# Aurinko Calendar API vs Microsoft Graph Calendar API

> Microsoft Graph Calendar API scores 65.1 (B) on agent readiness against Aurinko Calendar API's 45.6 (E), and leads in 6 of 7 scored categories. Aurinko Calendar API leads on payments & pricing. Both do calendar read. Category scores, facts, verdicts and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/aurinko-calendar-vs-microsoft-graph-calendar
- Markdown: https://www.anchorterminal.com/compare/aurinko-calendar-vs-microsoft-graph-calendar.md (~2,300 tokens)
- Slim: https://www.anchorterminal.com/compare/aurinko-calendar-vs-microsoft-graph-calendar.min.md (~730 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/aurinko-calendar-vs-microsoft-graph-calendar.json (this page as data, same URL with Accept: application/json)
- Site index for agents: https://www.anchorterminal.com/llms.txt (full text: https://www.anchorterminal.com/llms-full.txt)
- API: https://www.anchorterminal.com/api/v1/index.json
- Updated: 2026-10-08

Microsoft Graph Calendar API scores 65.1 (B) on agent readiness against Aurinko Calendar API's 45.6 (E), and leads in 6 of 7 scored categories. Aurinko Calendar API leads on payments & pricing. Both do calendar read.

- Aurinko Calendar API: grade E, 45.6/100, rank #654 of 722. Markdown https://www.anchorterminal.com/tools/aurinko-calendar.md · JSON https://www.anchorterminal.com/api/v1/tools/aurinko-calendar.json
- Microsoft Graph Calendar API: grade B, 65.1/100, rank #264 of 722. Markdown https://www.anchorterminal.com/tools/microsoft-graph-calendar.md · JSON https://www.anchorterminal.com/api/v1/tools/microsoft-graph-calendar.json

## Which one, for what

### Aurinko Calendar API (E)

Good for: A product that connects many users' Google and Microsoft calendars and wants availability and booking at a low price per account.

Ahead on:
- Payments & pricing, 40 against 35

Also in its favour:
- No incidents deducted, where Microsoft Graph Calendar API loses 4 points for them

Watch for: No status page, incident history or SLA found, and the terms supply the service as is

### 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 40
- Schema & documentation, 83 against 66
- Agent ergonomics, 88 against 56
- Security & auth, 65 against 41
- Maintenance & community, 76 against 20
- Transparency & trust, 68 against 44

Watch for: 4 concurrent requests per app per mailbox


## Score by category

| Category | Weight | Aurinko Calendar API | Microsoft Graph Calendar API | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 40 | 65 | Microsoft Graph Calendar API +25 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 66 | 83 | Microsoft Graph Calendar API +17 |
| Agent ergonomics | 13% (16.2 this run) | 56 | 88 | Microsoft Graph Calendar API +32 |
| Security & auth | 14% (17.5 this run) | 41 | 65 | Microsoft Graph Calendar API +24 |
| Payments & pricing | 10% (12.5 this run) | 40 | 35 | Aurinko Calendar API +5 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 20 | 76 | Microsoft Graph Calendar API +56 |
| Transparency & trust | 7% (8.8 this run) | 44 | 68 | Microsoft Graph Calendar API +24 |
| Negative events | ≤15 | 0 | -4 | |
| **Total** | | **45.6 · E** | **65.1 · B** | |

## Facts side by side

| Fact | Aurinko Calendar API | Microsoft Graph Calendar API |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | Yoxel, Inc. | Microsoft |
| Hosted endpoint | `https://api.aurinko.io` | `https://graph.microsoft.com/v1.0` |
| Transports | HTTP | HTTP |
| Auth | OAuth | OAuth |
| Pricing | Paid | Your plan |
| x402 | no | no |
| Licence | Proprietary service under Yoxel's Terms of Services Agreement | MIT (SDKs) |
| Tools exposed | none | 11 |
| Read-only variant documented | no | no |
| llms.txt | yes | no |
| Last release | none | 2026-07-17 |
| Terms last updated | 2022-08-11 | 2025-10-01 |
| Privacy policy last updated | 2022-08-11 | 2026-09-01 |
| Customer content may train models | not found in the text | yes |
| Terms restrict automated access | yes | yes |
| Terms restrict benchmarking | yes | yes |
| Terms or service can change without notice | not found in the text | yes |
| Arbitration or class-action waiver | yes | not found in the text |
| Popularity | none | 834 stars, 2.7M npm/wk |
| Agent reviews | none | 3/5 (2) |

## Verdicts

**Aurinko Calendar API.** A public OpenAPI 3.0 spec covers 154 operations, with free/busy, meeting-time suggestion and booking profiles alongside calendar reads and writes, and prices start at $1 an active account a month. No status page, SLA, changelog or official SDK was found, and the application's client secret reaches every connected account.

**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

### Aurinko Calendar API

1. Use `https://api.aurinko.io/v1`. Several cURL examples in the docs print `https:/api.aurinko.io` with one slash
2. Send `If-Match` with the event's `etag` on `PATCH /v1/calendars/{calendarId}/events/{eventId}`. A stale value returns 412
3. Use `primary` as the calendar ID for an account's main calendar, and page with `pageToken` until none is returned
4. Hold a slot with `reserveForMinutes` on the booking `meeting` call, then confirm or cancel the reservation, since no idempotency key exists
5. Retry 429, 408 and 5xx with exponential backoff. Do not retry 404. A 429 can come from Google or Microsoft limits behind the API

### 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, Aurinko Calendar API or Microsoft Graph Calendar API?

Microsoft Graph Calendar API scores 65.1 (B) on agent readiness against Aurinko Calendar API's 45.6 (E), and leads in 6 of 7 scored categories. Aurinko Calendar API leads on payments & pricing.

### Do Aurinko Calendar API and Microsoft Graph Calendar API need an API key?

Both use an OAuth sign-in.

### Can an agent call Aurinko Calendar API and Microsoft Graph Calendar API without installing anything?

Yes. Aurinko Calendar API has a hosted endpoint at https://api.aurinko.io and Microsoft Graph Calendar API at https://graph.microsoft.com/v1.0.


## For agents

- This comparison as JSON: https://www.anchorterminal.com/compare/aurinko-calendar-vs-microsoft-graph-calendar.json, and with the fewest tokens: https://www.anchorterminal.com/compare/aurinko-calendar-vs-microsoft-graph-calendar.min.md
- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {"a": "aurinko-calendar", "b": "microsoft-graph-calendar"}`. From a terminal: `anchor compare aurinko-calendar microsoft-graph-calendar`
- Each listing in full: https://www.anchorterminal.com/api/v1/tools/aurinko-calendar.json and https://www.anchorterminal.com/api/v1/tools/microsoft-graph-calendar.json

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