Job Title Expert Developer: Native 2-Way Google & Outlook Calendar Sync (OAuth 2.0) Job Description I am looking for a senior developer to build a native 2-way calendar synchronization engine for my CRM (built on Base44). We already have the basic UI and "Connect" buttons started, but we need the full backend sync logic implemented for scale. The Goal: Enable thousands of subscribers to connect their personal Google or Outlook calendars with a single click. The CRM must stay in 100% sync with their mobile devices—if they add an event on their phone, the CRM sees it. If the CRM books a lead, it appears on their phone. Technical Requirements: Native OAuth 2.0: No "middleman" services (like Nylas, Zapier, or Make). You will work directly with the Google Calendar API and Microsoft Graph API. Persistent Sync: Must implement Refresh Token logic so users only have to "Allow" once. Real-Time Updates: Implement Webhooks (Watchers) so our CRM is notified instantly when a user changes an event externally. Conflict Detection: Build the logic to check the user's "Busy" times before allowing our AI (Sarah) to book an appointment. Scalability: The code must be optimized to handle thousands of concurrent users across different time zones. Milestones Architecture Review: Verify current Base44 setup and define the database schema for token storage. Google Integration: Complete 2-way sync and webhook listener. Outlook/Office 365 Integration: Complete 2-way sync using MS Graph. Conflict Logic: Connect the sync to our AI booking flow (Sarah AI).