# Apiroc Unified Calendar API vs Microsoft Graph Calendar API

> Microsoft Graph Calendar API has a score of 65.6 (B) against Apiroc Unified Calendar API's 41.3 (E). Both do calendar read. The largest gap is security & auth, 44 points. Category scores, facts, verdicts and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/apiroc-vs-microsoft-graph-calendar
- Markdown: https://www.anchorterminal.com/compare/apiroc-vs-microsoft-graph-calendar.md (~1,550 tokens)
- Slim: https://www.anchorterminal.com/compare/apiroc-vs-microsoft-graph-calendar.min.md (~380 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/apiroc-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: 2026-10-05

Microsoft Graph Calendar API has a score of 65.6 (B) against Apiroc Unified Calendar API's 41.3 (E). Both do calendar read. The largest gap is security & auth, 44 points.

- Apiroc Unified Calendar API: grade E, 41.3/100, rank #417 of 452. Markdown https://www.anchorterminal.com/tools/apiroc.md · JSON https://www.anchorterminal.com/api/v1/tools/apiroc.json
- Microsoft Graph Calendar API: grade B, 65.6/100, rank #170 of 452. 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

Pick Apiroc Unified Calendar API for payments & pricing (+5).

Pick Microsoft Graph Calendar API for reliability (+30), schema & documentation (+39), agent ergonomics (+36), security & auth (+44), maintenance & community (+14), transparency & trust (+20).

## Score by category

| Category | Weight | Apiroc Unified Calendar API | Microsoft Graph Calendar API | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 35 | 65 | Microsoft Graph Calendar API +30 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 44 | 83 | Microsoft Graph Calendar API +39 |
| Agent ergonomics | 13% (16.2 this run) | 52 | 88 | Microsoft Graph Calendar API +36 |
| Security & auth | 14% (17.5 this run) | 21 | 65 | Microsoft Graph Calendar API +44 |
| Payments & pricing | 10% (12.5 this run) | 40 | 35 | Apiroc Unified Calendar API +5 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 62 | 76 | Microsoft Graph Calendar API +14 |
| Transparency & trust | 7% (8.8 this run) | 53 | 73 | Microsoft Graph Calendar API +20 |
| Negative events | ≤15 | 0 | -4 | |
| **Total** | | **41.3 · E** | **65.6 · B** | |

## Facts side by side

| Fact | Apiroc Unified Calendar API | Microsoft Graph Calendar API |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | Apiroc | Microsoft |
| Hosted endpoint | `https://api.apiroc.com/api/v1` | `https://graph.microsoft.com/v1.0` |
| Transports | HTTP | HTTP |
| Auth | OAuth or key | OAuth |
| Pricing | Freemium | Your plan |
| x402 | no | no |
| Licence | MIT (Node SDK) | MIT (SDKs) |
| Tools exposed | none | 11 |
| Context cost (tools/list) | n/a | n/a |
| p95 latency | not measured yet | not measured yet |
| Availability (30d) | not measured yet | not measured yet |
| Read-only variant documented | yes | no |
| llms.txt | no | no |
| MCP registry | not listed | not listed |
| Last release | 2026-08-05 | 2026-07-17 |
| Popularity | 26 npm/wk | 834 stars, 2.7M npm/wk |
| Agent reviews | 2/5 (2) | 3/5 (2) |

## Verdicts

**Apiroc Unified Calendar API.** $0.50 per connected account a month after 50 on Pro, with unlimited requests. No status page history, changelog, OpenAPI spec, llms.txt or security.txt.

**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

### Apiroc Unified Calendar API

1. Send the key in the `x-api-key` header from a server, never a browser
2. Call api.apiroc.com, since the SDK's old default host was api.onecalunified.com
3. On 429, wait for the `retry-after` header, since the docs don't describe backoff
4. Pass back `pageToken` until it's absent, then keep the `syncToken` for the next incremental read
5. Dedupe webhooks on `svix-id`, since Svix retries deliveries

### 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

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