diff --git a/README.md b/README.md
index 51c9fa7..3af5090 100644
--- a/README.md
+++ b/README.md
@@ -130,8 +130,9 @@ docker run -d \
 ## Tests
 
 ```sh
-pnpm test          # Run integration tests
-pnpm test:server   # Start server for manual testing
+pnpm test:unit       # Run unit tests (vitest)
+pnpm test            # Run integration tests (bash E2E)
+pnpm test:server     # Start server for manual testing
 ```
 
 ## Forked from Anchor
diff --git a/package.json b/package.json
index 9ac4de2..306a4b7 100644
--- a/package.json
+++ b/package.json
@@ -11,6 +11,7 @@
     "preview:digest": "node script/render-preview.mjs",
     "run-alert": "node dist/run.js",
     "test": "bash test/integration.sh",
+    "test:unit": "vitest run",
     "test:server": "bash test/integration.sh --server-only"
   },
   "devDependencies": {
@@ -29,7 +30,8 @@
     "globals": "^15.15.0",
     "onchange": "^7.1.0",
     "prettier": "^3.6.2",
-    "typescript": "^5.9.2"
+    "typescript": "^5.9.2",
+    "vitest": "^5.0.0"
   },
   "dependencies": {
     "@types/node": "^22.18.1",
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 15e0f81..f444b05 100644
Binary files a/pnpm-lock.yaml and b/pnpm-lock.yaml differ
diff --git a/script/checks b/script/checks
index 310e1d1..287929d 100755
--- a/script/checks
+++ b/script/checks
@@ -1,6 +1,7 @@
 #!/usr/bin/env bash
 set -euo pipefail
 
-# mailship CI checks — type-check + lint + build
+# mailship CI checks — type-check + lint + build + unit tests
 pnpm run check
-pnpm run build
\ No newline at end of file
+pnpm run build
+pnpm test:unit
\ No newline at end of file
diff --git a/test/digest-template.test.js b/test/digest-template.test.js
deleted file mode 100644
index 47de77f..0000000
--- a/test/digest-template.test.js
+++ /dev/null
@@ -1,74 +0,0 @@
-#!/usr/bin/env node
-// FAILING test: digest.mjml hardcodes #7161FF instead of using {{brandAccent}}
-//
-// The bug: in src/emails/digest.mjml line 8 and line 22, the CSS for
-// .event-item border-left and .footer a color hardcode #7161FF even though
-// {{brandAccent}} is passed into the template by mailer.ts and used
-// elsewhere (lines 15, 34). When BRAND_ACCENT is customized, the event-item
-// border and footer links stay the default purple.
-//
-// The fix: replace both hardcoded #7161FF values with {{brandAccent}}.
-
-import { readFileSync } from 'fs';
-import { fileURLToPath } from 'url';
-import { dirname, join } from 'path';
-
-const __dirname = dirname(fileURLToPath(import.meta.url));
-const templatePath = join(__dirname, '..', 'src', 'emails', 'digest.mjml');
-
-let passed = 0;
-let failed = 0;
-
-function assert(label, ok, detail) {
-  if (ok) {
-    console.log(`  ✓ ${label}`);
-    passed++;
-  } else {
-    console.log(`  ✗ ${label} — ${detail || ''}`);
-    failed++;
-  }
-}
-
-// Read the MJML template
-const source = readFileSync(templatePath, 'utf8');
-const lines = source.split('\n');
-
-console.log('1. No hardcoded #7161FF in .event-item or .footer a CSS');
-
-// Check .event-item border-left doesn't have #7161FF
-const eventItemLineIdx = lines.findIndex(l => l.includes('.event-item'));
-const hasEventItemHardcoded = lines.some(l => l.includes('.event-item') && l.includes('#7161FF'));
-assert(
-  '.event-item border-left does NOT hardcode #7161FF',
-  !hasEventItemHardcoded,
-  hasEventItemHardcoded ? `Line ${eventItemLineIdx + 1} still has #7161FF: "${lines[eventItemLineIdx].trim()}"` : ''
-);
-
-// Check .footer a color doesn't have #7161FF
