CalSync is a free and open source alternative to OneCal, CalendarBridge, and Reclaim.ai. It syncs and merges events between local device calendars — no cloud servers, no accounts, no subscription. When an event appears in one calendar, CalSync automatically copies it to another using a name you choose. All syncing happens directly on your device. Your calendar data never leaves your phone. ⭐ FREE & OPEN SOURCE — No subscription, no hidden costs, no ads 📱 WORKS OFFLINE — No internet connection required, ever 🔒 100% PRIVATE — Calendar data stays on your device, period 👤 NO ACCOUNT — No signups, no logins, no personal info collected 🔄 AUTOMATIC BACKGROUND SYNC — Detects calendar changes within seconds 📝 CUSTOM EVENT NAMES — Choose what synced events are called (e.g. "Busy") 📋 SYNC PREVIEW — See exactly what will change before it happens 🗑️ DELETION MIRRORING — Remove an event from source, removed from target 🔄 RECURRING EVENTS — Repeat events stay in sync automatically 🎨 MATERIAL YOU — Adapts to your device's dynamic color theme Perfect if you need to: • Sync work and personal calendars to share availability • Prevent double-bookings across multiple calendars • Manage client calendars as a freelancer or consultant • Keep family calendars in sync without sharing login credentials If you're looking for a OneCal alternative, CalendarBridge alternative, or Reclaim.ai alternative — CalSync is the offline, private, and completely free solution. No ads. No tracking. No telemetry. Just calendar sync that works.