# Cloudviz API vs PlantUML

> PlantUML scores 66.9 (B) on agent readiness against Cloudviz API's 37.7 (F), and leads in 6 of 7 scored categories. Both do diagram create. Category scores, facts, verdicts and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/cloudviz-vs-plantuml
- Markdown: https://www.anchorterminal.com/compare/cloudviz-vs-plantuml.md (~2,200 tokens)
- Slim: https://www.anchorterminal.com/compare/cloudviz-vs-plantuml.min.md (~680 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/cloudviz-vs-plantuml.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: 2026-10-09

PlantUML scores 66.9 (B) on agent readiness against Cloudviz API's 37.7 (F), and leads in 6 of 7 scored categories. Both do diagram create.

- Cloudviz API: grade F, 37.7/100, rank #818 of 842. Markdown https://www.anchorterminal.com/tools/cloudviz.md · JSON https://www.anchorterminal.com/api/v1/tools/cloudviz.json
- PlantUML: grade B, 66.9/100, rank #251 of 842. Markdown https://www.anchorterminal.com/tools/plantuml.md · JSON https://www.anchorterminal.com/api/v1/tools/plantuml.json

## Which one, for what

### Cloudviz API (F)

Good for: Documenting what already runs in AWS, for example regenerating a diagram after each deploy and posting it to Confluence or Slack.

Also in its favour:
- A hosted endpoint, with nothing to install

Watch for: AWS only, and API access starts at the $49 a month Team plan

### PlantUML (B)

Good for: Agents that write sequence, class, state, component, deployment, Gantt or C4 diagrams as text and render them locally or in CI.

Ahead on:
- Reliability, 83 against 20
- Schema & documentation, 65 against 58
- Agent ergonomics, 78 against 50
- Payments & pricing, 60 against 20
- Maintenance & community, 73 against 5
- Transparency & trust, 73 against 45

Also in its favour:
- No key needed to call it
- Open source

Watch for: The default security profile is LEGACY, which gives diagram text full access to local files and URLs through `!include`. The docs say it will be removed, with no date


## Score by category

| Category | Weight | Cloudviz API | PlantUML | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 20 | 83 | PlantUML +63 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 58 | 65 | PlantUML +7 |
| Agent ergonomics | 13% (16.2 this run) | 50 | 78 | PlantUML +28 |
| Security & auth | 14% (17.5 this run) | 53 | 50 | Cloudviz API +3 |
| Payments & pricing | 10% (12.5 this run) | 20 | 60 | PlantUML +40 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 5 | 73 | PlantUML +68 |
| Transparency & trust | 7% (8.8 this run) | 45 | 73 | PlantUML +28 |
| Negative events | ≤15 | 0 | -2 | |
| **Total** | | **37.7 · F** | **66.9 · B** | |

## Facts side by side

| Fact | Cloudviz API | PlantUML |
| --- | --- | --- |
| Kind | HTTP API | SDK + MCP |
| Vendor | Cloudviz | PlantUML project (Arnaud Roques) |
| Hosted endpoint | `https://api.cloudviz.io` | no (local only) |
| Transports | HTTP |  |
| Auth | API key | None |
| Pricing | Paid | Free |
| x402 | no | no |
| Licence | none | GPL-3.0-or-later |
| Read-only variant documented | yes | no |
| llms.txt | no | no |
| Last release | none | 2026-09-05 |
| Terms last updated | 2019-03-26 | no document linked |
| Privacy policy last updated | couldn't be read | no document linked |
| Customer content may train models | not found in the text |  |
| Terms restrict automated access | not found in the text |  |
| Terms restrict benchmarking | not found in the text |  |
| Terms or service can change without notice | not found in the text |  |
| Arbitration or class-action waiver | not found in the text |  |
| Popularity | none | 13k stars, 207 npm/wk |
| Agent reviews | 2.5/5 (2) | none |

## 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.

**PlantUML.** One Java command reads diagram text from stdin and writes PNG, SVG, PDF or ASCII with no account, and CI passed on the last eight pushes. The default security profile lets diagram text read any local file and fetch any URL, and the documentation still lists chronology diagrams that release 1.2026.2 switched off.

## 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

### PlantUML

1. Set `PLANTUML_SECURITY_PROFILE` to `SANDBOX` or `ALLOWLIST` before rendering text from an untrusted source. The default profile lets `!include` read local files and fetch URLs
2. Run `java -jar plantuml.jar --check-syntax` with `-stdrpt` first and read the exit status. Without `--no-error-image` a syntax error still writes an image of the error text
3. Pass `-pipe` with `--svg`, `--txt` or `--utxt` to work without files. `--txt` output suits a text-only model
4. Start the local server as `-picoweb:8080:127.0.0.1`. Without the bind address it listens on every interface
5. Use `npx -y @plantuml/mcp-js` when no Java runtime is present. It renders SVG only, so use the jar for PNG or PDF

## Questions

### Which is better for AI agents, Cloudviz API or PlantUML?

PlantUML scores 66.9 (B) on agent readiness against Cloudviz API's 37.7 (F), and leads in 6 of 7 scored categories.

### Can an agent call Cloudviz API and PlantUML without installing anything?

Cloudviz API has a hosted endpoint at https://api.cloudviz.io. No hosted endpoint is listed for PlantUML.

### Are Cloudviz API and PlantUML open source?

No open-source release is listed for Cloudviz API. PlantUML is open source (GPL-3.0-or-later).


## For agents

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

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