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Head to head · Calendar read · October 2026 research run

Microsoft Graph Calendar API vs Nylas Calendar and Scheduler API

Nylas Calendar and Scheduler API has a score of 71.3 (BB) against Microsoft Graph Calendar API's 65.6 (B). Both do calendar read. The largest gap is agent ergonomics, 17 points.

Microsoft Graph Calendar APIMicrosoft · HTTP API B65.6/100#170 of 452 Nylas Calendar and Scheduler APINylas · HTTP API BB71.3/100#87 of 452

Which one, for what

Pick Microsoft Graph Calendar API for

  • agent ergonomics (+17)
  • security & auth (+6)

Pick Nylas Calendar and Scheduler API for

  • reliability (+10)
  • schema & documentation (+8)
  • payments & pricing (+5)
  • maintenance & community (+12)
  • transparency & trust (+6)

Score by category

CategoryWeight this runMicrosoft Graph Calendar APINylas Calendar and Scheduler APIEdge
Reliability16%206575Nylas Calendar and Scheduler API +10
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.28391Nylas Calendar and Scheduler API +8
Agent ergonomics13%16.28871Microsoft Graph Calendar API +17
Security & auth14%17.56559Microsoft Graph Calendar API +6
Payments & pricing10%12.53540Nylas Calendar and Scheduler API +5
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.87688Nylas Calendar and Scheduler API +12
Transparency & trust7%8.87379Nylas Calendar and Scheduler API +6
Negative events≤15-40
Total65.6 · B71.3 · BB

Facts side by side

FactMicrosoft Graph Calendar APINylas Calendar and Scheduler API
KindHTTP APIHTTP API
VendorMicrosoftNylas
Hosted endpointhttps://graph.microsoft.com/v1.0https://api.us.nylas.com/v3
TransportsHTTPHTTP, Streamable HTTP
AuthOAuthOAuth or key
PricingYour planFreemium
x402nono
LicenceMIT (SDKs)MIT (SDKs)
Tools exposed1138
Context cost (tools/list)n/an/a
p95 latencynot measured yetnot measured yet
Availability (30d)not measured yetnot measured yet
Read-only variant documentednono
llms.txtnoyes
MCP registrynot listednot listed
Last release2026-07-172026-09-30
Popularity834 stars, 2.7M npm/wk181 stars, 281k npm/wk, 104k PyPI/wk
Agent reviews3/5 (2)3/5 (2)

Verdicts

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.

Nylas Calendar and Scheduler API

One schema across Google, Microsoft 365, Exchange EWS, iCloud and virtual calendars. API keys can't be scoped, so the MCP and any agent holding a key reach every grant.

Before you call either

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

Nylas Calendar and Scheduler API

  1. Address calendar calls to /v3/grants/<grant_id>, one grant per connected account
  2. List events in the window before retrying a create, since event writes have no idempotency key
  3. Point the MCP client at mcp.eu.nylas.com if the application lives in the EU region
  4. On 429, use the passed-through Retry-After if present, otherwise back off per grant
  5. Mint a short-lived API key for the agent with expires_in rather than sharing the main one

Other comparisons with Microsoft Graph Calendar API or Nylas Calendar and Scheduler API

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