-const footerAIdx = lines.findIndex(l => l.includes('.footer a'));
-const hasFooterHardcoded = lines.some(l => l.includes('.footer a') && l.includes('#7161FF'));
-assert(
-  '.footer a color does NOT hardcode #7161FF',
-  !hasFooterHardcoded,
-  hasFooterHardcoded ? `Line ${footerAIdx + 1} still has #7161FF: "${lines[footerAIdx].trim()}"` : ''
-);
-
-// Check .event-item border-left uses {{brandAccent}}
-const eventItemLine = lines[eventItemLineIdx];
-assert(
-  '.event-item border-left uses {{brandAccent}}',
-  eventItemLine && eventItemLine.includes('{{brandAccent}}'),
-  eventItemLine ? `Line ${eventItemLineIdx + 1}: "${eventItemLine.trim()}"` : '.event-item line not found'
-);
-
-// Check .footer a color uses {{brandAccent}}
-const footerALine = lines[footerAIdx];
-assert(
-  '.footer a color uses {{brandAccent}}',
-  footerALine && footerALine.includes('{{brandAccent}}'),
-  footerALine ? `Line ${footerAIdx + 1}: "${footerALine.trim()}"` : '.footer a line not found'
-);
-
-console.log('');
-console.log(`Results: ${passed} passed, ${failed} failed`);
-process.exit(failed > 0 ? 1 : 0);
\ No newline at end of file
diff --git a/test/digest-template.test.ts b/test/digest-template.test.ts
new file mode 100644
index 0000000..6615a58
--- /dev/null
+++ b/test/digest-template.test.ts
@@ -0,0 +1,33 @@
+import { describe, it, expect } from 'vitest'
+import { readFileSync } from 'fs'
+import { fileURLToPath } from 'url'
+import { dirname, join } from 'path'
+
+const __dirname = dirname(fileURLToPath(import.meta.url))
+const templatePath = join(__dirname, '..', 'src', 'emails', 'digest.mjml')
+const source = readFileSync(templatePath, 'utf8')
+const lines = source.split('\n')
+
+describe('digest.mjml brandAccent usage', () => {
+  it('.event-item border-left does NOT hardcode #7161FF', () => {
+    const hasHardcoded = lines.some(l => l.includes('.event-item') && l.includes('#7161FF'))
+    expect(hasHardcoded).toBe(false)
+  })
+
+  it('.footer a color does NOT hardcode #7161FF', () => {
+    const hasHardcoded = lines.some(l => l.includes('.footer a') && l.includes('#7161FF'))
+    expect(hasHardcoded).toBe(false)
+  })
+
+  it('.event-item border-left uses {{brandAccent}}', () => {
+    const eventItemLine = lines.find(l => l.includes('.event-item'))
+    expect(eventItemLine).toBeDefined()
+    expect(eventItemLine).toContain('{{brandAccent}}')
+  })
+
+  it('.footer a color uses {{brandAccent}}', () => {
+    const footerALine = lines.find(l => l.includes('.footer a'))
+    expect(footerALine).toBeDefined()
+    expect(footerALine).toContain('{{brandAccent}}')
+  })
+})
\ No newline at end of file
diff --git a/test/event-arrival-race.test.js b/test/event-arrival-race.test.js
deleted file mode 100644
index 8a938c7..0000000
--- a/test/event-arrival-race.test.js
+++ /dev/null
@@ -1,139 +0,0 @@
-#!/usr/bin/env node
-// Test: event-arrival race in digest job — fix verification
-//
-// The original bug: runJob fetched events via getEventsForSubscription(sub.id, since),
-// sent the digest (slow), then deleted events via deleteEventsForSubscription(sub.id, since)
-// which deletes EVERY row with received_at > since. Any event that arrived between
-// the fetch and the delete was also received_at > since, so it was deleted without
-// ever being emailed.
-//
-// The fix: deleteEventsByIds(sub.id, sentEventIds) deletes only the exact event IDs
-// that were fetched and sent. A late-arriving event (inserted after the fetch) has
-// a different ID and is not touched.
