {integrity: sha512-n11RGP/lrWEFI/bWdygLxhI+pVeo1ZYIVwvvPkW7azl/rOy+F3HYRZ2K5zeE9mmkhQppyv9sQFx0JM9UabnpPQ==}
-
   fdir@6.5.0:
     resolution: {integrity: sha512-tIbYtZbucOs0BRGqPJkshJUYdL+SDH7dVM8gjy+ERp3WAUjLEFJE+02kanyHtwjWOnwrKYBiwAmM0p4kLJAnXg==}
     engines: {node: '>=12.0.0'}
@@ -1576,6 +1614,19 @@ packages:
       picomatch:
         optional: true
 
+  follow-redirects@1.15.11:
+    resolution: {integrity: sha512-deG2P0JfjrTxl50XGCDyfI97ZGVCxIpfKYmfyrQ54n5FO/0gfIES8C/Psl6kWVDolizcaaxZJnTS0QSMxvnsBQ==}
+    engines: {node: '>=4.0'}
+    peerDependencies:
+      debug: '*'
+    peerDependenciesMeta:
+      debug:
+        optional: true
+
+  form-data@4.0.5:
+    resolution: {integrity: sha512-8RipRLol37bNs2bhoV67fiTEvdTrbMUYcFTiy3+wuuOnUog2QBHCZWXDRijWQfAkhBj2Uf5UnVaiWwA5vdd82w==}
+    engines: {node: '>= 6'}
+
   fsevents@2.3.2:
     resolution: {integrity: sha512-xiqMQR4xAeHTuB9uWm+fFRcIOgKBMiOBP+eXiyT7jsgVCq1bkVygt00oASowB7EdtpOHaaPgKt812P9ab+DDKA==}
     engines: {node: ^8.16.0 || ^10.6.0 || >=11.0.0}
@@ -1586,16 +1637,43 @@ packages:
     engines: {node: ^8.16.0 || ^10.6.0 || >=11.0.0}
     os: [darwin]
 
+  function-bind@1.1.2:
+    resolution: {integrity: sha512-7XHNxH7qX9xG5mIwxkhumTox/MIRNcOgDrxWsMt2pAr23WHp6MrRlN7FBSFpCpr+oVO0F744iUgR82nJMfG2SA==}
+
   gensync@1.0.0-beta.2:
     resolution: {integrity: sha512-3hN7NaskYvMDLQY55gnW3NQ+mesEAepTqlg+VEbj7zzqEMBVNhzcGYYeqFo/TlYz6eQiFcp1HcsCZO+nGgS8zg==}
     engines: {node: '>=6.9.0'}
 
+  get-intrinsic@1.3.0:
+    resolution: {integrity: sha512-9fSjSaos/fRIVIp+xSJlE6lfwhES7LNtKaCBIamHsjr2na1BiABJPo0mOjjz8GJDURarmCPGqaiVg5mfjb98CQ==}
+    engines: {node: '>= 0.4'}
+
+  get-proto@1.0.1:
+    resolution: {integrity: sha512-sTSfBjoXBp89JvIKIefqw7U2CCebsc74kiY6awiGogKtoSGbgjYE/G/+l9sF3MWFPNc9IcoOC4ODfKHfxFmp0g==}
+    engines: {node: '>= 0.4'}
+
   get-tsconfig@4.13.0:
     resolution: {integrity: sha512-1VKTZJCwBrvbd+Wn3AOgQP/2Av+TfTCOlE4AcRJE72W1ksZXbAx8PPBR9RzgTeSPzlPMHrbANMH3LbltH73wxQ==}
 
+  gopd@1.2.0:
+    resolution: {integrity: sha512-ZUKRh6/kUFoAiTAtTYPZJ3hw9wNxx+BIBOijnlG9PnrJsCcSjs1wyyD6vJpaYtgnzDrKYRSqf3OO6Rfa93xsRg==}
+    engines: {node: '>= 0.4'}
+
   graceful-fs@4.2.11:
     resolution: {integrity: sha512-RbJ5/jmFcNNCcDV5o9eTnBLJ/HszWV0P73bc+Ff4nS/rJj+YaS6IGyiOL0VoBYX+l1Wrl3k63h/KrH+nhJ0XvQ==}
 
