diff --git a/app/api/calendars/sync/discover/route.ts b/app/api/calendars/sync/discover/route.ts
new file mode 100644
index 0000000..bfc6c72
--- /dev/null
+++ b/app/api/calendars/sync/discover/route.ts
@@ -0,0 +1,83 @@
+import { NextRequest, NextResponse } from "next/server";
+import { getServerSession } from "next-auth/next";
+import { authOptions } from "@/app/api/auth/options";
+import { prisma } from "@/lib/prisma";
+import { discoverInfomaniakCalendars } from "@/lib/services/caldav-sync";
+import { logger } from "@/lib/logger";
+
+/**
+ * Discover CalDAV calendars for an Infomaniak email account
+ * POST /api/calendars/sync/discover
+ */
+export async function POST(req: NextRequest) {
+  try {
+    const session = await getServerSession(authOptions);
+    if (!session?.user?.id) {
+      return NextResponse.json({ error: "Non authentifié" }, { status: 401 });
+    }
+
+    const { mailCredentialId } = await req.json();
+
+    if (!mailCredentialId) {
+      return NextResponse.json(
+        { error: "mailCredentialId est requis" },
+        { status: 400 }
+      );
+    }
+
+    // Get mail credentials
+    const mailCreds = await prisma.mailCredentials.findFirst({
+      where: {
+        id: mailCredentialId,
+        userId: session.user.id,
+      },
+    });
+
+    if (!mailCreds) {
+      return NextResponse.json(
+        { error: "Credentials non trouvés" },
+        { status: 404 }
+      );
+    }
+
+    // Check if it's an Infomaniak account
+    if (!mailCreds.host.includes('infomaniak')) {
+      return NextResponse.json(
+        { error: "Ce compte n'est pas un compte Infomaniak" },
+        { status: 400 }
+      );
+    }
+
+    if (!mailCreds.password) {
+      return NextResponse.json(
+        { error: "Mot de passe requis pour la synchronisation CalDAV" },
+        { status: 400 }
+      );
+    }
+
+    // Discover calendars
+    const calendars = await discoverInfomaniakCalendars(
+      mailCreds.email,
+      mailCreds.password
+    );
+
+    logger.info('Calendars discovered', {
+      userId: session.user.id,
+      email: mailCreds.email,
+      calendarsCount: calendars.length,
+    });
+
+    return NextResponse.json({ calendars });
+  } catch (error) {
+    logger.error('Error discovering calendars', {
+      error: error instanceof Error ? error.message : String(error),
+    });
+    return NextResponse.json(
+      {
+        error: "Erreur lors de la découverte des calendriers",
+        details: error instanceof Error ? error.message : String(error),
+      },
+      { status: 500 }
+    );
+  }
+}
diff --git a/app/api/calendars/sync/job/route.ts b/app/api/calendars/sync/job/route.ts
new file mode 100644
index 0000000..b4c3857
--- /dev/null
+++ b/app/api/calendars/sync/job/route.ts
@@ -0,0 +1,49 @@
+import { NextRequest, NextResponse } from "next/server";
+import { getServerSession } from "next-auth/next";
+import { authOptions } from "@/app/api/auth/options";
+import { runCalendarSyncJob } from "@/lib/services/calendar-sync-job";
+import { logger } from "@/lib/logger";
+
+/**
+ * Trigger calendar sync job manually (admin only or cron)
+ * POST /api/calendars/sync/job
+ */
+export async function POST(req: NextRequest) {
+  try {
+    const session = await getServerSession(authOptions);
+    
+    // Check for API key in header (for cron jobs)
+    const apiKey = req.headers.get('x-api-key');
+    const isCronRequest = apiKey === process.env.CALENDAR_SYNC_API_KEY;
+
+    if (!session?.user?.id && !isCronRequest) {
+      return NextResponse.json({ error: "Non authentifié" }, { status: 401 });
+    }
+
+    // If authenticated, check if user is admin
+    if (session?.user?.id && !session.user.role?.includes('ROLE_Admin') && !isCronRequest) {
+      return NextResponse.json({ error: "Non autorisé" }, { status: 403 });
+    }
+
+    logger.info('Manual calendar sync job triggered', {
+      userId: session?.user?.id,
+      isCronRequest,
+    });
+
+    // Run sync job
+    await runCalendarSyncJob();
+
+    return NextResponse.json({ success: true, message: "Synchronisation terminée" });
+  } catch (error) {
+    logger.error('Error running calendar sync job', {
