Cal.com API v2 + MCP vs YouCanBookMe API

Cal.com API v2 + MCP 76

OpenAPI 3.0 document for API v2 (25). llms.txt and Markdown copies of reference pages (10). Reference pages explain each endpoint and parameter, but the hosted MCP's tool descriptions aren't public since the code went closed (12). Typed parameters with ranges, such as limit 1 to 100 with a default of 50 and enumerated booking statuses (12). Examples on reference pages. The response envelope has status success or error, but we found no error catalogue (8). Date-based cal-api-version per endpoint (2026-05-01 for bookings, 2024-09-04 for slots), and release notes come as blog posts rather than an API changelog (9).

YouCanBookMe API 10

The reference lives on Stoplight at ycbm.stoplight.io, which usually renders an OpenAPI file, but our reader got only the workspace shell, and no spec file was found at the usual paths; the help centre article on support.youcanbook.me sat behind a Cloudflare challenge. Scored absent (0 of 25). No llms.txt on youcanbook.me, the help centre or the Stoplight host (0). Descriptions, typed inputs and required fields unread (0 of 20, 0 of 15). The one response we saw is a JSON envelope with code, errors, httpCode, message and status, and the help centre gives a worked webhook payload (4 of 15). A /v1 path and x-api-version: 1.18 and x-api-revision headers, with a product updates page dated by month and no API changelog (6 of 15). 0 + 0 + 0 + 0 + 4 + 6 = 10.

Cal.com API v2 + MCP 60

OpenStatus page at status.cal.com with App, Website and API components and an events log back to February 2024 (20). In the last 90 days, a major API outage on 31 August (1 hour 14 minutes of HTTP 500s on /v2/slots and /v2/bookings in US East), a 1 hour 19 minute degradation of App and API on 15 September, and a partial outage of the Atoms endpoint on 21 July (10). 120 requests a minute per key or OAuth token, raisable to 200 and then to 800 on request (15). No 429 behaviour, rate-limit headers or retry guidance in the docs or the OpenAPI spec (0). Enterprise lists "SLA guarantees" with no published figure (5). API v2 is GA (10).

YouCanBookMe API 15

Read with the hosted lines. The help page links a status page at www.youcanbookmestatus.com, but the host did not resolve from our reader with or without www on 3 November 2026, so it is scored as not established rather than as a finding about the vendor (0). No readable history (5). No rate limit with a number in the help centre articles, the pricing page or the API's own error response; the API reference could not be read (0). No 429 or retry guidance and no idempotency key found (0). No SLA, and the terms say the service is not guaranteed to be available 100 per cent of the time (0). The API reports version 1.18 in its headers and is sold on the Team plan, so generally available (10). 0 + 5 + 0 + 0 + 0 + 10 = 15.

Cal.com API v2 + MCP 50

63 tools on the hosted MCP (5), with a toolsets query parameter to load only the groups you need and catalogue meta-tools (find, describe and call an API operation) (+10). Cursor pagination with limit, and filters on status, attendee, event type, team and start, end, created and updated times (20). Error envelope without documented codes (8). No idempotency key on bookings found, and we couldn't read the hosted tools for readOnlyHint or destructiveHint (0). No official REST SDK in two languages (Atoms is React components), and every endpoint needs the right version header (7).

YouCanBookMe API 13

Response sizing, field selection and pagination are in the unread reference (3 of 25, 0 of 20). The error envelope names a machine code and a message an agent can branch on (8 of 20). No idempotency key or safe-retry guidance found (0 of 20). No official SDK, and the required parameters are unread (2 of 15). 3 + 0 + 8 + 0 + 2 = 13.

Cal.com API v2 + MCP 56

OAuth with per-resource READ and WRITE scopes at user, team and organisation level, 30-minute access tokens, PKCE, and client secret rotation with two active secrets. OAuth clients are reviewed before use. API keys have test and live prefixes but no scopes (28). Read-only OAuth scopes and MCP toolsets narrow access, but nothing asks for confirmation before delete_event_type, cancel_booking or delete_org_membership (10). Bookings carry attendee-written names and notes into the model, with no injection guidance found (0). No operator request log found (0). ISO 27001, SOC 2 Type II and HIPAA claimed, an annual third-party penetration test, a Bugcrowd disclosure programme and a valid security.txt, though it points to the repository that now hosts the Cal.diy fork (18).

YouCanBookMe API 24

One account-wide API key sent as the HTTP Basic password with the account ID or email, generated and deleted by the Account Owner only; no scopes, expiry or per-user keys are documented (10 of 30). No read-only mode or confirmation step found (0 of 20). The API and webhooks carry names, answers and notes written by people who book, with no injection guidance (2 of 15). No audit log or per-call visibility found (0 of 15). SOC 2 Type II and ISO/IEC 27001:2022 (certificate 20/3433, 20 February 2024) and third-party penetration tests on the security page, but no security.txt (404), bug bounty or disclosure policy (12 of 20). 10 + 0 + 2 + 0 + 12 = 24.

Cal.com API v2 + MCP 50

v6.9 changelog post on 15 September 2026 (30). Only one dated changelog post found between June and September, so partial credit (5). Public blog changelog and support, no public issue tracker for the closed product (10). No current official REST SDKs, and the npm MCP package has sat at 0.0.6 since 22 May 2025 (5). The cal-mcp repository's test workflow has its test step commented out (0).

YouCanBookMe API 28

Read as a closed service. The newest product update is dated September 2026 (registered SMS numbers), within 90 days but not 30, taking the month's first day (20 of 30). The previous entry is November 2025, so fewer than three in 90 days (0 of 20). A help centre, a community forum at forum.youcanbook.me and one-to-one support for paid users, with a product updates page that carries no API items (8 of 15). No official SDKs found (0). No package to assess (0). 20 + 0 + 8 + 0 + 0 = 28.

Cal.com API v2 + MCP 78

Closed source since 14 April 2026, with terms that carry a 2021 effective date and name UK law for a San Francisco company. The security page still describes a self-hosted open-source option, which now means the Cal.diy community fork (12). Privacy policy (20 August 2026) says nothing is used to train models, account data is kept while active with a 30-day export window after closure, and logs exclude personal data. DPA in the compliance portal (22). Platform deprecation dated 15 December 2025 and date-pinned API versions (14). Subprocessors are listed in the trust centre per the privacy policy, which we didn't open, and data sits in the US with EU residency on request (13).

YouCanBookMe API 61

Closed service with terms (18 March 2026) naming AI Software (Capacity) UK Ltd under English law, which bar data-mining and robot tools without consent and let the company end membership without notice for a breach (15 of 30). The privacy notice (16 March 2026) states retention periods (24 months for booking data by default, 7 years for support messages), AWS hosting in the United States, a DPA on request and no training of external AI models on booking data; the security page says no subprocessor list is published, and the two agree on AWS (22 of 30). No deprecation policy or dated notice, and clause 18.4 allows changes to the service without notice (3 of 20). Providers are named in the privacy notice (AWS, Stripe, Google Analytics, Mixpanel, Hotjar, HubSpot) with US hosting, but there is no list with locations per processor (12 of 20). 15 + 22 + 3 + 12 = 52.