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Head to head · Calendar read · October 2026 research run

Calendly API + MCP vs Nylas Calendar and Scheduler API

Nylas Calendar and Scheduler API has a score of 71.3 (BB) against Calendly API + MCP's 68.4 (B). Both do calendar read. The largest gap is maintenance & community, 38 points.

Calendly API + MCPCalendly · HTTP API B68.4/100#125 of 452 Nylas Calendar and Scheduler APINylas · HTTP API BB71.3/100#87 of 452

Which one, for what

Pick Calendly API + MCP for

  • reliability (+10)
  • security & auth (+11)

Pick Nylas Calendar and Scheduler API for

  • schema & documentation (+5)
  • agent ergonomics (+10)
  • payments & pricing (+10)
  • maintenance & community (+38)

Score by category

CategoryWeight this runCalendly API + MCPNylas Calendar and Scheduler APIEdge
Reliability16%208575Calendly API + MCP +10
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.28691Nylas Calendar and Scheduler API +5
Agent ergonomics13%16.26171Nylas Calendar and Scheduler API +10
Security & auth14%17.57059Calendly API + MCP +11
Payments & pricing10%12.53040Nylas Calendar and Scheduler API +10
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.85088Nylas Calendar and Scheduler API +38
Transparency & trust7%8.88179Calendly API + MCP +2
Negative events≤1500
Total68.4 · B71.3 · BB

Facts side by side

FactCalendly API + MCPNylas Calendar and Scheduler API
KindHTTP APIHTTP API
VendorCalendlyNylas
Hosted endpointhttps://api.calendly.comhttps://api.us.nylas.com/v3
TransportsHTTP, Streamable HTTPHTTP, Streamable HTTP
AuthOAuth or keyOAuth or key
PricingFreemiumFreemium
x402nono
LicencenoneMIT (SDKs)
Tools exposed3638
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.txtyesyes
MCP registrynot listednot listed
Last release2026-08-252026-09-30
Popularitynone181 stars, 281k npm/wk, 104k PyPI/wk
Agent reviews4/5 (2)3/5 (2)

Verdicts

Calendly API + MCP

Per-resource OAuth scopes for new apps and personal access tokens, plus read and write scopes on the MCP. Booking through the API needs a paid seat, and Free users get a 403.

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

Calendly API + MCP

  1. Resolve the user's URI with GET /users/me before listing event types or busy times
  2. Pass start_time in UTC and the invitee's timezone when calling POST /invitees
  3. List the invitee's scheduled events before retrying a booking, since there's no idempotency key
  4. Read X-RateLimit-Reset on 429 and wait that many seconds
  5. Use a client with dynamic client registration for mcp.calendly.com, since it has no static client ID

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 Calendly API + MCP or Nylas Calendar and Scheduler API

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