-//
-// This test simulates the sequence with the fixed approach:
-// 1. Create a confirmed subscription with a known last_digest_at
-// 2. Insert event A
-// 3. Fetch events for the subscription (simulating runJob's fetch)
-// 4. Insert event B after the fetch (simulating a /notify arriving during digest send)
-// 5. Delete ONLY the event A IDs (the fix — instead of timestamp-based delete)
-// 6. Verify event B survives (it arrived after fetch and was never sent)
-
-import * as db from '../dist/database.js'
-
-let passed = 0
-let failed = 0
-
-function assert(label, ok, detail) {
-  if (ok) {
-    console.log(`  ? ${label}`)
-    passed++
-  } else {
-    console.log(`  ? ${label} -- ${detail || ''}`)
-    failed++
-  }
-}
-
-function sleep(ms) {
-  return new Promise(resolve => setTimeout(resolve, ms))
-}
-
-async function main() {
-  await db.migrate()
-
-  const pubkey = 'race-test-' + Date.now()
-  const email = 'race-test-' + Date.now() + '@example.com'
-
-  // Step 1: Create and confirm subscription
-  console.log('1. Create confirmed subscription')
-  const sub = await db.insertSubscription(pubkey, email, 'daily')
-  assert('subscription created', !!sub, 'insert returned null')
-  if (!sub) { process.exit(1) }
-
-  const confirmed = await db.confirmSubscription(sub.key)
-  assert('subscription confirmed', !!confirmed, 'confirm returned null')
-  if (!confirmed) { process.exit(1) }
-
-  // Set last_digest_at to a known time well in the past.
-  // This is the "since" value runJob would use.
-  const since = Math.floor(Date.now() / 1000) - 60  // 60 seconds ago
-  await db.updateLastDigestAt(confirmed.id, since)
-
-  // Wait 1s so event received_at timestamps (whole seconds) are strictly > since.
-  await sleep(1100)
-
-  // Step 2: Insert Event A — simulates events that trigger a digest run
-  console.log('\n2. Insert Event A (triggers digest)')
-  const eventA_id = 'race-event-a-' + Date.now()
-  const eventA = {
-    id: eventA_id,
-    kind: 1,
-    pubkey: 'abc',
-    content: 'event A content',
-    created_at: Math.floor(Date.now() / 1000),
-    tags: []
-  }
-  const storedA = await db.insertEvent(eventA_id, confirmed.id, eventA, 'wss://relay.damus.io')
-  assert('Event A stored', storedA === true, `got ${storedA}`)
-
-  // Step 3: Fetch events — simulating what runJob does with since=last_digest_at
-  console.log('\n3. Fetch events for subscription (simulating runJob fetch)')
-  const fetched = await db.getEventsForSubscription(confirmed.id, since)
-  assert('Event A was fetched', fetched.some(e => e.id === eventA_id),
-    `fetched ids: [${fetched.map(e => e.id).join(', ')}]`)
-
-  // Step 4: Insert Event B after the fetch — simulating a /notify arriving
-  //         during the slow digest send (profile loads, MJML render, SMTP).
-  console.log('\n4. Insert Event B AFTER fetch (simulating event arriving during digest send)')
-  await sleep(100)  // ensure distinct received_at
-  const eventB_id = 'race-event-b-' + Date.now()
-  const eventB = {
-    id: eventB_id,
-    kind: 1,
-    pubkey: 'def',
-    content: 'event B content — arrived during send',
-    created_at: Math.floor(Date.now() / 1000),
-    tags: []
-  }
-  const storedB = await db.insertEvent(eventB_id, confirmed.id, eventB, 'wss://relay.damus.io')
-  assert('Event B stored', storedB === true, `got ${storedB}`)
-
-  // Step 5: Delete ONLY the exact event IDs that were fetched + sent — THE FIX.
-  //         Unlike the old timestamp-based delete, this does NOT touch Event B
-  //         because Event B has a different ID.