+  has-symbols@1.1.0:
+    resolution: {integrity: sha512-1cDNdwJ2Jaohmb3sg4OmKaMBwuC48sYni5HUw2DvsC8LjGTLK9h+eb1X6RyuOHe4hT0ULCW68iomhjUoKUqlPQ==}
+    engines: {node: '>= 0.4'}
+
+  has-tostringtag@1.0.2:
+    resolution: {integrity: sha512-NqADB8VjPFLM2V0VvHUewwwsw0ZWBaIdgo+ieHtK3hasLz4qeCRjYcqfB6AQrBggRKppKF8L52/VqdVsO47Dlw==}
+    engines: {node: '>= 0.4'}
+
+  hasown@2.0.2:
+    resolution: {integrity: sha512-0hJU9SCPvmMzIBdZFqNPXWa6dqh7WdH0cII9y+CyS8rG3nL48Bclra9HmKhVVUHyPWNH5Y7xDwAB7bfgSjkUMQ==}
+    engines: {node: '>= 0.4'}
+
   html-encoding-sniffer@6.0.0:
     resolution: {integrity: sha512-CV9TW3Y3f8/wT0BRFc1/KAVQ3TUHiXmaAb6VW9vtiMFf7SLoMd1PdAc4W3KFOFETBJUb90KatHqlsZMWV+R9Gg==}
     engines: {node: ^20.19.0 || ^22.12.0 || >=24.0.0}
@@ -1733,9 +1811,25 @@ packages:
   magic-string@0.30.21:
     resolution: {integrity: sha512-vd2F4YUyEXKGcLHoq+TEyCjxueSeHnFxyyjNp80yg0XV4vUhnDer/lvvlqM/arB5bXQN5K2/3oinyCRyx8T2CQ==}
 
+  mailgun.js@11.1.0:
+    resolution: {integrity: sha512-pXYcQT3nU32gMjUjZpl2FdQN4Vv2iobqYiXqyyevk0vXTKQj8Or0ifLXLNAGqMHnymTjV0OphBpurkchvHsRAg==}
+    engines: {node: '>=18.0.0'}
+
+  math-intrinsics@1.1.0:
+    resolution: {integrity: sha512-/IXtbwEk5HTPyEwyKX6hGkYXxM9nbj64B+ilVJnC/R6B0pH5G4V3b0pVbL7DBj4tkhBAppbQUlf6F6Xl9LHu1g==}
+    engines: {node: '>= 0.4'}
+
   mdn-data@2.12.2:
     resolution: {integrity: sha512-IEn+pegP1aManZuckezWCO+XZQDplx1366JoVhTpMpBB1sPey/SbveZQUosKiKiGYjg1wH4pMlNgXbCiYgihQA==}
 
+  mime-db@1.52.0:
+    resolution: {integrity: sha512-sPU4uV7dYlvtWJxwwxHD0PuihVNiE7TyAbQ5SWxDCB9mUYvOgroQOwYQQOKPJ8CIbE+1ETVlOoK1UC2nU3gYvg==}
+    engines: {node: '>= 0.6'}
+
+  mime-types@2.1.35:
+    resolution: {integrity: sha512-ZDY+bPm5zTTF+YpCrAU9nK0UgICYPT0QtT1NZWFv4s++TNkcgVaT0g6+4R2uI4MjQjzysHB1zxuWL50hzaeXiw==}
+    engines: {node: '>= 0.6'}
+
   min-indent@1.0.1:
     resolution: {integrity: sha512-I9jwMn07Sy/IwOj3zVkVik2JTvgpaykDZEigL6Rx6N9LbMywwUSMtxET+7lVoDLLd3O3IXwJwvuuns8UB/HeAg==}
     engines: {node: '>=4'}
@@ -1844,6 +1938,9 @@ packages:
   property-expr@2.0.6:
     resolution: {integrity: sha512-SVtmxhRE/CGkn3eZY1T6pC8Nln6Fr/lu1mKSgRud0eC73whjGfoAogbn78LkD8aFL0zz3bAFerKSnOl7NlErBA==}
 
+  proxy-from-env@1.1.0:
+    resolution: {integrity: sha512-D+zkORCbA9f1tdWRK0RaCR3GPv50cMxcrz4X8k5LTSUD1Dkw47mKJEZQNunItRTkWwgtaUSo1RVFRIG9ZXiFYg==}
+
   punycode@2.3.1:
     resolution: {integrity: sha512-vYt7UD1U9Wg6138shLtLOvdAu+8DsC/ilFtEVHcH+wydcSpNE20AfSOduf6MkRFahL5FY7X1oU7nKVZFtfq8Fg==}
     engines: {node: '>=6'}
@@ -1879,15 +1976,6 @@ packages:
     resolution: {integrity: sha512-Xf0nWe6RseziFMu+Ap9biiUbmplq6S9/p+7w7YXP/JBHhrUDDUhwa+vANyubuqfZWTveU//DYVGsDG7RKL/vEw==}
     engines: {node: '>=0.10.0'}
 
