Diagrams and software architecture APIs and MCP servers for AI agents
Render or edit diagrams (Mermaid, PlantUML, C4), whiteboards and architecture models.
9 diagrams and software architecture APIs an AI agent can call: auth method and header, official MCP server (6), free tier (7), docs links. Machine-readable JSON included. Agents: fetch catalog/diagrams-software-architecture.json instead of parsing this page. Last checked 2026-09-24.
Ratings and usage (★) fetched: .
| Service | What an agent can do | Auth | MCP server | Free tier | Details (with sources) | Notes | Proof (ratings, usage) |
|---|---|---|---|---|---|---|---|
| Eraser API (DiagramGPT) | Generate diagrams from text prompts (DiagramGPT) and manage Eraser files programmatically via REST API. | API keyAuthorization: Bearer <api_token> | official | paid only - API tokens require an active paid team plan | Base URL: https://app.eraser.io/api Free plan: none ↗ | No free tier for API access - tokens are only issued to paid teams, not free accounts. The official remote MCP server (OAuth or API key; local npm @eraserlabs/eraser-mcp) is free within in-app free-tier limits. | — |
| IcePanel API | Programmatically create, read, import, and export C4-style architecture landscapes and models via REST API. | API keyX-API-Key: <ICEPANEL_API_KEY>; OpenAPI 3.1 spec published at api.icepanel.io | official | free tier: 10,000 read requests/mo, 1,000 write requests/mo, 5 import/export requests/mo | Base URL: https://api.icepanel.io/v1 Free plan: 10,000 read, 1,000 write, 5 import and 5 export API requests, per month, no card ↗ Rate limits: GET/HEAD 2,400/min; POST/PUT/PATCH/DELETE 60/min; POST /user/* 10/min; 429 with Retry-After ↗ Example call: list model objects in a landscape: GET https://api.icepanel.io/v1/landscapes/{landscapeId}/versions/latest/model/objects ↗ | Free plan has monthly request caps; higher volume requires Growth ($40/editor/mo), Scale ($80/editor/mo) or Enterprise. Official remote MCP (OAuth) is documented as paid plans only; the local IcePanel/mcp-server repo is deprecated. | SourceForge 5.0★/1 review |
| Kroki | Render 25+ diagram-as-code formats (PlantUML, Mermaid, C4, GraphViz, BPMN, etc.) from text via a free HTTP GET/POST API. | none | — | free, no key; public hosted instance at kroki.io sponsored by Exoscale (no SLA) | Base URL: https://kroki.io Free plan: no_key, no card ↗ Example call: render a diagram from text source: POST https://kroki.io/{diagram_type}/{output_format} ↗ | No authentication or signup required; text diagram in, image out; can be self-hosted via Docker for privacy or higher volume. | — |
| Lucid (Lucidchart) REST API | Create, read, search, and manage Lucidchart documents and folders programmatically via REST API. | API key / OAuthAuthorization: Bearer <api_key> or OAuth 2.0 access token | official | check pricing | Base URL: https://api.lucid.co OAuth scopes: lucidchart.document.content, lucidchart.document.content:readonly, folder, user.profile ↗ | Requires enabling Developer Tools on the account first; supports both API-key and OAuth 2.0 client-credential flows; exact free-tier API quota not published in docs. The official MCP server (OAuth, since 2025-11-18) must be enabled by an account admin. | — |
| Mermaid Chart API | Validate, render, and save Mermaid diagrams via Mermaid Chart's official MCP server using an account API token. | API keyAPI token from account settings; MCP tools use bearer-style auth | official | unauthenticated MCP validate/render tools are free; saving to a Mermaid Chart account needs a token, check pricing for limits | Free plan: no_key, no card ↗ MCP tools: 11: validate_and_render_mermaid_diagram, get_diagram_title, get_diagram_summary, search_mermaid_icons, get_mermaid_syntax_document, list_tools … ↗ | Broad REST API docs are gated behind a Google Form request (contact-to-access); the MCP server (HTTP https://mcp.mermaid.ai/mcp, SSE https://mcp.mermaid.ai/sse) is the practical self-serve agent interface today. | — |
