Calnio

Product Introduction

1. Definition: Calnio is a specialized, cloud-based synchronization service (SaaS) that establishes a bidirectional API bridge between Notion workspaces and Apple's iCloud Calendar ecosystem. It is a productivity tool designed for seamless data flow between task management and calendar applications.
2. Core Value Proposition: Calnio exists to solve the fragmentation between project planning in Notion and daily scheduling in Apple Calendar. Its primary value is enabling two-way Notion Apple Calendar sync, transforming Notion date properties into native, editable iCloud calendar events with full alert functionality, thereby centralizing a user's schedule.

Main Features

1. Bidirectional Real-Time Sync: Calnio's core functionality is a two-way synchronization engine. Edits made in Notion (date, time, page title) propagate to the corresponding iCloud Calendar event. Conversely, with two-way mode enabled, rescheduling, renaming, or deleting the event in Apple Calendar will update or trash the linked Notion page. The sync operates on a ~15-minute polling interval.
2. Native iCloud Event Integration: Unlike read-only .ics webcal feeds, Calnio creates genuine iCloud Calendar events via the CalDAV protocol using an app-specific password. This means events support native iOS/macOS alerts, notifications, invitees, and appear across all devices signed into the same iCloud account, just like manually created events.
3. Granular, Secure Database Mapping: Users can select specific Notion databases to sync, each generating a dedicated calendar in Apple Calendar (e.g., "Work Tasks," "Personal"). Calnio automatically identifies the date property column. All sensitive tokens (Notion integration token, iCloud app-specific password) are encrypted at rest, and the service requires minimal, scoped permissions.

Problems Solved

1. Pain Point: It eliminates the "out-of-sight, out-of-mind" problem of having critical deadlines in Notion that are missing from a user's primary calendar view, leading to missed tasks. It also solves the manual, error-prone duplication of effort between planning and scheduling apps.
2. Target Audience: The primary personas are Notion power users (students, project managers, indie developers, content creators) who rely on it for task and project management but use Apple's native calendar ecosystem (iPhone, iPad, Mac) for daily time blocking and reminders. It's ideal for those in the Apple ecosystem seeking automation.
3. Use Cases: A student can see their "Study Schedule" Notion database exams as timed events with alerts; a project manager can drag a milestone in Apple Calendar and have its due date update in the Notion project plan; a freelancer can block time for a "Client Call" directly in Calendar and have a linked Notion page created automatically.

Unique Advantages

1. Differentiation: Versus other sync tools or webcal feeds, Calnio's key differentiator is true two-way editing and real iCloud events with alerts. Competing solutions are often read-only, delayed feeds that create non-editable calendar entries without notification support.
2. Key Innovation: The technical approach of using an iCloud app-specific password to act as a CalDAV client allows Calnio to write real, manipulable events without requiring full Apple account credentials. Its architecture as a lightweight, self-hosted service by an indie developer also results in a transparent, privacy-focused model with direct user feedback channels.

Frequently Asked Questions (FAQ)

1. Is Calnio safe for my Notion and iCloud data? Yes, Calnio employs a security-first architecture. It uses encrypted storage for all sensitive access tokens, requests a limited-scope Notion integration, and requires an iCloud app-specific password (revocable at any time) instead of your main Apple ID password. Session management uses secure httpOnly cookies.
2. How does Calnio handle conflicts if I edit the same task in both apps at once? Calnio has a clear conflict resolution policy: Notion wins. If changes are detected on both the Notion page and the Apple Calendar event during a sync cycle, the data from Notion will overwrite the calendar event. This prioritizes the source of truth as your project management system.
3. What happens to my synced events if I delete my Calnio account? When you delete your account via Calnio Settings, all your data is purged from Calnio's servers and its Notion access is revoked. However, events that have already been synced to your Apple Calendar remain untouched as they are native iCloud events owned by your account.
4. Can Calnio sync repeating events or calendar invites? No, Calnio explicitly does not import or manage repeating event patterns or calendar invitations. It is designed for syncing discrete tasks and deadlines. Recurring events must be managed directly within your calendar application.
5. Is Calnio really free, and how is it sustainable? Calnio is currently completely free, with no tiered plans. It is built and maintained by an independent developer and hosted on personal infrastructure (a Raspberry Pi). The sustainability model is based on the developer's direct use of the product and community support, with transparency about data handling and costs.