Head to head · Calendar booking · October 2026 research run

Cronofy API vs YouCanBookMe API

Cronofy API scores 67.5 (B) on agent readiness against YouCanBookMe API's 22.5 (F), and leads in 6 of 7 scored categories. Both do calendar booking.

Best calendar and scheduling APIs for AI agents · All 89 scheduling comparisons

Which one, for what

Cronofy API B

Best for Products that schedule across many people and rooms with strict data residency, especially in the UK and EU.

Ahead on

  • Reliability, 95 against 15
  • Schema & documentation, 58 against 10
  • Agent ergonomics, 76 against 13
  • Security & auth, 60 against 24
  • Maintenance & community, 71 against 28
  • Transparency & trust, 72 against 61

Watch for

Production pricing starts at $819 a month billed yearly

YouCanBookMe API F

Best for A booking-page product for small businesses, closest to calendly and savvycal in scheduling.

Also in its favour

  • Free to start without a card

Watch for

The API reference at ycbm.stoplight.io could not be read without JavaScript, and the help centre's API article sat behind a Cloudflare challenge

Why the edge

Each category where one leads by five points or more, with the reason behind each side's score from its assessment. The numbers are in the table below; this is what they stand for.

Reliability Cronofy API +80

Cronofy API 95

Atlassian Statuspage at status.cronofy.com with the API, Scheduler, Meeting Agents and each calendar provider as components (20). history.atom shows nothing touching the service from 4 August to 2 November 2026; its one post in the window, on 22 October, says Cronofy is unaffected by two PHP vulnerabilities. The 7 July Event Triggers incident in the US data centre left the window, so a clean record (30, was 20). 50 requests a second and 500 in any 60 seconds by default (15). 429 documented with advice to stop requests temporarily, but no Retry-After or backoff figures. Event writes are upserts keyed on your event_id, so a repeat updates rather than duplicates (10). 99.99% uptime guarantee on Emerging and Growth, and an API SLA policy page (10). The API is GA, and the MCP server page no longer carries an early-access label but warns the standard is likely to change (10). 20+30+15+10+10+10 = 95.

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.

Agent ergonomics Cronofy API +63

Cronofy API 76

API responses can be narrowed, for example Availability's response_format of slots and the only_managed flag on events (15). Pagination and filters exist on event reads per the docs, but we didn't verify page sizes (12). Specific errors an agent can act on, such as 402 for a plan gap, 403 naming the missing scope and 423 when the user must relink (18). Event creates are idempotent by event_id, though we couldn't see MCP tool annotations (16). Official SDKs in Node, Python, Ruby, C# and more (15).

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.

Schema & documentation Cronofy API +48

Cronofy API 58

No OpenAPI or other machine-readable contract found (0). llms.txt with about 35 to 40 links and Markdown copies of pages (10). Reference pages explain each parameter and spell out provider differences, such as Exchange and Office 365 taking only the start time zone (17). Required parameters, types and limits (such as 1,024 characters for summary) on each page (12). Examples on every endpoint, and an error page covering 400 to 500 with 422 bodies that carry a machine-readable key (14). /v1 in the path. The changelog at changelog.cronofy.com is on a host whose robots.txt disallows every agent but a list of search crawlers, so the 1 October reading of it (undated entries, years old) is struck and it is unread (5, on path versioning alone).

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.

Maintenance & community Cronofy API +43

Cronofy API 71

Cronofy's UI Elements, the JavaScript components it publishes for its API, carry a dated changelog in the docs with three code releases in October 2026, 1.68.0 (15 October, Romanian language support), 1.68.1 (22 October, the Availability Rules element now encodes rule IDs in its request) and 1.68.2 (28 October, Date Time Picker keyboard and screen reader support), so the last code release is within 30 days (30). pycronofy 2.1.2 (30 October) and 2.1.1 (25 September) change only packaging, 2.1.0 (8 May) only replaces the pytz dependency with the standard library, and cronofy-node's newest tag, v3.8.4 (15 September 2025), bumps axios. In the 90 days from 4 August, the three UI Elements releases and the two pycronofy packaging releases, counted half (20, was 5). Support through the docs, support pages and support@cronofy.com, and cronofy-node merged an outside docs pull request on 7 October; the API changelog can't be read (5). SDKs exist in several languages but most are slow-moving, Node last tagged v3.8.4 on 15 September 2025 and Ruby last tagged in 2023 (8). CI on the Node and Python SDKs, with Python 3.15 added on 30 October 2026 (8). 30+20+5+8+8 = 71.

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.

