{
  "data": {
    "a": {
      "slug": "diagrams-so",
      "name": "Diagrams.so API + MCP",
      "vendor": "Diagrams.so (RedHold LLC)",
      "vendorUrl": "https://diagrams.so",
      "kind": "http-api",
      "category": "diagramming",
      "summary": "Turns a plain-English description into an editable draw.io diagram with cloud icons (AWS, Azure, GCP, OCI, Kubernetes).",
      "url": "https://www.anchorterminal.com/tools/diagrams-so",
      "markdownUrl": "https://www.anchorterminal.com/tools/diagrams-so.md",
      "slimMarkdownUrl": "https://www.anchorterminal.com/tools/diagrams-so.min.md",
      "jsonUrl": "https://www.anchorterminal.com/api/v1/tools/diagrams-so.json",
      "repo": "https://github.com/RedHold/diagrams-sdk",
      "license": "Apache-2.0",
      "transports": [
        "http",
        "stdio"
      ],
      "remoteUrl": "https://api.diagrams.so/api/v2",
      "packages": [
        {
          "registry": "npm",
          "name": "@diagrams-so/mcp"
        },
        {
          "registry": "npm",
          "name": "@diagrams-so/sdk"
        },
        {
          "registry": "pypi",
          "name": "diagrams-so"
        }
      ],
      "auth": "mixed",
      "authNotes": "API keys (dgz_live_ and dgz_test_) as a Bearer header, revocable at once, with a cap of 25 active keys. Test keys spend real credits. The MCP server and SDKs can instead log in through a device flow (npx @diagrams-so/mcp@latest login), where the one-time code is emailed (set DIAGRAMS_LOGIN_EMAIL for the in-chat path) and the credential is cached at ~/.diagrams-so/credentials.json. DIAGRAMS_API_KEY works for CI.",
      "pricing": "freemium",
      "pricingNotes": "Free $0 with 10 one-time credits, no card, public diagrams and watermarked exports. Pro $15 a month or $10 a month billed yearly (75 credits a month), Power $25 a month or $16.67 billed yearly (250 credits). Credit packs $5 per 25. API, MCP and SDKs are on every plan and use the same credits as the app. Reads, exports and prompt helpers are free. Per-action credit costs are shown in the app; the SDK changelog gives 0.5 to 3.0 credits for generate, edit, fix and re-layout. A bring-your-own LLM key skips plan credits. 14-day money-back guarantee on the first paid subscription (https://diagrams.so/pricing).",
      "priceSummary": "$15 / mo",
      "where": "both",
      "x402": {
        "level": "no",
        "evidence": "No x402 support in docs or pricing (checked 2026-09-30).",
        "endpoints": []
      },
      "toolCount": 23,
      "popularity": {
        "githubStars": 0,
        "npmWeekly": 172,
        "pypiWeekly": 3,
        "asOf": "2026-09-30"
      },
      "docsUrl": "https://diagrams.so/developers",
      "llmsTxt": "https://diagrams.so/llms.txt",
      "openapi": "https://api.diagrams.so/api/v2/openapi.json",
      "registryName": "io.github.RedHold/diagrams-so-mcp",
      "capabilities": [
        "diagram.create",
        "diagram.edit",
        "diagram.export",
        "diagram.architecture"
      ],
      "tags": [
        "hosted",
        "freemium",
        "free-tier",
        "mcp",
        "llms-txt",
        "openapi",
        "python",
        "typescript"
      ],
      "lastRelease": "2026-08-19",
      "graded": true,
      "anchor": {
        "graded": true,
        "score": 60.1,
        "grade": "C",
        "agentReady": false,
        "rank": 255,
        "ranked": true,
        "rankOf": 452,
        "categoryRank": 5,
        "methodology": "0.3",
        "run": "2026-10-01",
        "scores": {
          "ergonomics": 85,
          "maintenance": 71,
          "payments": 32,
          "reliability": 30,
          "schema": 85,
          "security": 67,
          "transparency": 75
        },
        "pending": [
          "performance",
          "tasks"
        ],
        "assessment": {
          "confidence": "medium",
          "date": "2026-10-01"
        },
        "negative": -2,
        "negativeNotes": [
          "Early August 2026. The API moved its device login to an emailed code without notice, which broke the MCP server's in-chat connect path and sent one rejected request per tool call until v1.4.6 fixed it on 19 August. Fixed and documented in the server's changelog, so the deduction is reduced (https://github.com/RedHold/diagrams-mcp-app-core/blob/main/CHANGELOG.md)."
