Use ApexDiagram's network tools from Claude, ChatGPT or Cursor
A free MCP server at apexdiagram.com/mcp gives any AI assistant subnet calculators, file importers, a design wizard and a network linter; diagrams it builds can be saved to your account.
ApexDiagram runs a public Model Context Protocol server at https://apexdiagram.com/mcp. It needs no account and no API key. Add it to your AI assistant and it can calculate subnets, turn an nmap scan or pfSense config into a diagram, design a network for a site from a head count, check a design against ApexDiagram's rules, and hand you a link to the finished diagram.
What the tools do
| Tool | What you can ask |
|---|---|
subnet_calculator, ip_facts | "What is the broadcast address of 10.1.2.0/23?", "Is 100.72.1.9 a private address?" |
generate_ip_list | "List every host in 192.168.10.0/24 except the gateway and the DHCP pool, as CSV" |
vlsm_plan | "Split 10.20.0.0/16 into subnets for 500 users, 60 phones, 20 servers and 8 printers" |
summarize_routes | "Summarise these twelve prefixes into the fewest routes" |
design_network | "Design a network for a 40-person office with guest Wi-Fi and cameras" |
import_network_file | "Turn this nmap XML / pfSense config / draw.io file / UniFi export into a diagram" |
create_draft_diagram | "Draw the network I just described" |
lint_diagram | "Check this design for mistakes" |
firewall_rules | "Give me the iptables rules for these flows" |
bill_of_materials | "What equipment does this design need?" |
containerlab_topology | "Make a containerlab file I can run this lab from" |
Any diagram the assistant builds is kept as a draft for seven days and comes with a link. Open it to see the diagram drawn in every view, then sign in or create a free account to save it to your workspace, where you can keep editing it, run the full assistant, share it and export it.
Add it to your assistant
Claude (claude.ai and the desktop app). Settings → Connectors → Add custom connector, name it ApexDiagram, URL https://apexdiagram.com/mcp, no authentication. Turn it on in a chat from the tools menu.
Claude Code.
claude mcp add --transport http apexdiagram https://apexdiagram.com/mcp
ChatGPT. Settings → Connectors → Advanced → turn on Developer mode, then Create: name ApexDiagram, URL https://apexdiagram.com/mcp, authentication None. Enable the connector in a chat. Custom connectors need a paid ChatGPT plan.
Cursor. Settings → MCP → Add new MCP server, or put this in .cursor/mcp.json:
{ "mcpServers": { "apexdiagram": { "url": "https://apexdiagram.com/mcp" } } }
VS Code (Copilot agent mode). In .vscode/mcp.json:
{ "servers": { "apexdiagram": { "type": "http", "url": "https://apexdiagram.com/mcp" } } }
Gemini CLI, Windsurf, Zed, Codex and others. Add an HTTP (Streamable HTTP) MCP server with the same URL. A client that only speaks stdio can bridge with npx -y mcp-remote https://apexdiagram.com/mcp.
Limits and privacy
- Calls are limited per address (120 a minute) and drafts to 30 a day. Heavier or automated use belongs on an API key with the authenticated server, which also reads and edits your own diagrams.
- Files you import are parsed in memory and not stored; only the resulting diagram is kept, as the draft, until it is claimed or expires.
- The server never calls a language model itself. The reasoning happens in your assistant, on your plan; the tools only compute and draw.
- Drafts are not listed anywhere: whoever has the link can view them, like a share link, so treat the link accordingly.
Your own diagrams
To let an assistant read and change diagrams that already live in your organisation, create an API key and connect to /api/mcp instead; that server has the full set of editing tools and a sync_diagram call that keeps a diagram in step with code. See Create an API key.
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