+      error: error instanceof Error ? error.message : String(error),
+    });
+    return NextResponse.json(
+      {
+        error: "Erreur lors de la synchronisation",
+        details: error instanceof Error ? error.message : String(error),
+      },
+      { status: 500 }
+    );
+  }
+}
diff --git a/app/api/calendars/sync/route.ts b/app/api/calendars/sync/route.ts
new file mode 100644
index 0000000..25ed354
--- /dev/null
+++ b/app/api/calendars/sync/route.ts
@@ -0,0 +1,248 @@
+import { NextRequest, NextResponse } from "next/server";
+import { getServerSession } from "next-auth/next";
+import { authOptions } from "@/app/api/auth/options";
+import { prisma } from "@/lib/prisma";
+import { syncInfomaniakCalendar } from "@/lib/services/caldav-sync";
+import { logger } from "@/lib/logger";
+
+/**
+ * Create a calendar sync configuration
+ * POST /api/calendars/sync
+ */
+export async function POST(req: NextRequest) {
+  try {
+    const session = await getServerSession(authOptions);
+    if (!session?.user?.id) {
+      return NextResponse.json({ error: "Non authentifié" }, { status: 401 });
+    }
+
+    const { calendarId, mailCredentialId, externalCalendarUrl, externalCalendarId, syncFrequency } = await req.json();
+
+    if (!calendarId || !mailCredentialId || !externalCalendarUrl) {
+      return NextResponse.json(
+        { error: "calendarId, mailCredentialId et externalCalendarUrl sont requis" },
+        { status: 400 }
+      );
+    }
+
+    // Verify calendar belongs to user
+    const calendar = await prisma.calendar.findFirst({
+      where: {
+        id: calendarId,
+        userId: session.user.id,
+      },
+    });
+
+    if (!calendar) {
+      return NextResponse.json(
+        { error: "Calendrier non trouvé" },
+        { status: 404 }
+      );
+    }
+
+    // Verify mail credentials belong to user
+    const mailCreds = await prisma.mailCredentials.findFirst({
+      where: {
+        id: mailCredentialId,
+        userId: session.user.id,
+      },
+    });
+
+    if (!mailCreds) {
+      return NextResponse.json(
+        { error: "Credentials non trouvés" },
+        { status: 404 }
+      );
+    }
+
+    // Create or update sync configuration
+    const syncConfig = await prisma.calendarSync.upsert({
+      where: { calendarId },
+      create: {
+        calendarId,
+        mailCredentialId,
+        provider: 'infomaniak',
+        externalCalendarId: externalCalendarId || null,
+        externalCalendarUrl,
+        syncEnabled: true,
+        syncFrequency: syncFrequency || 15,
+      },
+      update: {
+        mailCredentialId,
+        externalCalendarId: externalCalendarId || null,
+        externalCalendarUrl,
+        syncFrequency: syncFrequency || 15,
+        syncEnabled: true,
+      },
+    });
+
+    // Trigger initial sync
+    try {
+      await syncInfomaniakCalendar(syncConfig.id, true);
+    } catch (syncError) {
+      logger.error('Error during initial sync', {
+        syncConfigId: syncConfig.id,
+        error: syncError instanceof Error ? syncError.message : String(syncError),
+      });
+      // Don't fail the request if sync fails, just log it
+    }
+
+    return NextResponse.json({ syncConfig });
+  } catch (error) {
+    logger.error('Error creating calendar sync', {
+      error: error instanceof Error ? error.message : String(error),
+    });
+    return NextResponse.json(
+      {
+        error: "Erreur lors de la création de la synchronisation",
+        details: error instanceof Error ? error.message : String(error),
+      },
+      { status: 500 }
+    );
+  }
+}
+
+/**
+ * Trigger manual sync for a calendar
+ * PUT /api/calendars/sync
+ */
+export async function PUT(req: NextRequest) {
+  try {
+    const session = await getServerSession(authOptions);
+    if (!session?.user?.id) {
+      return NextResponse.json({ error: "Non authentifié" }, { status: 401 });
+    }
+
+    const { calendarSyncId } = await req.json();
+
+    if (!calendarSyncId) {
+      return NextResponse.json(
+        { error: "calendarSyncId est requis" },
+        { status: 400 }
+      );
+    }
+
+    // Verify sync config belongs to user
+    const syncConfig = await prisma.calendarSync.findUnique({
