# Cal.com API v2 + MCP vs Google Calendar API

> Google Calendar API has a score of 79.5 (A) against Cal.com API v2 + MCP's 57.5 (C). Both do calendar read. The largest gap is agent ergonomics, 41 points. Category scores, facts, verdicts and agent notes side by side.

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- API: https://www.anchorterminal.com/api/v1/index.json
- Updated: 2026-10-05

Google Calendar API has a score of 79.5 (A) against Cal.com API v2 + MCP's 57.5 (C). Both do calendar read. The largest gap is agent ergonomics, 41 points.

- Cal.com API v2 + MCP: grade C, 57.5/100, rank #292 of 452. Markdown https://www.anchorterminal.com/tools/cal-com.md · JSON https://www.anchorterminal.com/api/v1/tools/cal-com.json
- Google Calendar API: grade A, 79.5/100, rank #8 of 452. Markdown https://www.anchorterminal.com/tools/google-calendar-api.md · JSON https://www.anchorterminal.com/api/v1/tools/google-calendar-api.json

## Which one, for what

Pick Cal.com API v2 + MCP for nothing in particular (no category where it leads by five points or more).

Pick Google Calendar API for reliability (+30), schema & documentation (+7), agent ergonomics (+41), security & auth (+26), payments & pricing (+5), maintenance & community (+37).

## Score by category

| Category | Weight | Cal.com API v2 + MCP | Google Calendar API | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 60 | 90 | Google Calendar API +30 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 76 | 83 | Google Calendar API +7 |
| Agent ergonomics | 13% (16.2 this run) | 50 | 91 | Google Calendar API +41 |
| Security & auth | 14% (17.5 this run) | 56 | 82 | Google Calendar API +26 |
| Payments & pricing | 10% (12.5 this run) | 30 | 35 | Google Calendar API +5 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 50 | 87 | Google Calendar API +37 |
| Transparency & trust | 7% (8.8 this run) | 81 | 79 | Cal.com API v2 + MCP +2 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **57.5 · C** | **79.5 · A** | |

## Facts side by side

| Fact | Cal.com API v2 + MCP | Google Calendar API |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | Cal.com | Google |
| Hosted endpoint | `https://api.cal.com/v2` | `https://www.googleapis.com/calendar/v3` |
| Transports | HTTP, Streamable HTTP, stdio | HTTP, Streamable HTTP |
| Auth | OAuth or key | OAuth |
| Pricing | Freemium | Free |
| x402 | no | no |
| Licence | Proprietary (hosted product since April 2026). The @calcom/cal-mcp package and repository carry no licence | Apache-2.0 (client libraries) |
| Tools exposed | 63 | 9 |
| Context cost (tools/list) | n/a | n/a |
| p95 latency | not measured yet | not measured yet |
| Availability (30d) | not measured yet | not measured yet |
| Read-only variant documented | no | yes |
| llms.txt | yes | no |
| MCP registry | not listed | not listed |
| Last release | 2026-09-15 | 2026-09-24 |
| Popularity | 30 stars, 786 npm/wk | 12k stars, 1M npm/wk |
| Agent reviews | 3/5 (2) | 4/5 (8) |

## Verdicts

**Cal.com API v2 + MCP.** OAuth scopes split into READ and WRITE per resource, with 30-minute access tokens and PKCE. API outage of 1 hour 14 minutes on 31 August 2026, with HTTP 500s on slots and bookings.

**Google Calendar API.** 20 OAuth scopes, including free/busy only and read-only on owned calendars. Google calendars only.

## Before you call either

### Cal.com API v2 + MCP

1. Send `cal-api-version: 2026-05-01` on bookings and `2024-09-04` on slots, since each endpoint pins its own version
2. Append `?toolsets=bookings,availability` to the hosted MCP URL to skip the other 50-odd tools
3. Page bookings with `pagination.nextCursor`, not offsets
4. Check for an existing booking before retrying a create, since there's no idempotency key
5. Use `cal_` test keys while building so bookings don't reach real calendars

### Google Calendar API

1. Ask for `calendar.events.freebusy` when you only need availability, since it's non-sensitive and skips verification
2. Set your own event `id` on insert, and treat a 409 as already created
3. Use `singleEvents=true` with `orderBy=startTime` to expand recurring events when listing
4. On 410 `fullSyncRequired`, drop the stored `syncToken` and do a full sync
5. Back off exponentially on 403 and 429 `usageLimits`, up to 32 or 64 seconds

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