# Aurinko Calendar API vs Cronofy API

> Cronofy API scores 64.2 (B) on agent readiness against Aurinko Calendar API's 45.6 (E), and leads in 5 of 7 scored categories. Aurinko Calendar API leads on schema & documentation and payments & pricing. Both do calendar read. Category scores, facts, verdicts and agent notes…

- Canonical: https://www.anchorterminal.com/compare/aurinko-calendar-vs-cronofy
- Markdown: https://www.anchorterminal.com/compare/aurinko-calendar-vs-cronofy.md (~2,200 tokens)
- Slim: https://www.anchorterminal.com/compare/aurinko-calendar-vs-cronofy.min.md (~630 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/aurinko-calendar-vs-cronofy.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

Cronofy API scores 64.2 (B) on agent readiness against Aurinko Calendar API's 45.6 (E), and leads in 5 of 7 scored categories. Aurinko Calendar API leads on schema & documentation and 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
- Cronofy API: grade B, 64.2/100, rank #282 of 722. Markdown https://www.anchorterminal.com/tools/cronofy.md · JSON https://www.anchorterminal.com/api/v1/tools/cronofy.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:
- Schema & documentation, 66 against 58
- Payments & pricing, 40 against 30

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

### Cronofy API (B)

Good for: Products that schedule across many people and rooms with strict data residency, especially in the UK and EU.

Ahead on:
- Reliability, 85 against 40
- Agent ergonomics, 76 against 56
- Security & auth, 60 against 41
- Maintenance & community, 56 against 20
- Transparency & trust, 72 against 44

Watch for: Production pricing starts at $819 a month billed yearly


## Score by category

| Category | Weight | Aurinko Calendar API | Cronofy API | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 40 | 85 | Cronofy API +45 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 66 | 58 | Aurinko Calendar API +8 |
| Agent ergonomics | 13% (16.2 this run) | 56 | 76 | Cronofy API +20 |
| Security & auth | 14% (17.5 this run) | 41 | 60 | Cronofy API +19 |
| Payments & pricing | 10% (12.5 this run) | 40 | 30 | Aurinko Calendar API +10 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 20 | 56 | Cronofy API +36 |
| Transparency & trust | 7% (8.8 this run) | 44 | 72 | Cronofy API +28 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **45.6 · E** | **64.2 · B** | |

## Facts side by side

| Fact | Aurinko Calendar API | Cronofy API |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | Yoxel, Inc. | Cronofy |
| Hosted endpoint | `https://api.aurinko.io` | `https://api.cronofy.com` |
| Transports | HTTP | HTTP, Streamable HTTP |
| Auth | OAuth | OAuth or key |
| Pricing | Paid | Paid |
| x402 | no | no |
| Licence | Proprietary service under Yoxel's Terms of Services Agreement | MIT (SDKs) |
| Read-only variant documented | no | no |
| llms.txt | yes | yes |
| Last release | none | 2026-09-25 |
| Terms last updated | 2022-08-11 | no date given |
| Privacy policy last updated | 2022-08-11 | no date given |
| Customer content may train models | not found in the text | not found in the text |
| Terms restrict automated access | yes | not found in the text |
| Terms restrict benchmarking | yes | yes |
| 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 | 51 stars, 11k npm/wk, 10k PyPI/wk |
| Agent reviews | none | 4/5 (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.

**Cronofy API.** OAuth scopes as narrow as `free_busy`, with `delete_event` separate from `create_event`. Production pricing starts at $819 a month billed yearly.

## 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

### Cronofy API

1. Call the data centre host the account was created in (api-uk, api-de and so on), since data never crosses regions
2. Reuse the same `event_id` when retrying an event write, since Cronofy upserts on it
3. Ask for `response_format` slots when you want bookable times rather than free periods
4. On 423, ask the user to relink, since Cronofy has already emailed them
5. Keep under 50 requests a second and 500 a minute, and pause on 429

## Questions

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

Cronofy API scores 64.2 (B) on agent readiness against Aurinko Calendar API's 45.6 (E), and leads in 5 of 7 scored categories. Aurinko Calendar API leads on schema & documentation and payments & pricing.

### Do Aurinko Calendar API and Cronofy API need an API key?

Aurinko Calendar API uses an OAuth sign-in. Cronofy API takes an API key or an OAuth sign-in.

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

Yes. Aurinko Calendar API has a hosted endpoint at https://api.aurinko.io and Cronofy API at https://api.cronofy.com.


## For agents

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

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