+      where: { id: calendarSyncId },
+      include: {
+        calendar: true,
+      },
+    });
+
+    if (!syncConfig || syncConfig.calendar.userId !== session.user.id) {
+      return NextResponse.json(
+        { error: "Synchronisation non trouvée" },
+        { status: 404 }
+      );
+    }
+
+    // Trigger sync
+    const result = await syncInfomaniakCalendar(calendarSyncId, true);
+
+    return NextResponse.json({ success: true, result });
+  } catch (error) {
+    logger.error('Error triggering calendar sync', {
+      error: error instanceof Error ? error.message : String(error),
+    });
+    return NextResponse.json(
+      {
+        error: "Erreur lors de la synchronisation",
+        details: error instanceof Error ? error.message : String(error),
+      },
+      { status: 500 }
+    );
+  }
+}
+
+/**
+ * Get sync status for user calendars
+ * GET /api/calendars/sync
+ */
+export async function GET(req: NextRequest) {
+  try {
+    const session = await getServerSession(authOptions);
+    if (!session?.user?.id) {
+      return NextResponse.json({ error: "Non authentifié" }, { status: 401 });
+    }
+
+    const syncConfigs = await prisma.calendarSync.findMany({
+      where: {
+        calendar: {
+          userId: session.user.id,
+        },
+      },
+      include: {
+        calendar: true,
+        mailCredential: {
+          select: {
+            id: true,
+            email: true,
+            display_name: true,
+          },
+        },
+      },
+    });
+
+    return NextResponse.json({ syncConfigs });
+  } catch (error) {
+    logger.error('Error fetching sync configs', {
+      error: error instanceof Error ? error.message : String(error),
+    });
+    return NextResponse.json(
+      { error: "Erreur serveur" },
+      { status: 500 }
+    );
+  }
+}
+
+/**
+ * Delete sync configuration
+ * DELETE /api/calendars/sync
+ */
+export async function DELETE(req: NextRequest) {
+  try {
+    const session = await getServerSession(authOptions);
+    if (!session?.user?.id) {
+      return NextResponse.json({ error: "Non authentifié" }, { status: 401 });
+    }
+
+    const { calendarSyncId } = await req.json();
+
+    if (!calendarSyncId) {
+      return NextResponse.json(
+        { error: "calendarSyncId est requis" },
+        { status: 400 }
+      );
+    }
+
+    // Verify sync config belongs to user
+    const syncConfig = await prisma.calendarSync.findUnique({
+      where: { id: calendarSyncId },
+      include: {
+        calendar: true,
+      },
+    });
+
+    if (!syncConfig || syncConfig.calendar.userId !== session.user.id) {
+      return NextResponse.json(
+        { error: "Synchronisation non trouvée" },
+        { status: 404 }
+      );
+    }
+
+    await prisma.calendarSync.delete({
+      where: { id: calendarSyncId },
+    });
+
+    return NextResponse.json({ success: true });
+  } catch (error) {
+    logger.error('Error deleting sync config', {
+      error: error instanceof Error ? error.message : String(error),
+    });
+    return NextResponse.json(
+      { error: "Erreur serveur" },
+      { status: 500 }
+    );
+  }
+}
diff --git a/lib/services/caldav-sync.ts b/lib/services/caldav-sync.ts
new file mode 100644
index 0000000..b31d92d
--- /dev/null
+++ b/lib/services/caldav-sync.ts
@@ -0,0 +1,474 @@
+import { createClient, WebDAVClient } from 'webdav';
+import { prisma } from '@/lib/prisma';
+import { logger } from '@/lib/logger';
+
+export interface CalDAVCalendar {
+  id: string;
+  name: string;
+  url: string;
+  color?: string;
+}
+
+export interface CalDAVEvent {
+  uid: string;
+  summary: string;
+  description?: string;
+  start: Date;
+  end: Date;
+  location?: string;
+  allDay: boolean;
+}
+
+/**
+ * Get CalDAV client for Infomaniak account
+ */
+export async function getInfomaniakCalDAVClient(
+  email: string,
+  password: string
+): Promise<WebDAVClient> {
+  // Infomaniak CalDAV base URL
+  const baseUrl = 'https://sync.infomaniak.com/caldav';
+  
+  const client = createClient(baseUrl, {
+    username: email,
+    password: password,
+  });
+
+  return client;
+}
+
+/**
+ * Discover calendars available for an Infomaniak account
+ */
+export async function discoverInfomaniakCalendars(
