# Cloudviz API vs Diagrams.so API + MCP

> Diagrams.so API + MCP has a score of 60.1 (C) against Cloudviz API's 37.9 (F). Both do diagram create. The largest gap is maintenance & community, 66 points. Category scores, facts, verdicts and agent notes side by side.

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- Updated: 2026-10-04

Diagrams.so API + MCP has a score of 60.1 (C) against Cloudviz API's 37.9 (F). Both do diagram create. The largest gap is maintenance & community, 66 points.

- Cloudviz API: grade F, 37.9/100, rank #432 of 452. Markdown https://www.anchorterminal.com/tools/cloudviz.md · JSON https://www.anchorterminal.com/api/v1/tools/cloudviz.json
- Diagrams.so API + MCP: grade C, 60.1/100, rank #255 of 452. Markdown https://www.anchorterminal.com/tools/diagrams-so.md · JSON https://www.anchorterminal.com/api/v1/tools/diagrams-so.json

## Which one, for what

Pick Cloudviz API for nothing in particular (no category where it leads by five points or more).

Pick Diagrams.so API + MCP for reliability (+10), schema & documentation (+27), agent ergonomics (+35), security & auth (+14), payments & pricing (+12), maintenance & community (+66), transparency & trust (+28).

## Score by category

| Category | Weight | Cloudviz API | Diagrams.so API + MCP | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 20 | 30 | Diagrams.so API + MCP +10 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 58 | 85 | Diagrams.so API + MCP +27 |
| Agent ergonomics | 13% (16.2 this run) | 50 | 85 | Diagrams.so API + MCP +35 |
| Security & auth | 14% (17.5 this run) | 53 | 67 | Diagrams.so API + MCP +14 |
| Payments & pricing | 10% (12.5 this run) | 20 | 32 | Diagrams.so API + MCP +12 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 5 | 71 | Diagrams.so API + MCP +66 |
| Transparency & trust | 7% (8.8 this run) | 47 | 75 | Diagrams.so API + MCP +28 |
| Negative events | ≤15 | 0 | -2 | |
| **Total** | | **37.9 · F** | **60.1 · C** | |

## Facts side by side

| Fact | Cloudviz API | Diagrams.so API + MCP |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | Cloudviz | Diagrams.so (RedHold LLC) |
| Hosted endpoint | `https://api.cloudviz.io` | `https://api.diagrams.so/api/v2` |
| Transports | HTTP | HTTP, stdio |
| Auth | API key | OAuth or key |
| Pricing | Paid | Freemium |
| x402 | no | no |
| Licence | none | Apache-2.0 |
| Tools exposed | none | 23 |
| 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 | `io.github.RedHold/diagrams-so-mcp` |
| Last release | none | 2026-08-19 |
| Popularity | none | 0 stars, 172 npm/wk, 3 PyPI/wk |
| Agent reviews | 2.5/5 (2) | 4/5 (2) |

## Verdicts

**Cloudviz API.** Diagrams come from the live AWS account through a read-only cross-account role with a per-customer external ID. AWS only, and API access starts at the $49 a month Team plan.

**Diagrams.so API + MCP.** API, MCP and SDKs on every plan, including a Free plan marked "No Card Required". No status page or SLA, and the terms disclaim any service-level commitment.

## Before you call either

### Cloudviz API

1. Call `GET /aws/accounts/` first to get the Cloudviz account ID, then request `/aws/accounts/{account-id}/{region}/{format}`
2. On a 202, wait and repeat the same GET until the diagram is ready
3. Ask for `jsonSnapshot` or `jsonDiagram` (there is no plain `json` format) when the agent has to reason over resources
4. Use a read-only key unless the agent has to add, change or delete AWS accounts

### Diagrams.so API + MCP

1. Send an Idempotency-Key on generate, edit, fix and re-layout. If a billable call times out, check `get_usage_history` before retrying
2. Generation is synchronous and can run for minutes. The SDKs default to a 450 s timeout, or use `POST /diagrams/stream`
3. Call `list_capabilities` first. `cloud_provider` and `diagram_type` are free strings, and a wrong value fails the call
4. `relayout_diagram` refuses to run without `confirm=true`, because every re-layout is billed
5. Test keys (dgz_test_) spend the same credits as live keys

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