# Cloudviz API vs D2

> D2 scores 65.3 (B) on agent readiness against Cloudviz API's 37.7 (F), and leads in 6 of 7 scored categories. Cloudviz API leads on security & auth. Both do diagram create. Category scores, facts, verdicts and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/cloudviz-vs-d2
- Markdown: https://www.anchorterminal.com/compare/cloudviz-vs-d2.md (~2,100 tokens)
- Slim: https://www.anchorterminal.com/compare/cloudviz-vs-d2.min.md (~680 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/cloudviz-vs-d2.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

D2 scores 65.3 (B) on agent readiness against Cloudviz API's 37.7 (F), and leads in 6 of 7 scored categories. Cloudviz API leads on security & auth. 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
- D2: grade B, 65.3/100, rank #295 of 842. Markdown https://www.anchorterminal.com/tools/d2.md · JSON https://www.anchorterminal.com/api/v1/tools/d2.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.

Ahead on:
- Security & auth, 53 against 48

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

### D2 (B)

Good for: Agents that need to produce or edit architecture, sequence, grid, SQL table or class diagrams as reviewable text and render them locally.

Ahead on:
- Reliability, 68 against 20
- Schema & documentation, 65 against 58
- Agent ergonomics, 78 against 50
- Payments & pricing, 60 against 20
- Maintenance & community, 74 against 5
- Transparency & trust, 69 against 45

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

Watch for: No 1.0 release. The maintainer lists a stable 1.0 with a formal grammar as a goal, and 0.8.2 changed Dagre and ELK layout output


## Score by category

| Category | Weight | Cloudviz API | D2 | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 20 | 68 | D2 +48 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 58 | 65 | D2 +7 |
| Agent ergonomics | 13% (16.2 this run) | 50 | 78 | D2 +28 |
| Security & auth | 14% (17.5 this run) | 53 | 48 | Cloudviz API +5 |
| Payments & pricing | 10% (12.5 this run) | 20 | 60 | D2 +40 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 5 | 74 | D2 +69 |
| Transparency & trust | 7% (8.8 this run) | 45 | 69 | D2 +24 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **37.7 · F** | **65.3 · B** | |

## Facts side by side

| Fact | Cloudviz API | D2 |
| --- | --- | --- |
| Kind | HTTP API | SDK + MCP |
| Vendor | Cloudviz | D2 project (The Hack Foundation) |
| Hosted endpoint | `https://api.cloudviz.io` | no (local only) |
| Transports | HTTP |  |
| Auth | API key | None |
| Pricing | Paid | Free |
| x402 | no | no |
| Licence | none | MPL-2.0 |
| Read-only variant documented | yes | no |
| llms.txt | no | no |
| Last release | none | 2026-09-07 |
| 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 | 26k stars, 22k 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.

**D2.** A single local command turns text into a diagram in six formats with no account, key or network call, and CI passes on the default branch. The language is at 0.9.0 with no stable release, its company sponsor has shut down, and one maintainer with limited time wrote every commit since July.

## 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

### D2

1. Check the exit status of `d2`, never the output file. The man page says a partial render can be written when an error occurs
2. Run `d2 validate file.d2` before rendering, and `d2 fmt` to normalise the source
3. Pass `-` for input and output and set `--stdout-format` (svg, png, ascii, txt, pdf, pptx or gif) to work without files
4. Use `--stdout-format ascii` when the reader is a text-only model
5. Pass `--bundle=false` or review image URLs and imports before rendering D2 text from an untrusted source. Release 0.9.0 fetches remote images when bundling

## Questions

### Which is better for AI agents, Cloudviz API or D2?

D2 scores 65.3 (B) on agent readiness against Cloudviz API's 37.7 (F), and leads in 6 of 7 scored categories. Cloudviz API leads on security & auth.

### Can an agent call Cloudviz API and D2 without installing anything?

Cloudviz API has a hosted endpoint at https://api.cloudviz.io. No hosted endpoint is listed for D2.

### Are Cloudviz API and D2 open source?

No open-source release is listed for Cloudviz API. D2 is open source (MPL-2.0).


## For agents

- This comparison as JSON: https://www.anchorterminal.com/compare/cloudviz-vs-d2.json, and with the fewest tokens: https://www.anchorterminal.com/compare/cloudviz-vs-d2.min.md
- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {"a": "cloudviz", "b": "d2"}`. From a terminal: `anchor compare cloudviz d2`
- Each listing in full: https://www.anchorterminal.com/api/v1/tools/cloudviz.json and https://www.anchorterminal.com/api/v1/tools/d2.json

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- [D2 vs Whimsical MCP](https://www.anchorterminal.com/compare/d2-vs-whimsical.md)
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