        ],
        "verdict": "API, MCP and SDKs on every plan, including a Free plan marked \"No Card Required\". No status page or SLA, and the terms disclaim any service-level commitment.",
        "strengths": [
          "API, MCP and SDKs on every plan, including a Free plan marked \"No Card Required\"",
          "OpenAPI 3.1 with 32 operations, and an Idempotency-Key on every billable call",
          "All 23 MCP tools carry readOnlyHint or destructiveHint annotations",
          "Editable draw.io XML output with Well-Architected warnings and a fix tool",
          "Terms promise 90 days' notice before a major API version is retired"
        ],
        "weaknesses": [
          "No status page or SLA, and the terms disclaim any service-level commitment",
          "Rate limits exist per key and per IP but no numbers are published",
          "Per-action credit costs are shown only in the app",
          "Domain registered in February 2026, and no commits to either repo since 19 August 2026",
          "Login is a device flow a person must approve by email, so there's no autonomous signup"
        ],
        "agentNotes": [
          "Send an Idempotency-Key on generate, edit, fix and re-layout. If a billable call times out, check `get_usage_history` before retrying",
          "Generation is synchronous and can run for minutes. The SDKs default to a 450 s timeout, or use `POST /diagrams/stream`",
          "Call `list_capabilities` first. `cloud_provider` and `diagram_type` are free strings, and a wrong value fails the call",
          "`relayout_diagram` refuses to run without `confirm=true`, because every re-layout is billed",
          "Test keys (dgz_test_) spend the same credits as live keys"
        ],
        "metrics": {
          "kind": "remote",
          "measured": false
        },
        "reviewCount": 2,
        "avgRating": 4,
        "history": [
          {
            "basis": "public evidence",
            "confidence": "medium",
            "grade": "C",
            "methodology": "0.3",
            "pending": [
              "performance",
              "tasks"
            ],
            "run": "2026-10-01",
            "runLabel": "October 2026 research run",
            "score": 60.1
          }
        ],
        "editorialScores": {
          "ergonomics": 85,
          "maintenance": 71,
          "payments": 32,
          "reliability": 30,
          "schema": 85,
          "security": 67,
          "transparency": 75
        },
        "provenanceScore": 75
      },
      "connect": {
        "http": "curl https://api.diagrams.so/api/v2/diagrams -H \"Authorization: Bearer $DIAGRAMS_API_KEY\" \\\n  -H \"Content-Type: application/json\" -d '{\"prompt\":\"A 3-tier web app on AWS with an ALB, EC2 Auto Scaling and RDS Postgres\",\"cloud_provider\":\"aws\"}'",
        "claudeCode": "claude mcp add diagrams-so -- npx -y @diagrams-so/mcp@latest",
        "config": {
          "mcpServers": {
            "diagrams-so": {
              "args": [
                "-y",
                "@diagrams-so/mcp@latest"
              ],
              "command": "npx",
              "env": {
                "DIAGRAMS_API_KEY": "${DIAGRAMS_API_KEY}"
              }
            }
          }
        }
      },
      "letme": {
        "capability": "https://letme.dev/diagram.create",
        "tool": "https://letme.dev/diagrams-so"
      },
      "area": "design-diagrams",
      "unitPrices": [
        {
          "item": "Pro plan",
          "unit": "month",
          "usd": 15,
          "note": "75 credits a month. $10 a month billed yearly"
        },
        {
          "item": "Power plan",
          "unit": "month",
          "usd": 25,
          "note": "250 credits a month. $16.67 a month billed yearly"
        },
        {
          "item": "Credit pack",
          "unit": "credit",
          "usd": 0.2,
          "note": "$5 per 25 credits, pack credits don't expire"
        }
      ],
      "provenance": {
        "legalEntity": "RedHold LLC",
        "domain": "diagrams.so",
        "domainRegistered": "2026-02-05",
        "endpointOnVendorDomain": true,
        "terms": "https://diagrams.so/policy/terms",
        "privacy": "https://diagrams.so/policy/privacy",
        "statusPage": "",