+  email: string,
+  password: string
+): Promise<CalDAVCalendar[]> {
+  try {
+    const client = await getInfomaniakCalDAVClient(email, password);
+    
+    // List all calendars using PROPFIND
+    const items = await client.getDirectoryContents('/');
+    
+    const calendars: CalDAVCalendar[] = [];
+    
+    for (const item of items) {
+      if (item.type === 'directory' && item.filename !== '/') {
+        // Get calendar properties
+        try {
+          const props = await client.customRequest(item.filename, {
+            method: 'PROPFIND',
+            headers: {
+              Depth: '0',
+              'Content-Type': 'application/xml',
+            },
+            data: `<?xml version="1.0" encoding="utf-8" ?>
+<d:propfind xmlns:d="DAV:" xmlns:c="urn:ietf:params:xml:ns:caldav">
+  <d:prop>
+    <d:displayname />
+    <c:calendar-color />
+  </d:prop>
+</d:propfind>`,
+          });
+
+          // Parse XML response to extract calendar name and color
+          const displayName = extractDisplayName(props.data);
+          const color = extractCalendarColor(props.data);
+
+          calendars.push({
+            id: item.filename.replace(/^\//, '').replace(/\/$/, ''),
+            name: displayName || item.basename || 'Calendrier',
+            url: item.filename,
+            color: color,
+          });
+        } catch (error) {
+          logger.error('Error fetching calendar properties', {
+            calendar: item.filename,
+            error: error instanceof Error ? error.message : String(error),
+          });
+          // Still add the calendar with default name
+          calendars.push({
+            id: item.filename.replace(/^\//, '').replace(/\/$/, ''),
+            name: item.basename || 'Calendrier',
+            url: item.filename,
+          });
+        }
+      }
+    }
+
+    return calendars;
+  } catch (error) {
+    logger.error('Error discovering Infomaniak calendars', {
+      email,
+      error: error instanceof Error ? error.message : String(error),
+    });
+    throw error;
+  }
+}
+
+/**
+ * Extract display name from PROPFIND XML response
+ */
+function extractDisplayName(xmlData: string): string | null {
+  try {
+    const match = xmlData.match(/<d:displayname[^>]*>([^<]+)<\/d:displayname>/i);
+    return match ? match[1] : null;
+  } catch {
+    return null;
+  }
+}
+
+/**
+ * Extract calendar color from PROPFIND XML response
+ */
+function extractCalendarColor(xmlData: string): string | undefined {
+  try {
+    const match = xmlData.match(/<c:calendar-color[^>]*>([^<]+)<\/c:calendar-color>/i);
+    return match ? match[1] : undefined;
+  } catch {
+    return undefined;
+  }
+}
+
+/**
+ * Fetch events from a CalDAV calendar
+ */
+export async function fetchCalDAVEvents(
+  email: string,
+  password: string,
+  calendarUrl: string,
+  startDate?: Date,
+  endDate?: Date
+): Promise<CalDAVEvent[]> {
+  try {
+    const client = await getInfomaniakCalDAVClient(email, password);
+    
+    // Build calendar query URL
+    const queryUrl = calendarUrl.endsWith('/') ? calendarUrl : `${calendarUrl}/`;
+    
+    // Build CALDAV query XML
+    const start = startDate ? startDate.toISOString().replace(/[-:]/g, '').split('.')[0] + 'Z' : '';
+    const end = endDate ? endDate.toISOString().replace(/[-:]/g, '').split('.')[0] + 'Z' : '';
+    
+    const queryXml = `<?xml version="1.0" encoding="utf-8" ?>
+<C:calendar-query xmlns:D="DAV:" xmlns:C="urn:ietf:params:xml:ns:caldav">
+  <D:prop>
+    <D:getetag />
+    <C:calendar-data />
+  </D:prop>
+  ${start && end ? `
+  <C:filter>
+    <C:comp-filter name="VCALENDAR">
+      <C:comp-filter name="VEVENT">
+        <C:time-range start="${start}" end="${end}" />
+      </C:comp-filter>
+    </C:comp-filter>
+  </C:filter>` : ''}
+</C:calendar-query>`;
+
+    const response = await client.customRequest(queryUrl, {
+      method: 'REPORT',
+      headers: {
+        Depth: '1',
+        'Content-Type': 'application/xml',
+      },
+      data: queryXml,
+    });
+
+    // Parse iCalendar data from response
+    const events = parseICalendarEvents(response.data);
+    
+    return events;
+  } catch (error) {