-  console.log('\n5. Delete events by exact IDs (the fix — deleteEventsByIds)')
-  const sentIds = fetched.map(e => e.id)
-  await db.deleteEventsByIds(confirmed.id, sentIds)
-  console.log('   deleted ids:', JSON.stringify(sentIds))
-
-  // Step 6: Check which events remain.
-  //         CORRECT BEHAVIOR: Only Event A (which was sent) is deleted.
-  //         Event B (which arrived after fetch) must survive.
-  console.log('\n6. Check remaining events after delete')
-  const remaining = await db.getEventsForSubscription(confirmed.id, since - 10)
-
-  const eventB_survived = remaining.some(e => e.id === eventB_id)
-  assert(
-    'Event B survives the delete (it arrived after fetch and was never sent)',
-    eventB_survived,
-    `Event B was deleted despite never being sent. ` +
-    `remaining events: [${remaining.map(e => e.id).join(', ')}]`
-  )
-
-  // Verify Event A is gone (it was sent, so deletion is correct for A)
-  const eventA_survived = remaining.some(e => e.id === eventA_id)
-  assert(
-    'Event A is deleted (it was fetched and sent)',
-    !eventA_survived,
-    `Event A should have been deleted but is still present`
-  )
-
-  console.log('')
-  console.log(`Results: ${passed} passed, ${failed} failed`)
-  process.exit(failed > 0 ? 1 : 0)
-}
-
-main().catch(err => {
-  console.error('Unhandled error in test:', err)
-  process.exit(1)
-})
\ No newline at end of file
diff --git a/test/event-arrival-race.test.ts b/test/event-arrival-race.test.ts
new file mode 100644
index 0000000..93e5c44
--- /dev/null
+++ b/test/event-arrival-race.test.ts
@@ -0,0 +1,89 @@
+import { describe, it, expect, beforeAll } from 'vitest'
+import * as db from '../src/database.js'
+
+const pubkey = 'race-test-' + Date.now()
+const email = 'race-test-' + Date.now() + '@example.com'
+let sub: any = null
+let since = 0
+const eventA_id = 'race-event-a-' + Date.now()
+const eventB_id = 'race-event-b-' + Date.now()
+
+// Captured after the initial fetch, before Event B is inserted
+let fetchedBeforeB: string[] = []
+
+function sleep(ms: number) {
+  return new Promise(resolve => setTimeout(resolve, ms))
+}
+
+describe('Event-arrival race in digest job', () => {
+  beforeAll(async () => {
+    await db.migrate()
+
+    // Create and confirm subscription
+    const s = await db.insertSubscription(pubkey, email, 'daily')
+    expect(s).toBeTruthy()
+    const confirmed = await db.confirmSubscription(s.key)
+    expect(confirmed).toBeTruthy()
+    sub = confirmed
+
+    // Set last_digest_at to 60 seconds ago (the "since" value runJob would use)
+    since = Math.floor(Date.now() / 1000) - 60
+    await db.updateLastDigestAt(sub.id, since)
+
+    // Wait 1.1s so event received_at timestamps are strictly > since
+    await sleep(1100)
+  })
+
+  it('stores Event A (triggers digest)', async () => {
+    const eventA = {
+      id: eventA_id,
+      kind: 1,
+      pubkey: 'abc',
+      content: 'event A content',
+      created_at: Math.floor(Date.now() / 1000),
+      tags: [],
+    }
+    const storedA = await db.insertEvent(eventA_id, sub.id, eventA, 'wss://relay.damus.io')
+    expect(storedA).toBe(true)
+  })
+
+  // Fetch events BEFORE Event B is inserted (simulating runJob's fetch
+  // before a /notify arrives during the digest send). Save the IDs we
+  // fetched so we delete exactly those later.