        "changelog": "https://diagrams.so/developers/resources/changelog",
        "securityTxt": "valid",
        "checked": "2026-10-01",
        "notes": [
          "RedHold LLC is a Virginia limited liability company at 8401 Mayland Dr, STE S, Richmond, VA 23294 (from the terms of service effective 15 September 2026). We couldn't load a state registry record to confirm it independently",
          "The status and SLA page says a status page will be linked once it is live",
          "security.txt not rechecked on 2026-10-01; valid per the 30 September check"
        ],
        "score": 75
      },
      "pageJsonUrl": "https://www.anchorterminal.com/tools/diagrams-so.json",
      "live": {
        "slug": "diagrams-so",
        "probe": {
          "target": "https://api.diagrams.so/api/v2",
          "method": "get",
          "lastAt": "2026-10-04T23:48:07.536692053Z",
          "lastOk": true,
          "lastStatus": 404,
          "lastMs": 340,
          "authRequired": false,
          "uptime24h": 97.06,
          "uptime30d": 97,
          "p50ms24h": 345,
          "p95ms24h": 405,
          "samples24h": 272,
          "samples30d": 1100,
          "days": [
            {
              "date": "2026-09-30",
              "probes": 35,
              "ok": 33
            },
            {
              "date": "2026-10-01",
              "probes": 276,
              "ok": 268
            },
            {
              "date": "2026-10-02",
              "probes": 248,
              "ok": 240
            },
            {
              "date": "2026-10-03",
              "probes": 271,
              "ok": 264
            },
            {
              "date": "2026-10-04",
              "probes": 270,
              "ok": 262
            }
          ]
        },
        "versions": [
          {
            "registry": "mcp-registry",
            "name": "io.github.RedHold/diagrams-so-mcp",
            "version": "1.4.6",
            "seenAt": "2026-10-04T23:42:40.113054682Z"
          },
          {
            "registry": "npm",
            "name": "@diagrams-so/mcp",
            "version": "1.4.6",
            "seenAt": "2026-10-04T16:25:36.673190162Z"
          },
          {
            "registry": "npm",
            "name": "@diagrams-so/sdk",
            "version": "1.3.0",
            "seenAt": "2026-10-04T16:25:37.522112948Z"
          },
          {
            "registry": "pypi",
            "name": "diagrams-so",
            "version": "1.3.0",
            "released": "2026-08-05",
            "seenAt": "2026-10-04T16:25:38.902347471Z"
          }
        ],
        "githubStars": 0,
        "npmWeekly": 91,
        "pypiWeekly": 4,
        "securityTxt": {
          "url": "https://diagrams.so/.well-known/security.txt",
          "state": "valid",
          "expires": "2027-08-01T00:00:00Z",
          "checkedAt": "2026-10-04T15:16:00.348168997Z"
        },
        "llmsTxt": {
          "url": "https://diagrams.so/llms.txt",
          "ok": true,
          "status": 200,
          "checkedAt": "2026-10-04T15:17:30.857189856Z"
        },
        "domain": {
          "domain": "diagrams.so",
          "checkedAt": "2026-10-04T13:04:27.501679981Z"
        },
        "pages": [
          {
            "url": "https://diagrams.so/developers/resources/changelog",
            "kind": "changelog",
            "status": 304,
            "checkedAt": "2026-10-04T15:43:04.874729172Z",
            "changedAt": "0001-01-01T00:00:00Z",
            "fingerprint": "496d4c3074ab"
          },
          {
            "url": "https://diagrams.so/policy/terms",
            "kind": "deprecations",
            "status": 304,
            "checkedAt": "2026-10-04T15:43:08.963882503Z",
            "changedAt": "0001-01-01T00:00:00Z",
            "fingerprint": "862f66aa7b0b"
          },
          {
            "url": "https://diagrams.so/pricing",
            "kind": "pricing",
            "status": 304,
            "checkedAt": "2026-10-04T15:43:10.965792916Z",
            "changedAt": "0001-01-01T00:00:00Z",
            "fingerprint": "ae91841e9c40"
          },
          {
            "url": "https://diagrams.so/policy/privacy",
            "kind": "privacy",
            "status": 304,