+    logger.error('Error fetching CalDAV events', {
+      email,
+      calendarUrl,
+      error: error instanceof Error ? error.message : String(error),
+    });
+    throw error;
+  }
+}
+
+/**
+ * Parse iCalendar format events from CalDAV response
+ */
+function parseICalendarEvents(icalData: string): CalDAVEvent[] {
+  const events: CalDAVEvent[] = [];
+  
+  // Split by BEGIN:VEVENT
+  const eventBlocks = icalData.split(/BEGIN:VEVENT/gi);
+  
+  for (const block of eventBlocks.slice(1)) { // Skip first empty block
+    try {
+      const event = parseICalendarEvent(block);
+      if (event) {
+        events.push(event);
+      }
+    } catch (error) {
+      logger.error('Error parsing iCalendar event', {
+        error: error instanceof Error ? error.message : String(error),
+      });
+    }
+  }
+  
+  return events;
+}
+
+/**
+ * Parse a single iCalendar event block
+ */
+function parseICalendarEvent(block: string): CalDAVEvent | null {
+  const lines = block.split(/\r?\n/);
+  
+  let uid: string | null = null;
+  let summary: string | null = null;
+  let description: string | undefined;
+  let dtstart: string | null = null;
+  let dtend: string | null = null;
+  let location: string | undefined;
+  let allDay = false;
+  
+  for (let i = 0; i < lines.length; i++) {
+    let line = lines[i];
+    
+    // Handle line continuation (lines starting with space)
+    while (i + 1 < lines.length && lines[i + 1].startsWith(' ')) {
+      line += lines[i + 1].substring(1);
+      i++;
+    }
+    
+    if (line.startsWith('UID:')) {
+      uid = line.substring(4).trim();
+    } else if (line.startsWith('SUMMARY:')) {
+      summary = line.substring(8).trim();
+    } else if (line.startsWith('DESCRIPTION:')) {
+      description = line.substring(12).trim();
+    } else if (line.startsWith('DTSTART')) {
+      const match = line.match(/DTSTART(?:;VALUE=DATE)?:([^;]+)/);
+      if (match) {
+        dtstart = match[1];
+        allDay = line.includes('VALUE=DATE');
+      }
+    } else if (line.startsWith('DTEND')) {
+      const match = line.match(/DTEND(?:;VALUE=DATE)?:([^;]+)/);
+      if (match) {
+        dtend = match[1];
+      }
+    } else if (line.startsWith('LOCATION:')) {
+      location = line.substring(9).trim();
+    }
+  }
+  
+  if (!uid || !summary || !dtstart || !dtend) {
+    return null;
+  }
+  
+  // Parse dates
+  const start = parseICalendarDate(dtstart, allDay);
+  const end = parseICalendarDate(dtend, allDay);
+  
+  if (!start || !end) {
+    return null;
+  }
+  
+  return {
+    uid,
+    summary,
+    description,
+    start,
+    end,
+    location,
+    allDay,
+  };
+}
+
+/**
+ * Parse iCalendar date format (YYYYMMDDTHHmmssZ or YYYYMMDD)
+ */
+function parseICalendarDate(dateStr: string, allDay: boolean): Date | null {
+  try {
+    if (allDay) {
+      // Format: YYYYMMDD
+      const year = parseInt(dateStr.substring(0, 4));
+      const month = parseInt(dateStr.substring(4, 6)) - 1; // Month is 0-indexed
+      const day = parseInt(dateStr.substring(6, 8));
+      return new Date(year, month, day);
+    } else {
+      // Format: YYYYMMDDTHHmmssZ or YYYYMMDDTHHmmss
+      const cleanDate = dateStr.replace(/[TZ]/g, '');
+      const year = parseInt(cleanDate.substring(0, 4));
+      const month = parseInt(cleanDate.substring(4, 6)) - 1;
+      const day = parseInt(cleanDate.substring(6, 8));
+      const hour = cleanDate.length > 8 ? parseInt(cleanDate.substring(9, 11)) : 0;
+      const minute = cleanDate.length > 10 ? parseInt(cleanDate.substring(11, 13)) : 0;
+      const second = cleanDate.length > 12 ? parseInt(cleanDate.substring(13, 15)) : 0;
+      
+      const date = new Date(year, month, day, hour, minute, second);
+      
+      // If timezone is UTC (Z), convert to local time
+      if (dateStr.includes('Z')) {
+        return new Date(date.getTime() - date.getTimezoneOffset() * 60000);
+      }
+      
+      return date;
+    }
+  } catch (error) {
+    logger.error('Error parsing iCalendar date', {
+      dateStr,
+      error: error instanceof Error ? error.message : String(error),
+    });
+    return null;
+  }
+}
+
+/**
+ * Sync events from Infomaniak CalDAV calendar to local Prisma calendar
+ */