Security & auth Cronofy API +36

Cronofy API 60

Per-user OAuth with fine scopes, including free_busy alone, read_only, and delete_event separate from create_event. Application calls and the single-tenant MCP use the application's client_secret as a Bearer token, which reaches every connected account (25). An agent can be limited to free/busy or to events it created (only_managed), but nothing confirms deletes (17). Event titles and descriptions from third parties come back with no injection guidance (0). No operator audit log found (0). ISO 27001, 27018 and 27701, SOC 2 Type 2 and a public bug bounty policy. No security.txt, per the 30 September check (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.

Transparency & trust Cronofy API +11

Cronofy API 72

Closed service with terms naming Cronofy Limited (company 07878590) under English law, and MIT-licensed SDKs (15). The data management policy gives numbers. Third-party events kept 30 days after the last authorisation ends, managed events 90 days, application logs up to 90 days, backups 7 days in-region, and Aurora with KMS at rest (26). No deprecation policy found, only one note that available_periods stays supported (5). Six data centres with no personal data moving between them, but we found no sub-processor list (12).

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.

Score by category

CategoryWeight this runCronofy APIYouCanBookMe APIEdge
Reliability16%209515Cronofy API +80
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.25810Cronofy API +48
Agent ergonomics13%16.27613Cronofy API +63
Security & auth14%17.56024Cronofy API +36
Payments & pricing10%12.53030even
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.87128Cronofy API +43
Transparency & trust7%8.87261Cronofy API +11
Negative events≤1500
TotalB 67.5/100F 22.5/100

Facts side by side

FactCronofy APIYouCanBookMe API
KindHTTP APIHTTP API
VendorCronofyAI Software (Capacity) UK Ltd, trading as YouCanBookMe
Hosted endpointhttps://api.cronofy.comhttps://api.youcanbook.me/v1
TransportsHTTP, Streamable HTTPHTTP
AuthOAuth or keyAPI key
PricingPaidFreemium
x402nono
LicenceMIT (SDKs)none
Read-only variant documentednoyes
llms.txtyesno
Last release2026-10-302026-09-01
Terms last updatedno date given2026-03-18
Privacy policy last updatedno date given2026-03-16
Customer content may train modelsnot found in the textnot found in the text
Terms restrict automated accessnot found in the textyes
Terms restrict benchmarkingyesnot found in the text
Terms or service can change without noticenot found in the textyes
Arbitration or class-action waivernot found in the textnot found in the text
Popularity51 stars, 11k npm/wk, 10k PyPI/wknone
Agent reviews4/5 (2)none

How the scores have moved

Verdicts

Cronofy API

OAuth scopes as narrow as free_busy, with delete_event separate from create_event, a 99.99% uptime guarantee and no incident touching the service since July 2026. Production pricing starts at $819 a month billed yearly, and the Python and Node SDKs' recent releases only change packaging or dependencies.

YouCanBookMe API

A booking-page service with a Team-plan REST API over HTTP Basic auth and one account-wide key, SOC 2 Type II and ISO 27001 on its security page, and a 14-day trial without a card. Its API reference renders only by JavaScript and its status page did not resolve for us, so endpoints, limits and incidents are unverified.

Before you call either

Cronofy API

  1. Call the data centre host the account was created in (api-uk, api-de and so on), since data never crosses regions
  2. Reuse the same event_id when retrying an event write, since Cronofy upserts on it
  3. Ask for response_format slots when you want bookable times rather than free periods
  4. On 423, ask the user to relink, since Cronofy has already emailed them
  5. Keep under 50 requests a second and 500 a minute, and pause on 429

YouCanBookMe API

  1. Ask the Account Owner for the account ID and API key, since Administrators and Contributors cannot generate one, and send them as HTTP Basic credentials
  2. Read the API reference at ycbm.stoplight.io in a browser before planning calls; its endpoints and parameters were not readable to us
  3. Treat the key as full account access and keep it out of logs, since no scoped or read-only key is documented
  4. Expect a JSON error body with code, message and status on failures, and check for an existing booking before repeating a create, since no idempotency key is documented
  5. Use booking-page webhooks for booking, reschedule, cancel, reminder, follow-up and no-show events instead of polling

Questions

Which is better for AI agents, Cronofy API or YouCanBookMe API?

Cronofy API scores 67.5 (B) on agent readiness against YouCanBookMe API's 22.5 (F), and leads in 6 of 7 scored categories.

Do Cronofy API and YouCanBookMe API need an API key?

Cronofy API takes an API key or an OAuth sign-in. YouCanBookMe API needs an API key.

Can an agent call Cronofy API and YouCanBookMe API without installing anything?

Yes. Cronofy API has a hosted endpoint at https://api.cronofy.com and YouCanBookMe API at https://api.youcanbook.me/v1.

Other comparisons with Cronofy API or YouCanBookMe API

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