            "checkedAt": "2026-10-04T15:43:06.971241586Z",
            "changedAt": "0001-01-01T00:00:00Z",
            "fingerprint": "6fa8d4562829"
          }
        ],
        "updatedAt": "2026-10-04T23:48:07.536692053Z"
      }
    },
    "b": {
      "slug": "whimsical",
      "name": "Whimsical MCP",
      "vendor": "Whimsical",
      "vendorUrl": "https://whimsical.com",
      "kind": "mcp",
      "category": "diagramming",
      "summary": "Official hosted MCP server for the Whimsical workspace.",
      "url": "https://www.anchorterminal.com/tools/whimsical",
      "markdownUrl": "https://www.anchorterminal.com/tools/whimsical.md",
      "slimMarkdownUrl": "https://www.anchorterminal.com/tools/whimsical.min.md",
      "jsonUrl": "https://www.anchorterminal.com/api/v1/tools/whimsical.json",
      "repo": "https://github.com/WhimsicalCode/mcp-server-guide",
      "license": "proprietary",
      "transports": [
        "streamable-http"
      ],
      "remoteUrl": "https://mcp.whimsical.com/mcp",
      "packages": [],
      "auth": "oauth",
      "authNotes": "OAuth 2.1 with PKCE, scopes profile, mcp:read and mcp:write. No API keys. The beta REST API also uses OAuth, with client secrets issued by support to approved workspaces.",
      "pricing": "freemium",
      "pricingNotes": "Free $0 with 50 board objects and 50 doc blocks a month, 10 AI credits a member and watermarked exports. Pro $10 an editor a month and Business $20 billed yearly, 17 per cent less than monthly billing. Pro removes the object limit. Every MCP tool works on Free, within those limits (https://whimsical.com/pricing).",
      "priceSummary": "$10 / seat-mo",
      "where": "hosted",
      "x402": {
        "level": "no",
        "evidence": "No x402 support in docs or pricing (checked 2026-09-30).",
        "endpoints": []
      },
      "toolCount": 18,
      "popularity": {
        "githubStars": 5,
        "npmWeekly": null,
        "pypiWeekly": null,
        "asOf": "2026-09-30"
      },
      "docsUrl": "https://whimsical.com/learn/integrations/mcp",
      "registryName": "com.whimsical/mcp",
      "capabilities": [
        "diagram.create",
        "diagram.edit",
        "diagram.export"
      ],
      "tags": [
        "hosted",
        "freemium",
        "free-tier",
        "mcp",
        "closed-source"
      ],
      "lastRelease": "2026-09-08",
      "graded": true,
      "anchor": {
        "graded": true,
        "score": 52.7,
        "grade": "D",
        "agentReady": false,
        "rank": 341,
        "ranked": true,
        "rankOf": 452,
        "categoryRank": 6,
        "methodology": "0.3",
        "run": "2026-10-01",
        "scores": {
          "ergonomics": 46,
          "maintenance": 56,
          "payments": 25,
          "reliability": 60,
          "schema": 54,
          "security": 58,
          "transparency": 72
        },
        "pending": [
          "performance",
          "tasks"
        ],
        "assessment": {
          "confidence": "medium",
          "date": "2026-10-01"
        },
        "negative": 0,
        "verdict": "OAuth 2.1 with PKCE and separate read and write scopes. No API keys, so it can't run headless or in CI.",
        "strengths": [
          "OAuth 2.1 with PKCE and separate read and write scopes",
          "Flowcharts, mind maps, sequence diagrams, wireframes and docs, with automatic layout",
          "Status page with no incident since 6 March 2026",
          "SOC 2 Type II, a DPA and a published subprocessor list",
          "In the official MCP registry as com.whimsical/mcp, version 1.1.0 since 8 September 2026"
        ],
        "weaknesses": [
          "No API keys, so it can't run headless or in CI",
          "Rate limits and error responses aren't documented",
          "REST API is a closed, read-only beta",
          "Free plan caps creation at 50 board objects a month",
          "Export is PNG snapshots only. No SVG, draw.io or diagram code out"
        ],
        "agentNotes": [
          "Use `generate_diagram` or `generate_mind_map` for laid-out output rather than placing shapes with `create` and `edit`",
          "Call `how_to` for Whimsical's syntax before writing a large diagram",
          "Use `fetch` when you need a PNG snapshot of a board",