-  resend@6.7.0:
-    resolution: {integrity: sha512-2ZV0NDZsh4Gh+Nd1hvluZIitmGJ59O4+OxMufymG6Y8uz1Jgt2uS1seSENnkIUlmwg7/dwmfIJC9rAufByz7wA==}
-    engines: {node: '>=20'}
-    peerDependencies:
-      '@react-email/render': '*'
-    peerDependenciesMeta:
-      '@react-email/render':
-        optional: true
-
   resolve-pkg-maps@1.0.0:
     resolution: {integrity: sha512-seS2Tj26TBVOC2NIc2rOe2y2ZO7efxITtLZcGSOnHHNOQ7CkiUBfw0Iw2ck6xkIhPwLhKNLS8BO+hEpngQlqzw==}
 
@@ -1953,9 +2041,6 @@ packages:
   stackback@0.0.2:
     resolution: {integrity: sha512-1XMJE5fQo1jGH6Y/7ebnwPOBEkIEnT4QF32d5R1+VXdXveM0IBMJt8zfaxX1P3QhVwrYe+576+jkANtSS2mBbw==}
 
-  standardwebhooks@1.0.0:
-    resolution: {integrity: sha512-BbHGOQK9olHPMvQNHWul6MYlrRTAOKn03rOe4A8O3CLWhNf4YHBqq2HJKKC+sfqpxiBY52pNeesD6jIiLDz8jg==}
-
   std-env@3.10.0:
     resolution: {integrity: sha512-5GS12FdOZNliM5mAOxFRg7Ir0pWz8MdpYm6AY6VPkGpbA7ZzmbzNcBJQ0GPvvyWgcY7QAhCgf9Uy89I03faLkg==}
 
@@ -1976,9 +2061,6 @@ packages:
       babel-plugin-macros:
         optional: true
 
-  svix@1.84.1:
-    resolution: {integrity: sha512-K8DPPSZaW/XqXiz1kEyzSHYgmGLnhB43nQCMeKjWGCUpLIpAMMM8kx3rVVOSm6Bo6EHyK1RQLPT4R06skM/MlQ==}
-
   symbol-tree@3.2.4:
     resolution: {integrity: sha512-9QNk5KwDF+Bvz+PyObkmSYjI5ksVUYtjW7AU22r2NKcfLJcXp96hkDWU3+XndOsUb+AQ9QhfzfCT2O+CNWT5Tw==}
 
@@ -2059,9 +2141,8 @@ packages:
     peerDependencies:
       browserslist: '>= 4.21.0'
 
-  uuid@10.0.0:
+  url-join@4.0.1:
-    resolution: {integrity: sha512-8XkAphELsDnEGrDxUOHB3RGvXz6TeuYSGEZBOjtTtPm2lwhGBjLgOzLHB63IUWfBpNucQjND6d3AOudO+H3RWQ==}
+    resolution: {integrity: sha512-jk1+QP6ZJqyOiuEI9AEWQfju/nB2Pw466kbA0LEZljHwKeMgd9WrAEgEGxjPDD2+TNbbb37rTyhEfrCXfuKXnA==}
-    hasBin: true
 
   vite@7.3.1:
     resolution: {integrity: sha512-w+N7Hifpc3gRjZ63vYBXA56dvvRlNWRczTdmCBBa+CotUzAPf5b7YMdMR/8CQoeYE5LX3W4wj6RYTgonm1b9DA==}
@@ -2851,8 +2932,6 @@ snapshots:
   '@rollup/rollup-win32-x64-msvc@4.55.1':
     optional: true
 
-  '@stablelib/base64@1.0.1': {}
-
   '@standard-schema/spec@1.1.0': {}
 
   '@swc/helpers@0.5.15':
@@ -3071,8 +3150,20 @@ snapshots:
 
   assertion-error@2.0.1: {}
 
+  asynckit@0.4.0: {}
+
   atomic-sleep@1.0.0: {}
 
+  axios@1.13.2:
+    dependencies:
+      follow-redirects: 1.15.11
+      form-data: 4.0.5
+      proxy-from-env: 1.1.0
+    transitivePeerDependencies:
+      - debug
+
+  base-64@1.0.0: {}
+
   baseline-browser-mapping@2.9.14: {}
 
   bidi-js@1.0.3:
@@ -3091,6 +3182,11 @@ snapshots:
 
   buffer-from@1.1.2: {}
 
+  call-bind-apply-helpers@1.0.2:
+    dependencies:
+      es-errors: 1.3.0
+      function-bind: 1.1.2
+
   caniuse-lite@1.0.30001763: {}
 
   chai@6.2.2: {}
@@ -3103,6 +3199,10 @@ snapshots:
 
   clsx@2.1.1: {}
 
+  combined-stream@1.0.8:
+    dependencies:
+      delayed-stream: 1.0.0
+
   convert-source-map@2.0.0: {}
 
   css-tree@3.1.0:
@@ -3132,6 +3232,8 @@ snapshots:
 
   decimal.js@10.6.0: {}
 
+  delayed-stream@1.0.0: {}
+
   dequal@2.0.3: {}
 
   detect-libc@2.1.2: {}
@@ -3153,6 +3255,12 @@ snapshots:
     optionalDependencies:
       '@opentelemetry/api': 1.9.0
 
