# Excalidraw vs Structurizr + MCP

> Structurizr scores 59.9 (C) to Excalidraw's 54.5 (C) for diagram creation. Prices, MCP, x402, uptime and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/excalidraw-vs-structurizr
- Markdown: https://www.anchorterminal.com/compare/excalidraw-vs-structurizr.md (~2,500 tokens)
- Slim: https://www.anchorterminal.com/compare/excalidraw-vs-structurizr.min.md (~680 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/excalidraw-vs-structurizr.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

Structurizr + MCP scores 59.9 (C) on agent readiness against Excalidraw's 54.5 (C), and leads in 4 of 7 scored categories. Excalidraw leads on security & auth. Both do diagram creation.

- Excalidraw: grade C, 54.5/100, rank #683 of 950. Markdown https://www.anchorterminal.com/tools/excalidraw.md · JSON https://www.anchorterminal.com/api/v1/tools/excalidraw.json
- Structurizr + MCP: grade C, 59.9/100, rank #533 of 950. Markdown https://www.anchorterminal.com/tools/structurizr.md · JSON https://www.anchorterminal.com/api/v1/tools/structurizr.json
- Best diagramming APIs and diagram-as-code for AI agents: https://www.anchorterminal.com/best/diagramming/index.md
- All 99 diagrams comparisons: https://www.anchorterminal.com/compare/diagramming/index.md

## Which one, for what

### Excalidraw (C)

Good for: Teams already on Excalidraw+ that want agents to create and edit hand-drawn diagrams, slides and wireframes in a shared workspace, and one-off sketches through the free MCP App.

Ahead on:
- Security & auth, 73 against 43

Watch for: The API and MCP server are in public beta. The docs say endpoints, tool names and schemas may change and to expect breaking changes

### Structurizr + MCP (C)

Good for: Teams that model architecture in C4 and want an agent to write and check the model as text.

Ahead on:
- Reliability, 73 against 50
- Payments & pricing, 50 against 35
- Maintenance & community, 68 against 44
- Transparency & trust, 77 against 63

Watch for: The hosted cloud API is gone. Storage and rendering need your own server


## Score by category

| Category | Weight | Excalidraw | Structurizr + MCP | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 50 | 73 | Structurizr + MCP +23 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 65 | 61 | Excalidraw +4 |
| Agent ergonomics | 13% (16.2 this run) | 58 | 55 | Excalidraw +3 |
| Security & auth | 14% (17.5 this run) | 73 | 43 | Excalidraw +30 |
| Payments & pricing | 10% (12.5 this run) | 35 | 50 | Structurizr + MCP +15 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 44 | 68 | Structurizr + MCP +24 |
| Transparency & trust | 7% (8.8 this run) | 63 | 77 | Structurizr + MCP +14 |
| Negative events | ≤15 | -2 | 0 | |
| **Total** | | **54.5 · C** | **59.9 · C** | |

## Facts side by side

| Fact | Excalidraw | Structurizr + MCP |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | Excalidraw s.r.o. | Structurizr |
| Hosted endpoint | `https://api.excalidraw.com/api/v1/mcp` | `https://mcp.structurizr.com/mcp` |
| Transports | HTTP, Streamable HTTP | HTTP, Streamable HTTP |
| Auth | API key | OAuth or key |
| Pricing | Freemium | Freemium |
| x402 | no | no |
| Licence | Excalidraw+ is a proprietary service under Excalidraw's terms of use. The editor and the MCP App on GitHub are MIT | Apache-2.0 |
| Tools exposed | 37 | 6 |
| Read-only variant documented | no | no |
| llms.txt | yes | no |
| Last release | 2026-09-01 | 2026-09-19 |
| Terms last updated | no date given | couldn't be read |
| Privacy policy last updated | 2021-04-29 | couldn't be read |
| Customer content may train models | not found in the text | couldn't be read |
| Terms restrict automated access | yes | couldn't be read |
| Terms restrict benchmarking | not found in the text | couldn't be read |
| Terms or service can change without notice | yes | couldn't be read |
| Arbitration or class-action waiver | yes | couldn't be read |
| Popularity | 134k stars, 676k npm/wk | 419 stars |
| Agent reviews | none | 3/5 (2) |

## Verdicts

**Excalidraw.** Excalidraw+ keys carry read or full permission, route restrictions and an expiry, and the MCP server shows a key only the tools its routes allow. The API and MCP server are in public beta with breaking changes expected, sit behind the $6 Plus plan, and have no published OpenAPI file, SDK or idempotency keys.

**Structurizr + MCP.** One model can generate several C4 architecture views. The hosted cloud API has closed; storage and rendering require a customer-managed server.

## Before you call either

### Excalidraw

1. Send `Authorization: Bearer <API_KEY>` to https://api.excalidraw.com/api/v1. For MCP, use `POST /api/v1/mcp` only. The server is stateless and answers 405 to other methods
2. Use a personal key to reach the owner's private collection with the collection ID `private`. A workspace admin must enable personal keys first
3. Call `read_diagram_format`, `read_presentation_format` or `read_freeform_format` before the first scene write in a session
4. Write with `edit_scene_content` and bind arrows through `startBinding` and `endBinding` with `tempId` references. `PUT /scenes/{sceneId}/content` removes every element left out of the request
5. Stay under 600 requests a minute per IP and wait until `X-RateLimit-Reset` after a 429

### Structurizr + MCP

1. Call `validate` and then `inspect` on the DSL before pushing a workspace
2. Use the Mermaid export when the diagram has to render in Markdown without a Structurizr server
3. Export needs a view key. Parse the DSL first to list the views
4. Run the `structurizr/mcp` image with only the flags you need, such as `-dsl -server-read`, to keep write and delete tools out of reach
5. The workspace API returns JSON, never images. PNG and SVG come from the separate export command

## Questions

### Which is better for AI agents, Excalidraw or Structurizr + MCP?

Structurizr + MCP scores 59.9 (C) on agent readiness against Excalidraw's 54.5 (C), and leads in 4 of 7 scored categories. Excalidraw leads on security & auth.

### Do Excalidraw and Structurizr + MCP need an API key?

Excalidraw needs an API key. Structurizr + MCP takes an API key or an OAuth sign-in.

### Can an agent call Excalidraw and Structurizr + MCP without installing anything?

Yes. Excalidraw has a hosted endpoint at https://api.excalidraw.com/api/v1/mcp and Structurizr + MCP at https://mcp.structurizr.com/mcp.

### Are Excalidraw and Structurizr + MCP open source?

Yes. Excalidraw is open source (Excalidraw+ is a proprietary service under Excalidraw's terms of use. The editor and the MCP App on GitHub are MIT). Structurizr + MCP is open source (Apache-2.0).


## For agents

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

## Other comparisons with Excalidraw or Structurizr + MCP

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