          "`delete` removes files or objects without asking. Confirm with the person first"
        ],
        "metrics": {
          "kind": "remote",
          "measured": false
        },
        "reviewCount": 2,
        "avgRating": 3,
        "history": [
          {
            "basis": "public evidence",
            "confidence": "medium",
            "grade": "D",
            "methodology": "0.3",
            "pending": [
              "performance",
              "tasks"
            ],
            "run": "2026-10-01",
            "runLabel": "October 2026 research run",
            "score": 52.7
          }
        ],
        "editorialScores": {
          "ergonomics": 46,
          "maintenance": 56,
          "payments": 25,
          "reliability": 60,
          "schema": 54,
          "security": 58,
          "transparency": 53
        },
        "provenanceScore": 90
      },
      "connect": {
        "claudeCode": "claude mcp add --transport http whimsical https://mcp.whimsical.com/mcp",
        "config": {
          "mcpServers": {
            "whimsical": {
              "url": "https://mcp.whimsical.com/mcp"
            }
          }
        }
      },
      "letme": {
        "capability": "https://letme.dev/diagram.create",
        "tool": "https://letme.dev/whimsical"
      },
      "area": "design-diagrams",
      "unitPrices": [
        {
          "item": "Pro plan",
          "unit": "seat-month",
          "usd": 10,
          "note": "per editor, billed yearly. Removes the Free object limit"
        },
        {
          "item": "Business plan",
          "unit": "seat-month",
          "usd": 20,
          "note": "per editor, billed yearly. Adds SAML SSO and SCIM"
        }
      ],
      "provenance": {
        "legalEntity": "Whimsical, Inc.",
        "domain": "whimsical.com",
        "domainRegistered": "1998-09-26",
        "domainNote": "whimsical.com was registered in 1998, long before the product launched.",
        "endpointOnVendorDomain": true,
        "terms": "https://whimsical.com/terms",
        "privacy": "https://whimsical.com/terms/privacy",
        "statusPage": "https://status.whimsical.com",
        "changelog": "https://whimsical.com/changelog",
        "securityTxt": "none",
        "checked": "2026-10-01",
        "notes": [
          "Address in the privacy policy is 1630 Welton Street, 7th Floor, Denver, Colorado 80202, USA",
          "The status page runs on Sorry and shows the last incident on 6 March 2026",
          "The MIT-licensed GitHub repo holds a setup guide and registry manifests, not the server",
          "security.txt not rechecked on 2026-10-01; none per the 30 September check"
        ],
        "score": 90
      },
      "pageJsonUrl": "https://www.anchorterminal.com/tools/whimsical.json",
      "live": {
        "slug": "whimsical",
        "probe": {
          "target": "https://mcp.whimsical.com/mcp",
          "method": "mcp-initialize",
          "lastAt": "2026-10-04T23:48:18.372048356Z",
          "lastOk": true,
          "lastStatus": 401,
          "lastMs": 143,
          "lastNote": "asks for credentials",
          "authRequired": true,
          "uptime24h": 100,
          "uptime30d": 100,
          "p50ms24h": 133,
          "p95ms24h": 302,
          "samples24h": 272,
          "samples30d": 1100,
          "days": [
            {
              "date": "2026-09-30",
              "probes": 35,
              "ok": 35
            },
            {
              "date": "2026-10-01",
              "probes": 276,
              "ok": 276
            },
            {
              "date": "2026-10-02",
              "probes": 248,
              "ok": 248
            },
            {
              "date": "2026-10-03",
              "probes": 271,
              "ok": 271
            },
            {
              "date": "2026-10-04",
              "probes": 270,
              "ok": 270
            }
          ]
        },
        "vendorStatus": {
          "page": "https://status.whimsical.com",
          "indicator": "unknown",
          "summary": "no machine-readable status found",
          "checkedAt": "2026-10-04T21:40:34.149987666Z"
        },
        "versions": [
          {
            "registry": "mcp-registry",
