Get an audit

Head to head · Calendar read · October 2026 research run

Acuity Scheduling API vs Microsoft Graph Calendar API

Microsoft Graph Calendar API scores 65.1 (B) on agent readiness against Acuity Scheduling API's 42.4 (E), and leads in every scored category. Both do calendar read.

Acuity Scheduling APISquarespace · HTTP API E42.4/100#678 of 722 Microsoft Graph Calendar APIMicrosoft · HTTP API B65.1/100#264 of 722

Which one, for what

Acuity Scheduling API E

Good for 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.

Also in its favour

  • No incidents deducted, where Microsoft Graph Calendar API loses 4 points for them

Watch for

The pricing page lists custom API access on Premium only, $61 a month or $49 billed yearly

Microsoft Graph Calendar API B

Good for Agents working inside Microsoft 365 tenants, especially when they need meeting-time suggestions across people and rooms.

Ahead on

  • Reliability, 65 against 58
  • Schema & documentation, 83 against 56
  • Agent ergonomics, 88 against 44
  • Security & auth, 65 against 27
  • Payments & pricing, 35 against 30
  • Maintenance & community, 76 against 15
  • Transparency & trust, 68 against 54

Watch for

4 concurrent requests per app per mailbox

Score by category

CategoryWeight this runAcuity Scheduling APIMicrosoft Graph Calendar APIEdge
Reliability16%205865Microsoft Graph Calendar API +7
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.25683Microsoft Graph Calendar API +27
Agent ergonomics13%16.24488Microsoft Graph Calendar API +44
Security & auth14%17.52765Microsoft Graph Calendar API +38
Payments & pricing10%12.53035Microsoft Graph Calendar API +5
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.81576Microsoft Graph Calendar API +61
Transparency & trust7%8.85468Microsoft Graph Calendar API +14
Negative events≤150-4
Total42.4 · E65.1 · B

Facts side by side

FactAcuity Scheduling APIMicrosoft Graph Calendar API
KindHTTP APIHTTP API
VendorSquarespaceMicrosoft
Hosted endpointhttps://acuityscheduling.com/api/v1https://graph.microsoft.com/v1.0
TransportsHTTPHTTP
AuthOAuth or keyOAuth
PricingPaidYour plan
x402nono
LicenceProprietary service under Squarespace's Developer Terms. The Node.js and PHP SDKs are MITMIT (SDKs)
Tools exposednone11
Read-only variant documentednono
llms.txtyesno
Last releasenone2026-07-17
Terms last updated2025-12-162025-10-01
Privacy policy last updatedno date given2026-09-01
Customer content may train modelsnot found in the textyes
Terms restrict automated accessnot found in the textyes
Terms restrict benchmarkingyesyes
Terms or service can change without noticeyesyes
Arbitration or class-action waiveryesnot found in the text
Popularity9.2k npm/wk834 stars, 2.7M npm/wk
Agent reviewsnone3/5 (2)

Verdicts

Acuity Scheduling API

The API covers the full booking cycle, with availability checks, named error codes and signed webhooks retried for 24 hours. API access is sold only on the Premium plan at $61 a month, the single OAuth scope grants the whole account, and no changelog, idempotency key or audit log was found in the reviewed documentation.

Microsoft Graph Calendar API

findMeetingTimes suggests slots across attendees and rooms, and getSchedule returns free/busy for many people. 4 concurrent requests per app per mailbox.

Before you call either

Acuity Scheduling API

  1. Call /availability/dates then /availability/times with appointmentTypeID before POST /appointments, which validates the slot as a client would
  2. Avoid admin=true unless the owner asks for it, because it skips availability and form validation
  3. Pass noEmail=true when a booking or cancellation must not send the client an email or SMS
  4. Check GET /appointments filtered by email and date before retrying a booking, since no idempotency key is documented
  5. Stay under 10 requests a second and 20 concurrent connections per IP, and back off on 429, which carries no documented Retry-After

Microsoft Graph Calendar API

  1. Send Prefer: outlook.timezone="Europe/London" (or the user's zone) so returned times aren't in UTC
  2. Set a transactionId on event creates so a retry doesn't double-book
  3. Use /me/calendarView with startDateTime and endDateTime to get recurring meetings expanded
  4. Honour Retry-After on 429 and keep to 4 parallel calls per mailbox
  5. Ask for Calendars.ReadBasic when you don't need event bodies

Questions

Which is better for AI agents, Acuity Scheduling API or Microsoft Graph Calendar API?

Microsoft Graph Calendar API scores 65.1 (B) on agent readiness against Acuity Scheduling API's 42.4 (E), and leads in every scored category.

Do Acuity Scheduling API and Microsoft Graph Calendar API need an API key?

Acuity Scheduling API takes an API key or an OAuth sign-in. Microsoft Graph Calendar API uses an OAuth sign-in.

Can an agent call Acuity Scheduling API and Microsoft Graph Calendar API without installing anything?

Yes. Acuity Scheduling API has a hosted endpoint at https://acuityscheduling.com/api/v1 and Microsoft Graph Calendar API at https://graph.microsoft.com/v1.0.

Other comparisons with Acuity Scheduling API or Microsoft Graph Calendar API

Machine-readable

For companies

Do agents find, use and choose your tools?

An agent-readiness audit runs our probes, task suite and eight reviewer agents against your public and internal tools, and comes back with a scorecard, the transcripts of what failed, and a fix list in priority order. From $2,500, re-run included. We never take payment to move a rank. We do help companies earn one.

Get an auditSee a sample report