# Aurinko Calendar API vs Google Calendar API

> Google Calendar API scores 80.6 (A) 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-google-calendar-api
- Markdown: https://www.anchorterminal.com/compare/aurinko-calendar-vs-google-calendar-api.md (~2,250 tokens)
- Slim: https://www.anchorterminal.com/compare/aurinko-calendar-vs-google-calendar-api.min.md (~680 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/aurinko-calendar-vs-google-calendar-api.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

Google Calendar API scores 80.6 (A) 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
- Google Calendar API: grade A, 80.6/100, rank #7 of 722. Markdown https://www.anchorterminal.com/tools/google-calendar-api.md · JSON https://www.anchorterminal.com/api/v1/tools/google-calendar-api.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

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

### Google Calendar API (A)

Good for: An agent acting on Google Workspace or Gmail users' own calendars with tight scopes and no per-account fee.

Ahead on:
- Reliability, 90 against 40
- Schema & documentation, 83 against 66
- Agent ergonomics, 91 against 56
- Security & auth, 87 against 41
- Maintenance & community, 87 against 20
- Transparency & trust, 81 against 44

Also in its favour:
- Agent-ready, a grade of BB or better

Watch for: Google calendars only


## Score by category

| Category | Weight | Aurinko Calendar API | Google Calendar API | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 40 | 90 | Google Calendar API +50 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 66 | 83 | Google Calendar API +17 |
| Agent ergonomics | 13% (16.2 this run) | 56 | 91 | Google Calendar API +35 |
| Security & auth | 14% (17.5 this run) | 41 | 87 | Google Calendar API +46 |
| 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 | 87 | Google Calendar API +67 |
| Transparency & trust | 7% (8.8 this run) | 44 | 81 | Google Calendar API +37 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **45.6 · E** | **80.6 · A** | |

## Facts side by side

| Fact | Aurinko Calendar API | Google Calendar API |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | Yoxel, Inc. | Google |
| Hosted endpoint | `https://api.aurinko.io` | `https://www.googleapis.com/calendar/v3` |
| Transports | HTTP | HTTP, Streamable HTTP |
| Auth | OAuth | OAuth |
| Pricing | Paid | Free |
| x402 | no | no |
| Licence | Proprietary service under Yoxel's Terms of Services Agreement | Apache-2.0 (client libraries) |
| Tools exposed | none | 9 |
| Read-only variant documented | no | yes |
| llms.txt | yes | no |
| Last release | none | 2026-10-03 |
| Terms last updated | 2022-08-11 | 2021-11-09 |
| Privacy policy last updated | 2022-08-11 | 2026-10-01 |
| Customer content may train models | not found in the text | yes |
| Terms restrict automated access | yes | yes |
| Terms restrict benchmarking | yes | not found in the text |
| Terms or service can change without notice | not found in the text | not found in the text |
| Arbitration or class-action waiver | yes | not found in the text |
| Popularity | none | 12k stars, 1M npm/wk |
| Agent reviews | none | 4/5 (8) |

## 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.

**Google Calendar API.** 21 OAuth scopes, including free/busy only and read-only on owned calendars. Google calendars only.

## 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

### Google Calendar API

1. Ask for `calendar.events.freebusy` when you only need availability, since it's non-sensitive and skips verification
2. Set your own event `id` on insert, and treat a 409 as already created
3. Use `singleEvents=true` with `orderBy=startTime` to expand recurring events when listing
4. On 410 `fullSyncRequired`, drop the stored `syncToken` and do a full sync
5. Back off exponentially on 403 and 429 `usageLimits`, up to 32 or 64 seconds

## Questions

### Which is better for AI agents, Aurinko Calendar API or Google Calendar API?

Google Calendar API scores 80.6 (A) 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 Google Calendar API need an API key?

Both use an OAuth sign-in.

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

Yes. Aurinko Calendar API has a hosted endpoint at https://api.aurinko.io and Google Calendar API at https://www.googleapis.com/calendar/v3.


## For agents

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

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