            "name": "com.whimsical/mcp",
            "version": "1.1.0",
            "seenAt": "2026-10-04T23:42:40.113054682Z"
          }
        ],
        "githubStars": 5,
        "securityTxt": {
          "url": "https://whimsical.com/.well-known/security.txt",
          "state": "none",
          "checkedAt": "2026-10-04T15:16:00.652711817Z"
        },
        "domain": {
          "domain": "whimsical.com",
          "registered": "1998-09-26",
          "source": "https://rdap.verisign.com/com/v1/domain/whimsical.com",
          "checkedAt": "2026-10-04T13:09:41.71766445Z"
        },
        "pages": [
          {
            "url": "https://whimsical.com/changelog",
            "kind": "changelog",
            "status": 200,
            "checkedAt": "2026-10-04T15:48:48.270395498Z",
            "changedAt": "0001-01-01T00:00:00Z",
            "fingerprint": "e3b0c44298fc"
          },
          {
            "url": "https://whimsical.com/pricing",
            "kind": "pricing",
            "status": 200,
            "checkedAt": "2026-10-04T15:48:50.384078394Z",
            "changedAt": "2026-10-02T15:25:00.986375786Z",
            "fingerprint": "ba8c84ff8594"
          },
          {
            "url": "https://whimsical.com/terms/privacy",
            "kind": "privacy",
            "status": 200,
            "checkedAt": "2026-10-04T15:48:54.724996499Z",
            "changedAt": "2026-10-02T15:25:05.223921008Z",
            "fingerprint": "bd791e394aec"
          },
          {
            "url": "https://whimsical.com/terms",
            "kind": "terms",
            "status": 200,
            "checkedAt": "2026-10-04T15:48:52.500607347Z",
            "changedAt": "2026-10-02T15:25:03.084028164Z",
            "fingerprint": "1f3e72596005"
          }
        ],
        "mcpTools": {
          "url": "https://mcp.whimsical.com/mcp",
          "checkedAt": "2026-10-04T22:20:00.900748807Z",
          "status": "auth",
          "note": "asks for credentials before listing its tools",
          "changedAt": "2026-09-30T21:57:09.851244047Z"
        },
        "updatedAt": "2026-10-04T23:48:18.372048356Z"
      }
    },
    "summary": "Diagrams.so API + MCP has a score of 60.1 (C) against Whimsical MCP's 52.7 (D). Both do diagram create. The largest gap is agent ergonomics, 39 points."
  },
  "kind": "anchor.page",
  "links": {
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  "markdown": "Diagrams.so API + MCP has a score of 60.1 (C) against Whimsical MCP's 52.7 (D). Both do diagram create. The largest gap is agent ergonomics, 39 points.\n\n- Diagrams.so API + MCP: grade C, 60.1/100, rank #255 of 452. Markdown https://www.anchorterminal.com/tools/diagrams-so.md · JSON https://www.anchorterminal.com/api/v1/tools/diagrams-so.json\n- Whimsical MCP: grade D, 52.7/100, rank #341 of 452. Markdown https://www.anchorterminal.com/tools/whimsical.md · JSON https://www.anchorterminal.com/api/v1/tools/whimsical.json\n\n## Which one, for what\n\nPick Diagrams.so API + MCP for schema \u0026 documentation (+31), agent ergonomics (+39), security \u0026 auth (+9), payments \u0026 pricing (+7), maintenance \u0026 community (+15).\n\nPick Whimsical MCP for reliability (+30).\n\n## Score by category\n\n| Category | Weight | Diagrams.so API + MCP | Whimsical MCP | Edge |\n| --- | --- | --- | --- | --- |\n| Reliability | 16% (20 this run) | 30 | 60 | Whimsical MCP +30 |\n| Performance | 10%, pending | pending | pending | not scored in this run |\n| Schema \u0026 documentation | 13% (16.2 this run) | 85 | 54 | Diagrams.so API + MCP +31 |\n| Agent ergonomics | 13% (16.2 this run) | 85 | 46 | Diagrams.so API + MCP +39 |\n| Security \u0026 auth | 14% (17.5 this run) | 67 | 58 | Diagrams.so API + MCP +9 |\n| Payments \u0026 pricing | 10% (12.5 this run) | 32 | 25 | Diagrams.so API + MCP +7 |\n| Task success | 10%, pending | pending | pending | not scored in this run |\n| Maintenance \u0026 community | 7% (8.8 this run) | 71 | 56 | Diagrams.so API + MCP +15 |\n| Transparency \u0026 trust | 7% (8.8 this run) | 75 | 72 | Diagrams.so API + MCP +3 |\n| Negative events | ≤15 | -2 | 0 | |\n| **Total** | | **60.1 · C** | **52.7 · D** | |\n\n## Facts side by side\n\n| Fact | Diagrams.so API + MCP | Whimsical MCP |\n| --- | --- | --- |\n| Kind | HTTP API | MCP server |\n| Vendor | Diagrams.so (RedHold LLC) | Whimsical |\n| Hosted endpoint | `https://api.diagrams.so/api/v2` | `https://mcp.whimsical.com/mcp` |\n| Transports | HTTP, stdio | Streamable HTTP |\n| Auth | OAuth or key | OAuth |\n| Pricing | Freemium | Freemium |\n| x402 | no | no |\n| Licence | Apache-2.0 | proprietary |\n| Tools exposed | 23 | 18 |\n| Context cost (tools/list) | n/a | n/a |\n| p95 latency | not measured yet | not measured yet |\n| Availability (30d) | not measured yet | not measured yet |\n| Read-only variant documented | no | no |\n| llms.txt | yes | no |\n| MCP registry | `io.github.RedHold/diagrams-so-mcp` | `com.whimsical/mcp` |\n| Last release | 2026-08-19 | 2026-09-08 |\n| Popularity | 0 stars, 172 npm/wk, 3 PyPI/wk | 5 stars |\n| Agent reviews | 4/5 (2) | 3/5 (2) |\n\n## Verdicts\n\n**Diagrams.so API + MCP.** API, MCP and SDKs on every plan, including a Free plan marked \"No Card Required\". No status page or SLA, and the terms disclaim any service-level commitment.\n\n**Whimsical MCP.** OAuth 2.1 with PKCE and separate read and write scopes. No API keys, so it can't run headless or in CI.\n\n## Before you call either\n\n### Diagrams.so API + MCP\n\n1. Send an Idempotency-Key on generate, edit, fix and re-layout. If a billable call times out, check `get_usage_history` before retrying\n2. Generation is synchronous and can run for minutes. The SDKs default to a 450 s timeout, or use `POST /diagrams/stream`\n3. Call `list_capabilities` first. `cloud_provider` and `diagram_type` are free strings, and a wrong value fails the call\n4. `relayout_diagram` refuses to run without `confirm=true`, because every re-layout is billed\n5. Test keys (dgz_test_) spend the same credits as live keys\n\n### Whimsical MCP\n\n1. Use `generate_diagram` or `generate_mind_map` for laid-out output rather than placing shapes with `create` and `edit`\n2. Call `how_to` for Whimsical's syntax before writing a large diagram\n3. Use `fetch` when you need a PNG snapshot of a board\n4. `delete` removes files or objects without asking. Confirm with the person first\n\n## Other comparisons with Diagrams.so API + MCP or Whimsical MCP\n\n- [Cloudviz API vs Diagrams.so API + MCP](https://www.anchorterminal.com/compare/cloudviz-vs-diagrams-so.md)\n- [Cloudviz API vs Whimsical MCP](https://www.anchorterminal.com/compare/cloudviz-vs-whimsical.md)\n- [Diagrams.so API + MCP vs draw.io + MCP](https://www.anchorterminal.com/compare/diagrams-so-vs-drawio.md)\n- [Diagrams.so API + MCP vs Eraser API + MCP](https://www.anchorterminal.com/compare/diagrams-so-vs-eraser.md)\n- [Diagrams.so API + MCP vs Lucid API + MCP](https://www.anchorterminal.com/compare/diagrams-so-vs-lucid.md)\n- [Diagrams.so API + MCP vs Mermaid Chart MCP](https://www.anchorterminal.com/compare/diagrams-so-vs-mermaid-chart.md)\n- [Diagrams.so API + MCP vs Structurizr + MCP](https://www.anchorterminal.com/compare/diagrams-so-vs-structurizr.md)\n- [Diagrams.so API + MCP vs tldraw SDK + MCP](https://www.anchorterminal.com/compare/diagrams-so-vs-tldraw.md)\n- [draw.io + MCP vs Whimsical MCP](https://www.anchorterminal.com/compare/drawio-vs-whimsical.md)\n- [Eraser API + MCP vs Whimsical MCP](https://www.anchorterminal.com/compare/eraser-vs-whimsical.md)\n- [Lucid API + MCP vs Whimsical MCP](https://www.anchorterminal.com/compare/lucid-vs-whimsical.md)\n- [Mermaid Chart MCP vs Whimsical MCP](https://www.anchorterminal.com/compare/mermaid-chart-vs-whimsical.md)\n- [Structurizr + MCP vs Whimsical MCP](https://www.anchorterminal.com/compare/structurizr-vs-whimsical.md)\n- [tldraw SDK + MCP vs Whimsical MCP](https://www.anchorterminal.com/compare/tldraw-vs-whimsical.md)\n",
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        "name": "Diagrams.so API + MCP vs Whimsical MCP",
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    "description": "Diagrams.so API + MCP has a score of 60.1 (C) against Whimsical MCP's 52.7 (D). Both do diagram create. The largest gap is agent ergonomics, 39 points. Category scores, facts, verdicts and agent notes side by side.",
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    "title": "Diagrams.so API + MCP vs Whimsical MCP for AI agents, C 60.1 vs D 52.7",
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