+  it('fetches events and captures IDs (simulating runJob fetch)', async () => {
+    const fetched = await db.getEventsForSubscription(sub.id, since)
+    expect(fetched.some((e: any) => e.id === eventA_id)).toBe(true)
+    fetchedBeforeB = fetched.map((e: any) => e.id)
+  })
+
+  it('stores Event B AFTER fetch (simulating arrival during digest send)', async () => {
+    await sleep(100)
+    const eventB = {
+      id: eventB_id,
+      kind: 1,
+      pubkey: 'def',
+      content: 'event B content — arrived during send',
+      created_at: Math.floor(Date.now() / 1000),
+      tags: [],
+    }
+    const storedB = await db.insertEvent(eventB_id, sub.id, eventB, 'wss://relay.damus.io')
+    expect(storedB).toBe(true)
+  })
+
+  // Delete using the IDs captured before Event B was inserted.
+  // This simulates the fix: deleteEventsByIds, not timestamp-based delete.
+  it('deletes only previously-fetched event IDs (the fix) and leaves event B', async () => {
+    await db.deleteEventsByIds(sub.id, fetchedBeforeB)
+
+    // Event B must survive (it arrived after fetch and was never sent)
+    const remaining = await db.getEventsForSubscription(sub.id, since - 10)
+    const eventB_survived = remaining.some((e: any) => e.id === eventB_id)
+    expect(eventB_survived).toBe(true)
+  })
+
+  it('Event A is deleted (it was fetched and sent)', async () => {
+    const remaining = await db.getEventsForSubscription(sub.id, since - 10)
+    const eventA_survived = remaining.some((e: any) => e.id === eventA_id)
+    expect(eventA_survived).toBe(false)
+  })
+})
\ No newline at end of file
diff --git a/test/normalize-relay-url.test.js b/test/normalize-relay-url.test.js
deleted file mode 100644
index 14a48f6..0000000
--- a/test/normalize-relay-url.test.js
+++ /dev/null
@@ -1,68 +0,0 @@
-#!/usr/bin/env node
-// FAILING test: calling normalizeRelayUrl(undefined) crashes with
-//   TypeError: can't access property "match", A is undefined
-//
-// The bug: main.ts called normalizeRelayUrl(import.meta.env.VITE_NOTIFIER_RELAY)
-// without guarding against the env var being undefined. When the env var is
-// not set, normalizeRelayUrl crashes because it calls url.match(...) on
-// undefined.
-//
-// The fix: replace the bare call with a ternary guard:
-//   const NOTIFIER_RELAY = import.meta.env.VITE_NOTIFIER_RELAY
-//     ? normalizeRelayUrl(import.meta.env.VITE_NOTIFIER_RELAY)
-//     : undefined
-//
-// This test validates that the guard pattern works correctly: when the env var
-// is falsy (undefined, empty), the app gracefully sets NOTIFIER_RELAY to
-// undefined without crashing. When it's a valid URL, normalization works.
-
-import { normalizeRelayUrl } from '/home/gascity/mailship/node_modules/.pnpm/@welshman+util@0.6.3_typescript@5.9.2/node_modules/@welshman/util/dist/util/src/Relay.js';
-
-let passed = 0;
-let failed = 0;
-
-function assert(label, ok, detail) {
-  if (ok) {
-    console.log(`  ✓ ${label}`);
-    passed++;
-  } else {
-    console.log(`  ✗ ${label} — ${detail || ''}`);
-    failed++;
-  }
-}
-
-// Test 1: Guarded normalizeRelayUrl with undefined (the exact fix pattern)
-console.log('1. Guarded normalizeRelayUrl with undefined (the fix)');
-const undefinedInput = undefined;
-const guarded1 = undefinedInput ? normalizeRelayUrl(undefinedInput) : undefined;
-assert(
-  'guarded normalizeRelayUrl with undefined should not crash, result is undefined',
-  guarded1 === undefined,
-  `got ${guarded1}`
-);
-
-// Test 2: Guard with empty string
-console.log('');
-console.log('2. Guarded normalizeRelayUrl with empty string');
-const emptyInput = '';
-const guarded2 = emptyInput ? normalizeRelayUrl(emptyInput) : undefined;
-assert(
-  'guarded normalizeRelayUrl with "" should not crash, result is undefined',
-  guarded2 === undefined,
-  `got ${guarded2}`
-);
-
-// Test 3: Guard with a valid relay still works
-console.log('');
-console.log('3. Guarded normalizeRelayUrl with valid relay');