+  dunder-proto@1.0.1:
+    dependencies:
+      call-bind-apply-helpers: 1.0.2
+      es-errors: 1.3.0
+      gopd: 1.2.0
+
   electron-to-chromium@1.5.267: {}
 
   enhanced-resolve@5.18.4:
@@ -3162,8 +3270,23 @@ snapshots:
 
   entities@6.0.1: {}
 
+  es-define-property@1.0.1: {}
+
+  es-errors@1.3.0: {}
+
   es-module-lexer@1.7.0: {}
 
+  es-object-atoms@1.1.1:
+    dependencies:
+      es-errors: 1.3.0
+
+  es-set-tostringtag@2.1.0:
+    dependencies:
+      es-errors: 1.3.0
+      get-intrinsic: 1.3.0
+      has-tostringtag: 1.0.2
+      hasown: 2.0.2
+
   esbuild-register@3.6.0(esbuild@0.25.12):
     dependencies:
       debug: 4.4.3
@@ -3262,26 +3385,66 @@ snapshots:
 
   expect-type@1.3.0: {}
 
-  fast-sha256@1.3.0: {}
-
   fdir@6.5.0(picomatch@4.0.3):
     optionalDependencies:
       picomatch: 4.0.3
 
+  follow-redirects@1.15.11: {}
+
+  form-data@4.0.5:
+    dependencies:
+      asynckit: 0.4.0
+      combined-stream: 1.0.8
+      es-set-tostringtag: 2.1.0
+      hasown: 2.0.2
+      mime-types: 2.1.35
+
   fsevents@2.3.2:
     optional: true
 
   fsevents@2.3.3:
     optional: true
 
+  function-bind@1.1.2: {}
+
   gensync@1.0.0-beta.2: {}
 
+  get-intrinsic@1.3.0:
+    dependencies:
+      call-bind-apply-helpers: 1.0.2
+      es-define-property: 1.0.1
+      es-errors: 1.3.0
+      es-object-atoms: 1.1.1
+      function-bind: 1.1.2
+      get-proto: 1.0.1
+      gopd: 1.2.0
+      has-symbols: 1.1.0
+      hasown: 2.0.2
+      math-intrinsics: 1.1.0
+
+  get-proto@1.0.1:
+    dependencies:
+      dunder-proto: 1.0.1
+      es-object-atoms: 1.1.1
+
   get-tsconfig@4.13.0:
     dependencies:
       resolve-pkg-maps: 1.0.0
 
+  gopd@1.2.0: {}
+
   graceful-fs@4.2.11: {}
 
+  has-symbols@1.1.0: {}
+
+  has-tostringtag@1.0.2:
+    dependencies:
+      has-symbols: 1.1.0
+
+  hasown@2.0.2:
+    dependencies:
+      function-bind: 1.1.2
+
   html-encoding-sniffer@6.0.0:
     dependencies:
       '@exodus/bytes': 1.8.0
@@ -3413,8 +3576,24 @@ snapshots:
     dependencies:
       '@jridgewell/sourcemap-codec': 1.5.5
 
+  mailgun.js@11.1.0:
+    dependencies:
+      axios: 1.13.2
+      base-64: 1.0.0
+      url-join: 4.0.1
+    transitivePeerDependencies:
+      - debug
+
+  math-intrinsics@1.1.0: {}
+
   mdn-data@2.12.2: {}
 
+  mime-db@1.52.0: {}
+
+  mime-types@2.1.35:
+    dependencies:
+      mime-db: 1.52.0
+
   min-indent@1.0.1: {}
 
   ms@2.1.3: {}
@@ -3524,6 +3703,8 @@ snapshots:
 
   property-expr@2.0.6: {}
 
+  proxy-from-env@1.1.0: {}
+
   punycode@2.3.1: {}
 
   quick-format-unescaped@4.0.4: {}
@@ -3548,10 +3729,6 @@ snapshots:
 
   require-from-string@2.0.2: {}
 
-  resend@6.7.0:
-    dependencies:
-      svix: 1.84.1
-
   resolve-pkg-maps@1.0.0: {}
 
   rollup@4.55.1:
@@ -3656,11 +3833,6 @@ snapshots:
 
   stackback@0.0.2: {}
 
-  standardwebhooks@1.0.0:
-    dependencies:
-      '@stablelib/base64': 1.0.1
-      fast-sha256: 1.3.0
-
   std-env@3.10.0: {}
 
   strip-indent@3.0.0:
@@ -3674,11 +3846,6 @@ snapshots:
     optionalDependencies:
       '@babel/core': 7.28.5
 
