# Best calendar and scheduling APIs for AI agents (slim)

> Google Calendar API (A), Nylas Calendar and Scheduler API (BB) and Calendly API + MCP (B) lead the 10 ranked calendar and scheduling APIs. Picks by need, strengths, weaknesses and prices from the Anchor benchmark.

- Full: https://www.anchorterminal.com/best/scheduling/index.md (~5,350 tokens) · this version ~1,330 tokens · JSON https://www.anchorterminal.com/best/scheduling/index.json · canonical https://www.anchorterminal.com/best/scheduling/
- Index: https://www.anchorterminal.com/llms.txt · API: https://www.anchorterminal.com/api/v1/index.json · Updated: 2026-10-09

All 10 ranked calendar and scheduling APIs on the Anchor benchmark, with a pick for each need and where each one falls short. Scores come from public evidence, re-checked as vendors change.

- Ranked: 10 · agent-ready (BB or better): 2 · accept x402: 0 · hosted endpoints: 10
- Full ranked table: https://www.anchorterminal.com/categories/scheduling.md
- Head-to-head comparisons: https://www.anchorterminal.com/compare/scheduling/index.md (45)
- Methodology: https://www.anchorterminal.com/benchmark/index.md

## The shortlist

| # | Tool | Grade | Score | Best for | Price | Where |
| --- | --- | --- | --- | --- | --- | --- |
| 1 | [Google Calendar API](https://www.anchorterminal.com/tools/google-calendar-api.md) | A | 80.6 | An agent acting on Google Workspace or Gmail users' own calendars with tight scopes and no per-account fee. | Free | hosted |
| 2 | [Nylas Calendar and Scheduler API](https://www.anchorterminal.com/tools/nylas-calendar.md) | BB | 71 | Products that need read, write and availability across every major provider plus email on one grant, from a handful of users upwards. | $15 / mo | hosted |
| 3 | [Calendly API + MCP](https://www.anchorterminal.com/tools/calendly.md) | B | 68.3 | Best when the host already schedules through Calendly and the agent needs to find a slot and book or cancel it. | $10 / seat-mo | hosted |
| 4 | [Microsoft Graph Calendar API](https://www.anchorterminal.com/tools/microsoft-graph-calendar.md) | B | 65.1 | Agents working inside Microsoft 365 tenants, especially when they need meeting-time suggestions across people and rooms. | Your plan | hosted |
| 5 | [Cronofy API](https://www.anchorterminal.com/tools/cronofy.md) | B | 64.2 | Products that schedule across many people and rooms with strict data residency, especially in the UK and EU. | $819 / mo | hosted |
| 6 | [Cal.com API v2 + MCP](https://www.anchorterminal.com/tools/cal-com.md) | C | 57.2 | An agent that books, reschedules and cancels meetings into a Cal.com user's event types, or routes leads with routing forms. | $12 / seat-mo | hosted and local |
| 7 | [Zoom Scheduler API](https://www.anchorterminal.com/tools/zoom-scheduler.md) | D | 50.6 | An agent booking into a Zoom Scheduler user's or team's booking pages, with slot lookup, booking, cancellation and two webhooks. | $5.99 / seat-mo | hosted |
| 8 | [Aurinko Calendar API](https://www.anchorterminal.com/tools/aurinko-calendar.md) | E | 45.6 | A product that connects many users' Google and Microsoft calendars and wants availability and booking at a low price per account. | Paid | hosted |
| 9 | [Acuity Scheduling API](https://www.anchorterminal.com/tools/acuity-scheduling.md) | E | 42.4 | A business that already takes bookings in Acuity and wants an agent to check slots, book, move and cancel appointments for clients, including classes, packages and intake forms. | $61 / mo | hosted |
| 10 | [Apiroc Unified Calendar API](https://www.anchorterminal.com/tools/apiroc.md) | E | 41.1 | A small product or an agent builder that needs read and write across Google, Microsoft and iCloud for tens to hundreds of accounts on a tight budget. | $25 / mo | hosted |

## Picks by need

- Highest score overall: [Google Calendar API](https://www.anchorterminal.com/tools/google-calendar-api.md), A, 80.6/100 on the benchmark. Also [Nylas Calendar and Scheduler API](https://www.anchorterminal.com/tools/nylas-calendar.md), BB, 71/100.
- Schema & documentation: [Nylas Calendar and Scheduler API](https://www.anchorterminal.com/tools/nylas-calendar.md), 91/100 on schema & documentation, against 83 for the overall leader.
- Maintenance & community: [Nylas Calendar and Scheduler API](https://www.anchorterminal.com/tools/nylas-calendar.md), 88/100 on maintenance & community, against 87 for the overall leader.

## How to choose

- Calendar services covered: Check which calendar services the API reads and writes, since an agent that must book across more than one service needs each one connected through the same integration.
- Time zones and availability logic: Test a slot that crosses a daylight saving change in several time zones, since wrong offsets can book a meeting at the wrong hour for an attendee.
- Webhook notifications and retries: Check how change notifications reach the agent and whether failed ones are retried, because an agent that misses a cancellation may keep treating a slot as taken.
- Cost for every account: Work out the bill for every account the agent will manage, since charges may apply to accounts that are only read.

- How the benchmark tests this category: An agent finds a free slot across a Google and a Microsoft calendar, books it, moves it and cancels it. We check availability accuracy, time zones, webhook delivery and the cost per connected account.

Each listing's verdict, strengths and weaknesses: https://www.anchorterminal.com/best/scheduling/index.md