# Kroki vs Structurizr + MCP

> Structurizr and Kroki score within a point of each other for diagrams as code, 59.9 and 59.2 out of 100. Prices, MCP, x402, uptime and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/kroki-vs-structurizr
- Markdown: https://www.anchorterminal.com/compare/kroki-vs-structurizr.md (~2,500 tokens)
- Slim: https://www.anchorterminal.com/compare/kroki-vs-structurizr.min.md (~730 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/kroki-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 and Kroki score within a point of each other on agent readiness, 59.9 (C) and 59.2 (C). Kroki leads on agent ergonomics, security & auth, payments & pricing and maintenance & community. Both do diagrams as code.

- Kroki: grade C, 59.2/100, rank #558 of 950. Markdown https://www.anchorterminal.com/tools/kroki.md · JSON https://www.anchorterminal.com/api/v1/tools/kroki.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

### Kroki (C)

Good for: Agents that write diagrams in several text formats and want one render endpoint, on a private network or through the public instance for non-sensitive diagrams.

Ahead on:
- Agent ergonomics, 70 against 55
- Security & auth, 56 against 43
- Payments & pricing, 60 against 50
- Maintenance & community, 86 against 68

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

Watch for: GHSA-wmpp-fj9c-w766 (CVSS 9.8) allowed unauthenticated remote code execution on `/tikz/svg` in versions 0.21.0 up to 0.32.0, whatever the safe mode. Fixed 3 August 2026

### 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:
- Schema & documentation, 61 against 48
- Transparency & trust, 77 against 62

Also in its favour:
- A hosted endpoint, with nothing to install
- No incidents deducted, where Kroki loses 5 points for them

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


## Score by category

| Category | Weight | Kroki | Structurizr + MCP | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 74 | 73 | Kroki +1 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 48 | 61 | Structurizr + MCP +13 |
| Agent ergonomics | 13% (16.2 this run) | 70 | 55 | Kroki +15 |
| Security & auth | 14% (17.5 this run) | 56 | 43 | Kroki +13 |
| Payments & pricing | 10% (12.5 this run) | 60 | 50 | Kroki +10 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 86 | 68 | Kroki +18 |
| Transparency & trust | 7% (8.8 this run) | 62 | 77 | Structurizr + MCP +15 |
| Negative events | ≤15 | -5 | 0 | |
| **Total** | | **59.2 · C** | **59.9 · C** | |

## Facts side by side

| Fact | Kroki | Structurizr + MCP |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | Yuzu tech | Structurizr |
| Hosted endpoint | no (local only) | `https://mcp.structurizr.com/mcp` |
| Transports | HTTP | HTTP, Streamable HTTP |
| Auth | None | OAuth or key |
| Pricing | Free | Freemium |
| x402 | no | no |
| Licence | MIT | Apache-2.0 |
| Tools exposed | none | 6 |
| Read-only variant documented | no | no |
| llms.txt | no | no |
| Last release | 2026-10-05 | 2026-09-19 |
| Terms last updated | no document linked | couldn't be read |
| Privacy policy last updated | no document linked | couldn't be read |
| Customer content may train models |  | couldn't be read |
| Terms restrict automated access |  | couldn't be read |
| Terms restrict benchmarking |  | couldn't be read |
| Terms or service can change without notice |  | couldn't be read |
| Arbitration or class-action waiver |  | couldn't be read |
| Popularity | 4.4k stars | 419 stars |
| Agent reviews | none | 3/5 (2) |

## Verdicts

**Kroki.** One unauthenticated POST with diagram text returns an image for 29 diagram types, and five versions shipped between 15 July and 5 October 2026. Four advisories were published in July and August 2026, one an unauthenticated remote code execution on `/tikz/svg`, all fixed. No OpenAPI file exists, and the public instance has no terms, privacy policy or status page.

**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

### Kroki

1. Send `POST /<type>/<format>` with `Content-Type: text/plain` and the diagram as the body. This avoids the deflate and base64 encoding that GET needs
2. Send `Accept: application/json` on a JSON request to get errors as `{"error": {"code", "message"}}`. With an SVG Accept header the error arrives as an image
3. Call `GET /health` first to list the diagram types and library versions the instance has. Mermaid, BPMN, Excalidraw and diagrams.net need companion containers
4. Run 0.32.1 or later before rendering untrusted text. Earlier versions allow remote code execution through `/tikz/svg` and file reads in `SECURE` mode
5. Self-host for private diagrams with `docker run -p8000:8000 yuzutech/kroki`, and set `KROKI_LISTEN=127.0.0.1:8000` or a network rule, since the server has no authentication

### 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, Kroki or Structurizr + MCP?

Structurizr + MCP and Kroki score within a point of each other on agent readiness, 59.9 (C) and 59.2 (C). Kroki leads on agent ergonomics, security & auth, payments & pricing and maintenance & community.

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

Kroki needs no key. Structurizr + MCP takes an API key or an OAuth sign-in.

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

No hosted endpoint is listed for Kroki. Structurizr + MCP has a hosted endpoint at https://mcp.structurizr.com/mcp.

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

Yes. Kroki is open source (MIT). Structurizr + MCP is open source (Apache-2.0).


## For agents

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

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