-  svix@1.84.1:
-    dependencies:
-      standardwebhooks: 1.0.0
-      uuid: 10.0.0
-
   symbol-tree@3.2.4: {}
 
   tailwind-merge@3.4.0: {}
@@ -3740,7 +3907,7 @@ snapshots:
       escalade: 3.2.0
       picocolors: 1.1.1
 
-  uuid@10.0.0: {}
+  url-join@4.0.1: {}
 
   vite@7.3.1(@types/node@20.19.27)(jiti@2.6.1)(lightningcss@1.30.2):
     dependencies:

src/instrumentation.ts

@@ -0,0 +1,62 @@
+// ABOUTME: Next.js instrumentation file for server startup initialization.
+// ABOUTME: Schedules cron jobs for notifications and Garmin sync using node-cron.
+
+export async function register() {
+  // Only run on the server side
+  if (process.env.NEXT_RUNTIME === "nodejs") {
+    const cron = await import("node-cron");
+
+    const APP_URL = process.env.APP_URL || "http://localhost:3000";
+    const CRON_SECRET = process.env.CRON_SECRET;
+
+    // Log startup
+    console.log("[cron] Scheduler starting...");
+
+    if (!CRON_SECRET) {
+      console.warn(
+        "[cron] CRON_SECRET not set - cron jobs will fail authentication",
+      );
+    }
+
+    // Helper to call cron endpoints
+    async function triggerCronEndpoint(endpoint: string, name: string) {
+      try {
+        const response = await fetch(`${APP_URL}/api/cron/${endpoint}`, {
+          method: "POST",
+          headers: {
+            Authorization: `Bearer ${CRON_SECRET}`,
+            "Content-Type": "application/json",
+          },
+        });
+
+        if (!response.ok) {
+          const errorText = await response.text();
+          console.error(
+            `[cron] ${name} failed: ${response.status} ${errorText}`,
+          );
+        } else {
+          const result = await response.json();
+          console.log(`[cron] ${name} completed:`, result);
+        }
+      } catch (error) {
+        console.error(`[cron] ${name} error:`, error);
+      }
+    }
+
+    // Schedule notifications at the top of every hour
+    cron.default.schedule("0 * * * *", () => {
+      console.log("[cron] Triggering notifications...");
+      triggerCronEndpoint("notifications", "Notifications");
+    });
+
+    // Schedule Garmin sync at 30 minutes past every hour
+    cron.default.schedule("30 * * * *", () => {
+      console.log("[cron] Triggering Garmin sync...");
+      triggerCronEndpoint("garmin-sync", "Garmin sync");
+    });
+
+    console.log(
+      "[cron] Scheduler started - notifications at :00, Garmin sync at :30",
+    );
+  }
+}

src/lib/email.test.ts

@@ -1,20 +1,29 @@
 // ABOUTME: Unit tests for email sending utilities.
-// ABOUTME: Tests email composition, subject lines, and Resend integration.
+// ABOUTME: Tests email composition, subject lines, and Mailgun integration.
 import { afterEach, describe, expect, it, vi } from "vitest";
 
-const { mockSend, mockLoggerInfo, mockLoggerError } = vi.hoisted(() => ({
+const { mockCreate, mockLoggerInfo, mockLoggerError } = vi.hoisted(() => ({
-  mockSend: vi.fn().mockResolvedValue({ id: "mock-email-id" }),
+  mockCreate: vi.fn().mockResolvedValue({ id: "mock-email-id" }),
   mockLoggerInfo: vi.fn(),
   mockLoggerError: vi.fn(),
 }));
 
-// Mock the resend module before importing email utilities
+// Mock the mailgun.js module before importing email utilities
-vi.mock("resend", () => ({
+vi.mock("mailgun.js", () => ({
-  Resend: class MockResend {
+  default: class MockMailgun {
-    emails = { send: mockSend };
+    client() {
+      return {
+        messages: { create: mockCreate },
+      };
+    }
   },
 }));
 
