# Apiroc Unified Calendar API vs Calendly API + MCP

> Calendly API + MCP has a score of 68.4 (B) against Apiroc Unified Calendar API's 41.3 (E). Both do calendar read. The largest gap is reliability, 50 points. Category scores, facts, verdicts and agent notes side by side.

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- API: https://www.anchorterminal.com/api/v1/index.json
- Updated: 2026-10-05

Calendly API + MCP has a score of 68.4 (B) against Apiroc Unified Calendar API's 41.3 (E). Both do calendar read. The largest gap is reliability, 50 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
- Calendly API + MCP: grade B, 68.4/100, rank #125 of 452. Markdown https://www.anchorterminal.com/tools/calendly.md · JSON https://www.anchorterminal.com/api/v1/tools/calendly.json

## Which one, for what

Pick Apiroc Unified Calendar API for payments & pricing (+10), maintenance & community (+12).

Pick Calendly API + MCP for reliability (+50), schema & documentation (+42), agent ergonomics (+9), security & auth (+49), transparency & trust (+28).

## Score by category

| Category | Weight | Apiroc Unified Calendar API | Calendly API + MCP | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 35 | 85 | Calendly API + MCP +50 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 44 | 86 | Calendly API + MCP +42 |
| Agent ergonomics | 13% (16.2 this run) | 52 | 61 | Calendly API + MCP +9 |
| Security & auth | 14% (17.5 this run) | 21 | 70 | Calendly API + MCP +49 |
| Payments & pricing | 10% (12.5 this run) | 40 | 30 | Apiroc Unified Calendar API +10 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 62 | 50 | Apiroc Unified Calendar API +12 |
| Transparency & trust | 7% (8.8 this run) | 53 | 81 | Calendly API + MCP +28 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **41.3 · E** | **68.4 · B** | |

## Facts side by side

| Fact | Apiroc Unified Calendar API | Calendly API + MCP |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | Apiroc | Calendly |
| Hosted endpoint | `https://api.apiroc.com/api/v1` | `https://api.calendly.com` |
| Transports | HTTP | HTTP, Streamable HTTP |
| Auth | OAuth or key | OAuth or key |
| Pricing | Freemium | Freemium |
| x402 | no | no |
| Licence | MIT (Node SDK) | none |
| Tools exposed | none | 36 |
| 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 | yes |
| MCP registry | not listed | not listed |
| Last release | 2026-08-05 | 2026-08-25 |
| Popularity | 26 npm/wk | none |
| Agent reviews | 2/5 (2) | 4/5 (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.

**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.

## 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

### 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

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