The MCP connector stack

R21 runs agents against production systems, not sample data.

The shape of it, confirmed 2026-08-20: automation and anything needing an external trigger runs on n8n, on R21's own server. Hosting is Vercel. Domains sit at Cloudflare.

Make.com is deliberately absent. It was retired in the 2026-08-16 cutover to n8n, and listing a tool R21 no longer runs would be the exact failure this site exists to prevent.

The remaining entries are MCP servers observed connected in a live working session. The homepage renders this list's length rather than a typed number, so when the stack changes the count changes with it.