-const validInput = 'wss://relay.damus.io';
-const guarded3 = validInput ? normalizeRelayUrl(validInput) : undefined;
-assert(
-  'guarded normalizeRelayUrl with valid input still normalizes correctly',
-  guarded3 === 'wss://relay.damus.io/',
-  `got ${guarded3}`
-);
-
-console.log('');
-console.log(`Results: ${passed} passed, ${failed} failed`);
-process.exit(failed > 0 ? 1 : 0);
diff --git a/test/normalize-relay-url.test.ts b/test/normalize-relay-url.test.ts
new file mode 100644
index 0000000..7a5c2ab
--- /dev/null
+++ b/test/normalize-relay-url.test.ts
@@ -0,0 +1,22 @@
+import { describe, it, expect } from 'vitest'
+import { normalizeRelayUrl } from '@welshman/util'
+
+describe('Guarded normalizeRelayUrl', () => {
+  it('guarded with undefined should not crash, result is undefined', () => {
+    const undefinedInput: string | undefined = undefined
+    const guarded = undefinedInput ? normalizeRelayUrl(undefinedInput) : undefined
+    expect(guarded).toBeUndefined()
+  })
+
+  it('guarded with empty string should not crash, result is undefined', () => {
+    const emptyInput = ''
+    const guarded = emptyInput ? normalizeRelayUrl(emptyInput) : undefined
+    expect(guarded).toBeUndefined()
+  })
+
+  it('guarded with valid relay still normalizes correctly', () => {
+    const validInput = 'wss://relay.damus.io'
+    const guarded = validInput ? normalizeRelayUrl(validInput) : undefined
+    expect(guarded).toBe('wss://relay.damus.io/')
+  })
+})
\ No newline at end of file
diff --git a/test/reschedule-on-frequency-change.test.js b/test/reschedule-on-frequency-change.test.js
deleted file mode 100644
index f67229f..0000000
--- a/test/reschedule-on-frequency-change.test.js
+++ /dev/null
@@ -1,83 +0,0 @@
-#!/usr/bin/env node
-// FAILING test: frequency change does not reschedule the running cron job.
-//
-// The fix: actions.ts:registerSubscription calls worker.registerSubscription()
-// after a DB update on an already-confirmed subscription, so addJob creates
-// a new CronJob with the updated frequency on the fly.
-//
-// Step 1-2: Create subscription via raw DB (bypass mailer for simplicity)
-// Step 3:   Register cron job with daily (simulating confirmSubscriptionAction)
-// Step 4:   Call registerSubscription with new frequency — the bug path
-//           BEFORE FIX: cron stays daily; AFTER FIX: cron becomes weekly
-
-import * as db from '../dist/database.js'
-import { registerSubscription } from '../dist/actions.js'
-import { getJobCronSource, removeJob } from '../dist/worker/email.js'
-import { registerSubscription as regSub } from '../dist/worker/index.js'
-
-let passed = 0
-let failed = 0
-
-function assert(label, ok, detail) {
-  if (ok) {
-    console.log(`  ? ${label}`)
-    passed++
-  } else {
-    console.log(`  ? ${label} -- ${detail || ''}`)
-    failed++
-  }
-}
-
-async function main() {
-  await db.migrate()
-
-  const pubkey = 'freq-test-' + Date.now()
-  const email = 'freq-test-' + Date.now() + '@example.com'
-
-  // Step 1: Insert subscription directly (bypass mailer) and confirm
-  console.log('1. Create confirmed subscription with daily frequency')
-  const sub = await db.insertSubscription(pubkey, email, 'daily')
-  assert('subscription created', !!sub, 'insert returned null')
-  if (!sub) { process.exit(1) }
-
-  const confirmed = await db.confirmSubscription(sub.key)
-  assert('subscription confirmed', !!confirmed, 'confirm returned null')
-  if (!confirmed) { process.exit(1) }
-
-  // Step 2: Register cron job with daily (simulating confirmSubscriptionAction)
-  console.log('\n2. Register cron job with daily frequency')
-  regSub(confirmed)
-  const dailySource = getJobCronSource(confirmed.id)
-  assert(
-    'cron source is daily',
-    dailySource === '0 0 17 * * *',
-    `expected 0 0 17 * * *, got ${dailySource}`
-  )
-
-  // Step 3: Register subscription again with weekly — the bug path.