+// Mock form-data (required by mailgun.js)
+vi.mock("form-data", () => ({
+  default: class MockFormData {},
+}));
+
 // Mock the logger
 vi.mock("@/lib/logger", () => ({
   logger: {
@@ -57,7 +66,9 @@ describe("sendDailyEmail", () => {
 
   it("sends email with correct subject line per spec", async () => {
     await sendDailyEmail(sampleData);
-    expect(mockSend).toHaveBeenCalledWith(
+    // Mailgun create takes (domain, messageData) - check second param
+    expect(mockCreate).toHaveBeenCalledWith(
+      expect.any(String),
       expect.objectContaining({
         subject: "PhaseFlow: 💪 TRAIN - Day 15 (OVULATION)",
       }),
@@ -66,13 +77,13 @@ describe("sendDailyEmail", () => {
 
   it("includes cycle day and phase in email body", async () => {
     await sendDailyEmail(sampleData);
-    const call = mockSend.mock.calls[0][0];
+    const call = mockCreate.mock.calls[0][1];
     expect(call.text).toContain("📅 CYCLE DAY: 15 (OVULATION)");
   });
 
   it("includes decision icon and reason", async () => {
     await sendDailyEmail(sampleData);
-    const call = mockSend.mock.calls[0][0];
+    const call = mockCreate.mock.calls[0][1];
     expect(call.text).toContain(
       "💪 Body battery high, HRV balanced - great day for training!",
     );
@@ -80,7 +91,7 @@ describe("sendDailyEmail", () => {
 
   it("includes biometric data in email body", async () => {
     await sendDailyEmail(sampleData);
-    const call = mockSend.mock.calls[0][0];
+    const call = mockCreate.mock.calls[0][1];
     expect(call.text).toContain("Body Battery Now: 85");
     expect(call.text).toContain("Yesterday's Low: 45");
     expect(call.text).toContain("HRV Status: Balanced");
@@ -90,7 +101,7 @@ describe("sendDailyEmail", () => {
 
   it("includes nutrition guidance in email body", async () => {
     await sendDailyEmail(sampleData);
-    const call = mockSend.mock.calls[0][0];
+    const call = mockCreate.mock.calls[0][1];
     expect(call.text).toContain(
       "🌱 SEEDS: Sesame (1-2 tbsp) + Sunflower (1-2 tbsp)",
     );
@@ -107,30 +118,32 @@ describe("sendDailyEmail", () => {
       bodyBatteryYesterdayLow: null,
     };
     await sendDailyEmail(dataWithNulls);
-    const call = mockSend.mock.calls[0][0];
+    const call = mockCreate.mock.calls[0][1];
     expect(call.text).toContain("Body Battery Now: N/A");
     expect(call.text).toContain("Yesterday's Low: N/A");
   });
 
   it("sends email to correct recipient", async () => {
     await sendDailyEmail(sampleData);
-    expect(mockSend).toHaveBeenCalledWith(
+    // Mailgun uses an array for recipients
+    expect(mockCreate).toHaveBeenCalledWith(
+      expect.any(String),
       expect.objectContaining({
-        to: "user@example.com",
+        to: ["user@example.com"],
       }),
     );
   });
 
   it("includes auto-generated footer", async () => {
     await sendDailyEmail(sampleData);
-    const call = mockSend.mock.calls[0][0];
+    const call = mockCreate.mock.calls[0][1];
     expect(call.text).toContain("Auto-generated by PhaseFlow");
   });
 
   it("includes seed switch alert on day 15", async () => {
     // sampleData already has cycleDay: 15
     await sendDailyEmail(sampleData);
-    const call = mockSend.mock.calls[0][0];
+    const call = mockCreate.mock.calls[0][1];
     expect(call.text).toContain("🌱 SWITCH TODAY! Start Sesame + Sunflower");
   });
 
@@ -140,7 +153,7 @@ describe("sendDailyEmail", () => {
       cycleDay: 10,
     };
     await sendDailyEmail(day10Data);
-    const call = mockSend.mock.calls[0][0];
+    const call = mockCreate.mock.calls[0][1];
     expect(call.text).not.toContain("SWITCH TODAY");
   });
 });
@@ -156,7 +169,8 @@ describe("sendPeriodConfirmationEmail", () => {
       new Date("2025-01-15"),
       31,
     );
-    expect(mockSend).toHaveBeenCalledWith(
+    expect(mockCreate).toHaveBeenCalledWith(
+      expect.any(String),
       expect.objectContaining({
         subject: "🔵 Period Tracking Updated",
       }),
@@ -169,7 +183,7 @@ describe("sendPeriodConfirmationEmail", () => {
       new Date("2025-01-15"),
       31,
     );
-    const call = mockSend.mock.calls[0][0];
+    const call = mockCreate.mock.calls[0][1];
     // Date formatting depends on locale, so check for key parts
     expect(call.text).toContain("Your cycle has been reset");
     expect(call.text).toContain("Last period:");
@@ -181,7 +195,7 @@ describe("sendPeriodConfirmationEmail", () => {
       new Date("2025-01-15"),
       28,
     );
-    const call = mockSend.mock.calls[0][0];
+    const call = mockCreate.mock.calls[0][1];
     expect(call.text).toContain("Phase calendar updated for next 28 days");
   });
 