+export async function syncInfomaniakCalendar(
+  calendarSyncId: string,
+  forceSync: boolean = false
+): Promise<{ synced: number; created: number; updated: number; deleted: number }> {
+  try {
+    const syncConfig = await prisma.calendarSync.findUnique({
+      where: { id: calendarSyncId },
+      include: {
+        calendar: true,
+        mailCredential: true,
+      },
+    });
+
+    if (!syncConfig || !syncConfig.syncEnabled) {
+      throw new Error('Calendar sync not enabled or not found');
+    }
+
+    if (!syncConfig.mailCredential) {
+      throw new Error('Mail credentials not found for calendar sync');
+    }
+
+    const creds = syncConfig.mailCredential;
+    
+    // Check if sync is needed (based on syncFrequency)
+    if (!forceSync && syncConfig.lastSyncAt) {
+      const minutesSinceLastSync = (Date.now() - syncConfig.lastSyncAt.getTime()) / (1000 * 60);
+      if (minutesSinceLastSync < syncConfig.syncFrequency) {
+        logger.debug('Sync skipped - too soon since last sync', {
+          calendarSyncId,
+          minutesSinceLastSync,
+          syncFrequency: syncConfig.syncFrequency,
+        });
+        return { synced: 0, created: 0, updated: 0, deleted: 0 };
+      }
+    }
+
+    if (!creds.password) {
+      throw new Error('Password required for Infomaniak CalDAV sync');
+    }
+
+    // Fetch events from CalDAV
+    const startDate = new Date();
+    startDate.setMonth(startDate.getMonth() - 1); // Sync last month to next 3 months
+    const endDate = new Date();
+    endDate.setMonth(endDate.getMonth() + 3);
+
+    const caldavEvents = await fetchCalDAVEvents(
+      creds.email,
+      creds.password,
+      syncConfig.externalCalendarUrl || '',
+      startDate,
+      endDate
+    );
+
+    // Get existing events in local calendar
+    const existingEvents = await prisma.event.findMany({
+      where: {
+        calendarId: syncConfig.calendarId,
+      },
+    });
+
+    // Create a map of existing events by external UID
+    const existingEventsMap = new Map<string, typeof existingEvents[0]>();
+    // Store events that have external UID in metadata (we'll need to add this field)
+    // For now, we'll match by title and date
+
+    let created = 0;
+    let updated = 0;
+    let deleted = 0;
+
+    // Sync events: create or update
+    for (const caldavEvent of caldavEvents) {
+      // Try to find existing event by matching title and start date
+      const existingEvent = existingEvents.find(
+        (e) =>
+          e.title === caldavEvent.summary &&
+          Math.abs(new Date(e.start).getTime() - caldavEvent.start.getTime()) < 60000 // Within 1 minute
+      );
+
+      const eventData = {
+        title: caldavEvent.summary,
+        description: caldavEvent.description || null,
+        start: caldavEvent.start,
+        end: caldavEvent.end,
+        location: caldavEvent.location || null,
+        isAllDay: caldavEvent.allDay,
+        calendarId: syncConfig.calendarId,
+        userId: syncConfig.calendar.userId,
+      };
+
+      if (existingEvent) {
+        // Update existing event
+        await prisma.event.update({
+          where: { id: existingEvent.id },
+          data: eventData,
+        });
+        updated++;
+      } else {
+        // Create new event
+        await prisma.event.create({
+          data: eventData,
+        });
+        created++;
+      }
+    }
+
+    // Update sync timestamp
+    await prisma.calendarSync.update({
+      where: { id: calendarSyncId },
+      data: {
+        lastSyncAt: new Date(),
+        lastSyncError: null,
+      },
+    });
+
+    logger.info('Calendar sync completed', {
+      calendarSyncId,
+      calendarId: syncConfig.calendarId,
+      synced: caldavEvents.length,
+      created,
+      updated,
+    });
+
+    return {
+      synced: caldavEvents.length,
+      created,
+      updated,
+      deleted,
+    };
+  } catch (error) {
+    logger.error('Error syncing calendar', {
+      calendarSyncId,
+      error: error instanceof Error ? error.message : String(error),
+    });
+
+    // Update sync error
+    await prisma.calendarSync.update({
+      where: { id: calendarSyncId },
+      data: {
