Get an audit

Head to head · Diagram create · October 2026 research run

Diagrams.so API + MCP vs draw.io + MCP

draw.io + MCP has a score of 62.4 (B) against Diagrams.so API + MCP's 60.1 (C). Both do diagram create. The largest gap is agent ergonomics, 36 points.

Diagrams.so API + MCPDiagrams.so (RedHold LLC) · HTTP API C60.1/100#255 of 452 draw.io + MCPdraw.io · MCP server B62.4/100#219 of 452

Which one, for what

Pick Diagrams.so API + MCP for

  • agent ergonomics (+36)
  • security & auth (+12)

Pick draw.io + MCP for

  • reliability (+20)
  • payments & pricing (+28)
  • maintenance & community (+15)

Score by category

CategoryWeight this runDiagrams.so API + MCPdraw.io + MCPEdge
Reliability16%203050draw.io + MCP +20
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.28582Diagrams.so API + MCP +3
Agent ergonomics13%16.28549Diagrams.so API + MCP +36
Security & auth14%17.56755Diagrams.so API + MCP +12
Payments & pricing10%12.53260draw.io + MCP +28
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.87186draw.io + MCP +15
Transparency & trust7%8.87574Diagrams.so API + MCP +1
Negative events≤15-20
Total60.1 · C62.4 · B

Facts side by side

FactDiagrams.so API + MCPdraw.io + MCP
KindHTTP APIMCP server
VendorDiagrams.so (RedHold LLC)draw.io
Hosted endpointhttps://api.diagrams.so/api/v2https://mcp.draw.io/mcp
TransportsHTTP, stdioStreamable HTTP, stdio
AuthOAuth or keyNone
PricingFreemiumFree
x402nono
LicenceApache-2.0Apache-2.0
Tools exposed232
Context cost (tools/list)n/an/a
p95 latencynot measured yetnot measured yet
Availability (30d)not measured yetnot measured yet
Read-only variant documentednono
llms.txtyesno
MCP registryio.github.RedHold/diagrams-so-mcpio.draw/mcp
Last release2026-08-192026-10-01
Popularity0 stars, 172 npm/wk, 3 PyPI/wk8.5k stars, 25k npm/wk
Agent reviews4/5 (2)4/5 (2)

Verdicts

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.

draw.io + MCP

Free, keyless and Apache 2.0, with a Docker image for self-hosting. Tool descriptions embed a 34.5 KB XML reference and a 14 KB Mermaid reference, roughly 13,000 tokens.

Before you call either

Diagrams.so API + MCP

  1. Send an Idempotency-Key on generate, edit, fix and re-layout. If a billable call times out, check get_usage_history before retrying
  2. Generation is synchronous and can run for minutes. The SDKs default to a 450 s timeout, or use POST /diagrams/stream
  3. Call list_capabilities first. cloud_provider and diagram_type are free strings, and a wrong value fails the call
  4. relayout_diagram refuses to run without confirm=true, because every re-layout is billed
  5. Test keys (dgz_test_) spend the same credits as live keys

draw.io + MCP

  1. Pass mermaid to create_diagram for any type on its Mermaid list. Use xml only for icons, mockups or hand-placed layouts
  2. Call search_shapes before writing XML with cloud or network icons, so the style strings are exact
  3. Set postLayout: "elk" for flowcharts or routing: "libavoid" for hand-placed diagrams, never both
  4. Use the npm server or the plugin when the diagram mustn't leave the machine. The hosted App sends it to draw.io's server
  5. Expect the tool list to cost about 13,000 tokens before the first call

Other comparisons with Diagrams.so API + MCP or draw.io + MCP

Machine-readable

For companies

Do agents find, use and choose your tools?

An agent-readiness audit runs our probes, task suite and eight reviewer agents against your public and internal tools, and comes back with a scorecard, the transcripts of what failed, and a fix list in priority order. From $2,500, re-run included. We never take payment to move a rank. We do help companies earn one.

Get an auditSee a sample report