@@ -191,9 +205,10 @@ describe("sendPeriodConfirmationEmail", () => {
       new Date("2025-01-15"),
       31,
     );
-    expect(mockSend).toHaveBeenCalledWith(
+    expect(mockCreate).toHaveBeenCalledWith(
+      expect.any(String),
       expect.objectContaining({
-        to: "test@example.com",
+        to: ["test@example.com"],
       }),
     );
   });
@@ -204,7 +219,7 @@ describe("sendPeriodConfirmationEmail", () => {
       new Date("2025-01-15"),
       31,
     );
-    const call = mockSend.mock.calls[0][0];
+    const call = mockCreate.mock.calls[0][1];
     expect(call.text).toContain("Auto-generated by PhaseFlow");
   });
 
@@ -214,7 +229,7 @@ describe("sendPeriodConfirmationEmail", () => {
       new Date("2025-01-15"),
       31,
     );
-    const call = mockSend.mock.calls[0][0];
+    const call = mockCreate.mock.calls[0][1];
     expect(call.text).toContain(
       "Your calendar will update automatically within 24 hours",
     );
@@ -229,7 +244,8 @@ describe("sendTokenExpirationWarning", () => {
   describe("14-day warning", () => {
     it("sends email with correct subject for 14-day warning", async () => {
       await sendTokenExpirationWarning("user@example.com", 14);
-      expect(mockSend).toHaveBeenCalledWith(
+      expect(mockCreate).toHaveBeenCalledWith(
+        expect.any(String),
         expect.objectContaining({
           subject: "⚠️ PhaseFlow: Garmin tokens expire in 14 days",
         }),
@@ -238,29 +254,30 @@ describe("sendTokenExpirationWarning", () => {
 
     it("sends to correct recipient", async () => {
       await sendTokenExpirationWarning("user@example.com", 14);
-      expect(mockSend).toHaveBeenCalledWith(
+      expect(mockCreate).toHaveBeenCalledWith(
+        expect.any(String),
         expect.objectContaining({
-          to: "user@example.com",
+          to: ["user@example.com"],
         }),
       );
     });
 
     it("includes days until expiry in body", async () => {
       await sendTokenExpirationWarning("user@example.com", 14);
-      const call = mockSend.mock.calls[0][0];
+      const call = mockCreate.mock.calls[0][1];
       expect(call.text).toContain("14 days");
     });
 
     it("includes instructions to refresh tokens", async () => {
       await sendTokenExpirationWarning("user@example.com", 14);
-      const call = mockSend.mock.calls[0][0];
+      const call = mockCreate.mock.calls[0][1];
       expect(call.text).toContain("Settings");
       expect(call.text).toContain("Garmin");
     });
 
     it("includes auto-generated footer", async () => {
       await sendTokenExpirationWarning("user@example.com", 14);
-      const call = mockSend.mock.calls[0][0];
+      const call = mockCreate.mock.calls[0][1];
       expect(call.text).toContain("Auto-generated by PhaseFlow");
     });
   });
@@ -268,7 +285,8 @@ describe("sendTokenExpirationWarning", () => {
   describe("7-day warning", () => {
     it("sends email with urgent subject for 7-day warning", async () => {
       await sendTokenExpirationWarning("user@example.com", 7);
-      expect(mockSend).toHaveBeenCalledWith(
+      expect(mockCreate).toHaveBeenCalledWith(
+        expect.any(String),
         expect.objectContaining({
           subject:
             "🚨 PhaseFlow: Garmin tokens expire in 7 days - action required",
@@ -278,28 +296,29 @@ describe("sendTokenExpirationWarning", () => {
 
     it("sends to correct recipient", async () => {
       await sendTokenExpirationWarning("user@example.com", 7);
-      expect(mockSend).toHaveBeenCalledWith(
+      expect(mockCreate).toHaveBeenCalledWith(
+        expect.any(String),
         expect.objectContaining({
-          to: "user@example.com",
+          to: ["user@example.com"],
         }),
       );
     });
 
     it("includes days until expiry in body", async () => {
       await sendTokenExpirationWarning("user@example.com", 7);
-      const call = mockSend.mock.calls[0][0];
+      const call = mockCreate.mock.calls[0][1];
       expect(call.text).toContain("7 days");
     });
 
     it("uses more urgent tone than 14-day warning", async () => {
       await sendTokenExpirationWarning("user@example.com", 7);
-      const call = mockSend.mock.calls[0][0];
+      const call = mockCreate.mock.calls[0][1];
       expect(call.text).toContain("urgent");
     });
 