-  //         BEFORE FIX: registerSubscription skips worker call because
-  //                      sub.confirmed_at is set → cron stays daily
-  //         AFTER FIX:  registerSubscription calls worker.registerSubscription
-  //                      → addJob reschedules → cron becomes weekly
-  console.log('\n3. Change frequency to weekly via registerSubscription')
-  await registerSubscription({ pubkey, email, frequency: 'weekly' })
-  const weeklySource = getJobCronSource(confirmed.id)
-  assert(
-    'cron source is weekly after frequency change',
-    weeklySource === '0 0 17 * * 1',
-    `expected 0 0 17 * * 1, got ${weeklySource}`
-  )
-
-  // Cleanup
-  const updated = await db.getSubscriptionByPubkey(pubkey)
-  if (updated) removeJob(updated)
-
-  console.log('')
-  console.log(`Results: ${passed} passed, ${failed} failed`)
-  process.exit(failed > 0 ? 1 : 0)
-}
-
-main().catch(err => {
-  console.error('Unhandled error in test:', err)
-  process.exit(1)
-})
\ No newline at end of file
diff --git a/test/reschedule-on-frequency-change.test.ts b/test/reschedule-on-frequency-change.test.ts
new file mode 100644
index 0000000..208ff93
--- /dev/null
+++ b/test/reschedule-on-frequency-change.test.ts
@@ -0,0 +1,42 @@
+import { describe, it, expect, beforeAll, afterAll } from 'vitest'
+import * as db from '../src/database.js'
+import { registerSubscription } from '../src/actions.js'
+import { getJobCronSource, removeJob } from '../src/worker/email.js'
+import { registerSubscription as regSub } from '../src/worker/index.js'
+
+const pubkey = 'freq-test-' + Date.now()
+const email = 'freq-test-' + Date.now() + '@example.com'
+let sub: any = null
+
+describe('Frequency change reschedules cron job', () => {
+  beforeAll(async () => {
+    await db.migrate()
+  })
+
+  it('creates confirmed subscription with daily frequency', async () => {
+    const s = await db.insertSubscription(pubkey, email, 'daily')
+    expect(s).toBeTruthy()
+    sub = s
+
+    const confirmed = await db.confirmSubscription(sub.key)
+    expect(confirmed).toBeTruthy()
+    sub = confirmed
+  })
+
+  it('registers cron job with daily frequency', () => {
+    regSub(sub)
+    const dailySource = getJobCronSource(sub.id)
+    expect(dailySource).toBe('0 0 17 * * *')
+  })
+
+  it('changes frequency to weekly via registerSubscription', async () => {
+    await registerSubscription({ pubkey, email, frequency: 'weekly' })
+    const weeklySource = getJobCronSource(sub.id)
+    expect(weeklySource).toBe('0 0 17 * * 1')
+  })
+})
+
+afterAll(async () => {
+  const updated = await db.getSubscriptionByPubkey(pubkey)
+  if (updated) removeJob(updated)
+})
\ No newline at end of file
diff --git a/test/setup.ts b/test/setup.ts
new file mode 100644
index 0000000..d67ec3f
--- /dev/null
+++ b/test/setup.ts
@@ -0,0 +1,23 @@
+// Vitest setup: set required env vars before test modules are loaded.
+// env.ts checks these at module load time; they must be present when
+// actions.ts / mailer.ts / etc. are imported.