| Miro REST API | Create/read boards and items via REST API, or use Miro's official MCP server to search, build, and summarize boards. | OAuth 2.0Authorization: Bearer <access_token> (OAuth 2.0 authorization code flow, or OAuth 2.1 for MCP) | official | Free tier: up to 3 editable team boards; MCP on all plans, capped per day at 100 tool calls on Free (Starter 500, Business 2,000, Enterprise 10,000) | Base URL: https://api.miro.com/v2 Free plan: 100 MCP tool calls, per day ↗ Rate limits: Credit-based per user per app: global 100,000 credits/min; Level 1 call = 50 credits (2,000 req/min), Level 2 = 100 credits (1,000 req/min) ↗ OAuth scopes: boards:read, boards:write, identity:read ↗ Example call: create a sticky note on a board: POST https://api.miro.com/v2/boards/{board_id}/sticky_notes ↗ MCP tools: 20: board_create, board_search_boards, canvas_get_canvas_composer_skill, canvas_load_format_skill, canvas_search, canvas_create_from_svg … ↗ | REST access tokens expire in 1 hour (refresh token 60 days); MCP server supports OIDC for enterprise data-safety controls. | — |
| Napkin AI API | Generate diagrams, flowcharts, mind maps, and charts from text via REST API, exporting to SVG, PNG, or PPT. | API keyAuthorization: Bearer <api_token> | — | included on every plan; any account can create a token and call the API, limited by credits | Base URL: https://api.napkin.ai/v1 Free plan: 500 AI credits per week (shared with the app), watermarked ↗ Rate limits: POST /v1/visual throttled per second/minute/hour/day by plan; X-RateLimit-* and Retry-After headers ↗ Async jobs: POST /v1/visual returns request id; poll GET /v1/visual/{id}/status; file URLs expire after 30 min ↗ Example call: create a visual from text: POST https://api.napkin.ai/v1/visual ↗ | Credit-based usage; requests fail with a no_credits error once a team's credits are exhausted. | — |
| PlantUML Server API | Render UML and architecture-as-code diagrams to PNG/SVG/ASCII via a free public HTTP GET API using encoded diagram text. | none | — | free, no key; public hosted server at plantuml.com/plantuml | Base URL: https://www.plantuml.com/plantuml Free plan: no_key, no card ↗ Example call: render a diagram to PNG: GET https://www.plantuml.com/plantuml/png/{ENCODED_SOURCE} ↗ MCP tools: 1: plantuml_version ↗ | Extremely widely used for UML/C4/architecture-as-code; no signup; self-hostable via plantuml.war for privacy or rate-limit control. The official plantuml/plantuml-mcp is an MVP exposing only plantuml_version (no rendering yet). | — |
| Structurizr | Create and update C4-model software architecture diagram workspaces as JSON via a signed HTTPS API. | API keyX-Authorization header: apiKey:base64(HMAC-SHA256(apiSecret, digest)) plus Nonce header | official | free tier: workspaces up to 0.5MB; paid plans raise the limit to 5MB | Base URL: https://api.structurizr.com Rate limits: Rate limiting enforced on all workspace API calls (GET and PUT); no number published ↗ MCP tools: 6: inspect, parse, validate, export-mermaid, export-c4plantuml, export-plantuml ↗ | Cloud service is end-of-life (migrate to playground, local or self-hosted server per docs.structurizr.com/cloud). Uses a nonstandard HMAC signing scheme rather than a bearer token; docs recommend the Structurizr CLI or client libraries over the raw API. | — |
Other categories
- Web search
- Web scraping and browser automation
- Knowledge and research data
- Image generation and editing
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- Speech and audio
- Music generation
- 3D generation and assets
- Architecture, CAD and BIM
- Design and UI
- Documents, OCR and presentations
- Translation and language
- Code execution sandboxes
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- Cloud and hosting
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- Vector search, memory and RAG
- Email, team chat and notifications
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- Voice agents and telephony
- Productivity and workspace
- CRM, support and marketing
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- Maps, geolocation and weather
- Finance, payments and market data
- E-commerce
- Automation and integration platforms
- Model APIs and inference