     it("includes auto-generated footer", async () => {
       await sendTokenExpirationWarning("user@example.com", 7);
-      const call = mockSend.mock.calls[0][0];
+      const call = mockCreate.mock.calls[0][1];
       expect(call.text).toContain("Auto-generated by PhaseFlow");
     });
   });
@@ -344,12 +363,12 @@ describe("email structured logging", () => {
     });
 
     it("logs email failed with error level on failure", async () => {
-      const error = new Error("Resend API failed");
+      const error = new Error("Mailgun API failed");
-      mockSend.mockRejectedValueOnce(error);
+      mockCreate.mockRejectedValueOnce(error);
 
       await expect(
         sendDailyEmail(sampleDailyEmailData, "user-123"),
-      ).rejects.toThrow("Resend API failed");
+      ).rejects.toThrow("Mailgun API failed");
 
       expect(mockLoggerError).toHaveBeenCalledWith(
         expect.objectContaining({
@@ -381,8 +400,8 @@ describe("email structured logging", () => {
     });
 
     it("logs email failed with error level on failure", async () => {
-      const error = new Error("Resend API failed");
+      const error = new Error("Mailgun API failed");
-      mockSend.mockRejectedValueOnce(error);
+      mockCreate.mockRejectedValueOnce(error);
 
       await expect(
         sendPeriodConfirmationEmail(
@@ -391,7 +410,7 @@ describe("email structured logging", () => {
           31,
           "user-456",
         ),
-      ).rejects.toThrow("Resend API failed");
+      ).rejects.toThrow("Mailgun API failed");
 
       expect(mockLoggerError).toHaveBeenCalledWith(
         expect.objectContaining({
@@ -418,12 +437,12 @@ describe("email structured logging", () => {
     });
 
     it("logs email failed with error level on failure", async () => {
-      const error = new Error("Resend API failed");
+      const error = new Error("Mailgun API failed");
-      mockSend.mockRejectedValueOnce(error);
+      mockCreate.mockRejectedValueOnce(error);
 
       await expect(
         sendTokenExpirationWarning("user@example.com", 14, "user-789"),
-      ).rejects.toThrow("Resend API failed");
+      ).rejects.toThrow("Mailgun API failed");
 
       expect(mockLoggerError).toHaveBeenCalledWith(
         expect.objectContaining({

src/lib/email.ts

@@ -1,13 +1,28 @@
-// ABOUTME: Email sending utilities using Resend.
+// ABOUTME: Email sending utilities using Mailgun.
 // ABOUTME: Sends daily training notifications and period confirmation emails.
-import { Resend } from "resend";
+import FormData from "form-data";
+import Mailgun from "mailgun.js";
+import type { IMailgunClient } from "mailgun.js/Interfaces";
 
 import { logger } from "@/lib/logger";
 import { emailSentTotal } from "@/lib/metrics";
 import { getSeedSwitchAlert } from "@/lib/nutrition";
 
-const resend = new Resend(process.env.RESEND_API_KEY);
+// Lazy-initialize Mailgun client to avoid build-time errors when env vars aren't set
+let mg: IMailgunClient | null = null;
 
+function getMailgunClient(): IMailgunClient {
+  if (!mg) {
+    const mailgun = new Mailgun(FormData);
+    mg = mailgun.client({
+      username: "api",
+      key: process.env.MAILGUN_API_KEY || "",
+    });
+  }
+  return mg;
+}
+
+const MAILGUN_DOMAIN = process.env.MAILGUN_DOMAIN || "paler.net";
 const EMAIL_FROM = process.env.EMAIL_FROM || "phaseflow@example.com";
 
 export interface DailyEmailData {
@@ -64,9 +79,9 @@ ${data.decision.icon} ${data.decision.reason}
 Auto-generated by PhaseFlow`;
 
   try {
-    await resend.emails.send({
+    await getMailgunClient().messages.create(MAILGUN_DOMAIN, {
       from: EMAIL_FROM,
-      to: data.to,
+      to: [data.to],
       subject,
       text: body,
     });
@@ -96,9 +111,9 @@ Your calendar will update automatically within 24 hours.
 Auto-generated by PhaseFlow`;
 
   try {
-    await resend.emails.send({
+    await getMailgunClient().messages.create(MAILGUN_DOMAIN, {
       from: EMAIL_FROM,
-      to,
+      to: [to],
       subject,
       text: body,
     });
@@ -141,9 +156,9 @@ This will ensure your training recommendations continue to use fresh Garmin data
 Auto-generated by PhaseFlow`;
 
   try {
-    await resend.emails.send({
+    await getMailgunClient().messages.create(MAILGUN_DOMAIN, {
       from: EMAIL_FROM,
-      to,
+      to: [to],
       subject,
       text: body,
     });