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Two plans, both unlimited
  • Two plans. Free at 0,andPaidat0, and Paid at 20 a month or $120 a year. Both get unlimited diagrams and edits in the web app, the API, the MCP server and the SDKs. The only limit is the per-minute rate limit.
  • Free gets no draw.io file. Replies that carried the XML now carry xml: null, xml_withheld: true, xml_withheld_reason: "UPGRADE_REQUIRED", an export_url for a watermarked SVG and an upgrade_url. export?format=drawio returns 403 UPGRADE_REQUIRED. Paid replies are unchanged. See Free plan replies.
  • Removed: credit packs, monthly allowances, rollover, soft caps, referral rewards, and bring your own key (BYO). credits_remaining is always -1, and 402 QUOTA_EXCEEDED is no longer returned. The fields stay so old code keeps working.
  • diagram_type: "auto" picks the type from the prompt. Leaving diagram_type out still means architecture.
  • New diagrams start private on every plan. Make one public with PATCH /diagrams/{id}.
  • MCP server 1.4.7. The generate_diagram tool no longer tells your AI client that the type defaults to architecture, so the client can leave it out or send "auto". Tool text no longer mentions credits.
  • SDKs 1.4.0 (Python diagrams-so, TypeScript @diagrams-so/sdk). diagram_type is optional: when you don’t pass it, the SDK leaves it out of the request. Pass "auto" to let Diagrams.so pick. The docs no longer mention credits.
  • Docs: billing/credits-and-pricing is now billing/plans-and-pricing. The old link redirects.
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Connect without an API key
  • Device login. Run npx @diagrams-so/mcp@latest login (or diagrams_so.login() in Python): enter your email, we email you a one-time code, then sign in and enter it in the browser. The client is connected, with no key copied or pasted. The code is emailed, never placed in a URL, and only the account that owns that email can approve, so a link can’t be used from anyone else’s browser. Every sign-in method works, including Google and magic link.
  • MCP server 1.4.2. Adds login, logout, whoami, and install. An unconnected machine gets a connect link on the first tool call, so Claude Desktop users never need a terminal.
  • SDKs 1.3.0 (Python diagrams-so, TypeScript @diagrams-so/sdk). login(), a shared credential store, a DIAGRAMS_LOGIN_EMAIL env var for non-interactive use, and an upgrade link on 402 errors.
  • Exports are free on every plan. Free-plan exports carry a small watermark.
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Developer platform
  • Public /api/v2 API: generate, edit, fix, re-layout, import, export, versions, gallery, prompt helpers, usage, and meta.
  • MCP server (@diagrams-so/mcp): create and iterate diagrams from Claude, Cursor, and VS Code, with per-task usage attribution.
  • SDKs: Python (diagrams-so) and TypeScript (@diagrams-so/sdk).
  • API keys with scopes, test mode, reveal-once creation, and instant revocation.
This page tracks developer-facing changes. Non-breaking additions ship continuously; breaking changes ship only under a new API version. See Versioning.