Kalender Sync vs shadow-planner: Features, Pricing & Which Is Better (2026)
A side-by-side comparison of Kalender Sync and shadow-planner — features, pricing, and ideal use cases — to help you decide which AI tool fits your workflow.
Kalender Sync
PPJ Venture Labs UG
GDPR-compliant calendar sync that links Outlook, Google, iCloud and more, and lets Claude, ChatGPT or other agents manage your calendars via MCP.
Key features
- Multi-Provider Calendar Sync: Connects Outlook, Google, Apple iCloud, GMX, WEB.DE, mailbox.org, kSuite, Posteo and STRATO calendars in real time, one-way or two-way.
- Visibility Levels: Choose per sync whether the target sees busy only, title and time, or full event details.
- AI Assistant Access via MCP: Remote MCP server lets Claude, ChatGPT, Codex, Cursor, Grok and OpenClaw read and manage your calendars.
- Agent-Driven Setup: Ask your connected AI agent to create syncs, find free time across calendars and schedule events.
- Per-Calendar Permissions: Grant AI access calendar by calendar, with optional write access and an access log.
- Calendar Sharing: Share a calendar with another person without exposing the underlying account.
- Credit-Based AI Usage: Monthly AI credits cover event searches, availability checks and event edits, with optional top-ups.
- GDPR Compliance: Hosted in Germany with data-protection-focused design.
Best for
- A freelancer mirrors client calendars into one personal calendar while hiding event details behind busy blocks.
- A manager with several roles keeps Outlook, Google and iCloud calendars synchronized to avoid double bookings.
- A tax advisor lets Claude find free slots across work and private calendars and book appointments.
- A coach shares availability with clients without giving access to the full calendar.
- A developer connects Claude Code or Cursor to their calendar through MCP to plan the week.
- An interim manager with multiple companies consolidates every company calendar into a single view.
shadow-planner
shadow-planner
shadow-planner is a local-first desktop Gantt planner where AI drafts full project plans from a brief and you steer schedules and workload by chat.
Key features
- AI-Drafted Plans from a Brief: Paste a markdown brief and get epics, tasks, owners and a timeline as a draft you review and edit before materializing.
- Chat-Steered Planning: Query status, workload and critical path or reschedule, re-baseline and rebalance in plain language, with diffs and approval for every destructive change.
- Local or Bring-Your-Own-Key AI: Runs on a local Ollama model fully offline by default, or on Anthropic Claude, OpenAI or OpenRouter keys with prompt caching.
- Scenarios & What-If Plans: Keep baseline, accelerated and re-org plans side by side, drafted by the agent, with snapshots and reusable templates.
- Dependency-Aware Gantt: Drag-to-reschedule with cascade preview, week-to-ten-year zoom, inline editing and holiday overlays.
- Resource Utilization Tables: Planned vs. actual person-days by project and resource with capacity-based overload colouring and epic-wide reassignment.
- Portfolio, Budgets & Audit Log: RAG status, cost and person-day rollups, per-resource daily rates, and a readable audit trail of every human or AI change with 50-step undo.
- Flexible Import/Export: Import from Excel/CSV and export to PNG, JPEG, TIFF, Mermaid, MS Project XML, JSON, Excel or CSV.
Best for
- Project Kickoff Planning: Turn a launch brief into a complete, resourced project plan in minutes.
- Capacity Management: Spot overbooked team members before a steering meeting and ask the agent to suggest a rebalance.
- Schedule Impact Analysis: Ask what breaks if a milestone slips two weeks and preview dependent task shifts.
- Roadmap Scenario Comparison: Model three alternative roadmaps in parallel and compare finish dates, person-days and peak utilization.
- Confidential Planning Offline: Plan sensitive projects on an air-gapped machine with a local model and no cloud data transfer.
- Replacing MS Project Licenses: Individual planners get desktop Gantt and resource planning with round-trip MS Project XML export for a one-time fee.