+import { mkdirSync } from 'fs'
+
+const dataDir = 'test-data-unit'
+mkdirSync(dataDir, { recursive: true })
+
+process.env.MAILSHIP_URL = 'http://localhost:3000'
+process.env.MAILSHIP_NAME = 'Test Mailship'
+process.env.MAILSHIP_SECRET = '0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef'
+process.env.SMTP_HOST = 'localhost'
+process.env.SMTP_PORT = '587'
+process.env.SMTP_USER = 'test@test.com'
+process.env.SMTP_PASSWORD = 'test'
+process.env.SMTP_FROM = 'test@test.com'
+process.env.DEFAULT_RELAYS = 'wss://relay.damus.io'
+process.env.INDEXER_RELAYS = 'wss://purplepag.es'
+process.env.SEARCH_RELAYS = 'wss://relay.nostr.band'
+process.env.PORT = '3000'
+process.env.CORS_ORIGIN = 'http://localhost:5173'
+process.env.BASE_URL = 'http://localhost:3000'
+process.env.DATA_DIR = dataDir
\ No newline at end of file
diff --git a/test/web-ui.test.js b/test/web-ui.test.js
deleted file mode 100644
index 207bcb2..0000000
--- a/test/web-ui.test.js
+++ /dev/null
@@ -1,61 +0,0 @@
-#!/usr/bin/env node
-// Failing test: web UI crashes on load when VITE_NOTIFIER_RELAY is not set.
-//
-// The bug: `normalizeRelayUrl(import.meta.env.VITE_NOTIFIER_RELAY)` throws
-//   TypeError: Cannot read properties of undefined (reading 'match')
-// when the env var is not set.
-//
-// After the fix, `normalizeRelayUrl` is only called when the env var is
-// truthy, so the crash no longer occurs. This test verifies the guarded
-// call pattern matches the one in main.ts.
-
-import { normalizeRelayUrl } from '/home/gascity/mailship/node_modules/.pnpm/@welshman+util@0.6.3_typescript@5.9.2/node_modules/@welshman/util/dist/util/src/Relay.js';
-
-let passed = 0;
-let failed = 0;
-
-function assert(label, ok, detail) {
-  if (ok) {
-    console.log(`  ✓ ${label}`);
-    passed++;
-  } else {
-    console.log(`  ✗ ${label} — ${detail || ''}`);
-    failed++;
-  }
-}
-
-// Test 1: Guarded normalizeRelayUrl — the pattern used in main.ts
-console.log('1. Guarded normalizeRelayUrl (main.ts pattern)');
-const undefinedInput = undefined;         // simulates unset VITE_NOTIFIER_RELAY
-const guarded1 = undefinedInput ? normalizeRelayUrl(undefinedInput) : undefined;
-assert(
-  'guarded normalizeRelayUrl with undefined should not crash, result is undefined',
-  guarded1 === undefined,
-  `got ${guarded1}`
-);
-
-// Test 2: Guard with empty string
-console.log('');
-console.log('2. Guarded normalizeRelayUrl with empty string');
-const emptyInput = '';
-const guarded2 = emptyInput ? normalizeRelayUrl(emptyInput) : undefined;
-assert(
-  'guarded normalizeRelayUrl with "" should not crash, result is undefined',
-  guarded2 === undefined,
-  `got ${guarded2}`
-);
-
-// Test 3: Guard with a valid relay still works
-console.log('');
-console.log('3. Guarded normalizeRelayUrl with valid relay');
-const validInput = 'wss://relay.damus.io';
-const guarded3 = validInput ? normalizeRelayUrl(validInput) : undefined;
-assert(
-  'guarded normalizeRelayUrl with valid input still normalizes correctly',
-  guarded3 === 'wss://relay.damus.io/',
-  `got ${guarded3}`
-);
-
-console.log('');
-console.log(`Results: ${passed} passed, ${failed} failed`);
-process.exit(failed > 0 ? 1 : 0);
\ No newline at end of file
diff --git a/vitest.config.ts b/vitest.config.ts
new file mode 100644
index 0000000..255780e
--- /dev/null
+++ b/vitest.config.ts
@@ -0,0 +1,9 @@
+import { defineConfig } from 'vitest/config'
+
+export default defineConfig({
+  test: {
+    globals: true,
+    include: ['test/**/*.test.ts'],
+    setupFiles: ['test/setup.ts'],
+  },
+})
\ No newline at end of file