+        lastSyncError: error instanceof Error ? error.message : String(error),
+      },
+    }).catch(() => {
+      // Ignore errors updating sync error
+    });
+
+    throw error;
+  }
+}
diff --git a/lib/services/calendar-sync-job.ts b/lib/services/calendar-sync-job.ts
new file mode 100644
index 0000000..dd61c5f
--- /dev/null
+++ b/lib/services/calendar-sync-job.ts
@@ -0,0 +1,79 @@
+import { prisma } from '@/lib/prisma';
+import { syncInfomaniakCalendar } from './caldav-sync';
+import { logger } from '@/lib/logger';
+
+/**
+ * Run periodic sync for all enabled calendar syncs
+ * This should be called by a cron job or scheduled task
+ */
+export async function runCalendarSyncJob(): Promise<void> {
+  try {
+    logger.info('Starting calendar sync job');
+
+    // Get all enabled sync configurations that need syncing
+    const syncConfigs = await prisma.calendarSync.findMany({
+      where: {
+        syncEnabled: true,
+      },
+      include: {
+        calendar: true,
+        mailCredential: true,
+      },
+    });
+
+    logger.info('Found sync configurations', {
+      count: syncConfigs.length,
+    });
+
+    const results = {
+      total: syncConfigs.length,
+      successful: 0,
+      failed: 0,
+      skipped: 0,
+    };
+
+    for (const syncConfig of syncConfigs) {
+      try {
+        // Check if sync is needed
+        if (syncConfig.lastSyncAt) {
+          const minutesSinceLastSync =
+            (Date.now() - syncConfig.lastSyncAt.getTime()) / (1000 * 60);
+          if (minutesSinceLastSync < syncConfig.syncFrequency) {
+            logger.debug('Sync skipped - too soon', {
+              calendarSyncId: syncConfig.id,
+              minutesSinceLastSync,
+              syncFrequency: syncConfig.syncFrequency,
+            });
+            results.skipped++;
+            continue;
+          }
+        }
+
+        // Sync based on provider
+        if (syncConfig.provider === 'infomaniak') {
+          await syncInfomaniakCalendar(syncConfig.id, false);
+          results.successful++;
+        } else {
+          logger.warn('Unknown sync provider', {
+            calendarSyncId: syncConfig.id,
+            provider: syncConfig.provider,
+          });
+          results.skipped++;
+        }
+      } catch (error) {
+        logger.error('Error syncing calendar', {
+          calendarSyncId: syncConfig.id,
+          error: error instanceof Error ? error.message : String(error),
+        });
+        results.failed++;
+      }
+    }
+
+    logger.info('Calendar sync job completed', results);
+  } catch (error) {
+    logger.error('Error running calendar sync job', {
+      error: error instanceof Error ? error.message : String(error),
+    });
+    throw error;
+  }
+}
diff --git a/package.json b/package.json
index 982c913..ed28bdf 100644
--- a/package.json
+++ b/package.json
@@ -11,6 +11,7 @@
     "start": "next start",
     "lint": "next lint",
     "sync-users": "node scripts/sync-users.js",
+    "sync-calendars": "node scripts/sync-calendars.js",
     "migrate:dev": "prisma migrate dev",
     "migrate:deploy": "prisma migrate deploy",
     "migrate:status": "prisma migrate status",
diff --git a/prisma/schema.prisma b/prisma/schema.prisma
index 37cb70d..75a1bd0 100644
--- a/prisma/schema.prisma
+++ b/prisma/schema.prisma
@@ -39,6 +39,7 @@ model Calendar {
   events      Event[]
   user        User     @relation(fields: [userId], references: [id], onDelete: Cascade)
   mission     Mission?  @relation(fields: [missionId], references: [id], onDelete: Cascade)
+  syncConfig  CalendarSync? // Optional: sync configuration for external calendars
 
   @@index([userId])
   @@index([missionId])
@@ -90,6 +91,7 @@ model MailCredentials {
   createdAt DateTime @default(now())
   updatedAt DateTime @updatedAt
   user      User     @relation(fields: [userId], references: [id], onDelete: Cascade)
+  calendarSyncs CalendarSync[] // Calendars synced from this email account
 
   @@unique([userId, email])
   @@index([userId])
@@ -187,4 +189,27 @@ model MissionUser {
   @@unique([missionId, userId, role])
   @@index([missionId])
   @@index([userId])
+}
+
+// Calendar synchronization configuration for external calendars (CalDAV, etc.)
+model CalendarSync {
+  id              String   @id @default(uuid())
+  calendarId      String   @unique // Link to local calendar
+  mailCredentialId String? // Link to MailCredentials for Infomaniak accounts
+  provider        String   // "infomaniak", "microsoft", "google", etc.
+  externalCalendarId String? // ID of the calendar in the external system
+  externalCalendarUrl String? // Full CalDAV URL for the calendar
+  syncEnabled     Boolean  @default(true)
+  lastSyncAt      DateTime?
+  syncFrequency   Int      @default(15) // minutes between syncs
+  lastSyncError   String?  // Store last error message if sync failed
+  createdAt       DateTime @default(now())
+  updatedAt       DateTime @updatedAt
+  
+  calendar        Calendar @relation(fields: [calendarId], references: [id], onDelete: Cascade)
+  mailCredential  MailCredentials? @relation(fields: [mailCredentialId], references: [id], onDelete: Cascade)
+
+  @@index([calendarId])
+  @@index([mailCredentialId])
+  @@index([provider])
 }
\ No newline at end of file
diff --git a/scripts/sync-calendars.js b/scripts/sync-calendars.js
new file mode 100644
index 0000000..e7fd22e
--- /dev/null
+++ b/scripts/sync-calendars.js
@@ -0,0 +1,78 @@
+/**
+ * Calendar sync job script
+ * Run this periodically (e.g., every 15 minutes) to sync external calendars
+ * 
+ * Usage:
+ *   node scripts/sync-calendars.js
+ * 
+ * Or via cron:
+ *   */15 * * * * cd /path/to/NeahStable && node scripts/sync-calendars.js >> /var/log/calendar-sync.log 2>&1
+ * 
+ * Or call the API endpoint:
+ *   curl -X POST http://localhost:3000/api/calendars/sync/job -H "x-api-key: YOUR_API_KEY"
+ */
+
+// For now, this script calls the API endpoint
+// In production, you can use this or call the API directly
+
+const http = require('http');
+const https = require('https');
+
+const API_URL = process.env.CALENDAR_SYNC_API_URL || 'http://localhost:3000';
+const API_KEY = process.env.CALENDAR_SYNC_API_KEY || '';
+
+async function callSyncAPI() {
+  return new Promise((resolve, reject) => {
+    const url = new URL(`${API_URL}/api/calendars/sync/job`);
+    const client = url.protocol === 'https:' ? https : http;
+    
+    const options = {
+      method: 'POST',
+      headers: {
+        'Content-Type': 'application/json',
+        'x-api-key': API_KEY,
+      },
+    };
+
+    const req = client.request(url, options, (res) => {
+      let data = '';
+      
+      res.on('data', (chunk) => {
+        data += chunk;
+      });
+      
+      res.on('end', () => {
+        if (res.statusCode === 200) {
+          console.log(`[${new Date().toISOString()}] Sync completed successfully`);
+          resolve(JSON.parse(data));
+        } else {
+          console.error(`[${new Date().toISOString()}] Sync failed:`, data);
+          reject(new Error(`HTTP ${res.statusCode}: ${data}`));
+        }
+      });
+    });
+
+    req.on('error', (error) => {
+      console.error(`[${new Date().toISOString()}] Request error:`, error);
+      reject(error);
+    });
+
+    req.end();
+  });
+}
+
+async function runSync() {
+  try {
+    console.log(`[${new Date().toISOString()}] Starting calendar sync job`);
+    
+    await callSyncAPI();
+    
+    console.log(`[${new Date().toISOString()}] Calendar sync job completed successfully`);
+    process.exit(0);
+  } catch (error) {
+    console.error(`[${new Date().toISOString()}] Error running calendar sync job:`, error.message);
+    process.exit(1);
+  }
+}
+
+runSync();