One MCP server. Every API your agent needs.

Drop the Callio MCP server into Cursor, Claude, Antigravity, or any MCP-compatible client and your agent can call 143 APIs through one Callio key.

How MCP works with Callio

Model Context Protocol (MCP) is how tools like Cursor and Antigravity connect to external capabilities. The editor starts a small MCP server; the AI can call tools that server exposes (instead of you wiring one integration per API).

End-to-end flow

  1. You add the Callio MCP server to your config and set CALLIO_API_KEY.
  2. Cursor / Antigravity launches that server as a subprocess (stdio). It appears under Settings → MCP with three tools.
  3. When you chat, the model can invoke search_apis and get_api_info — they read Callio's public catalog (same data as Browse).
  4. To actually execute an API through Callio's gateway, the model uses call_api. That sends a request to https://callio.dev/api/proxy/… with your key — same as the HTTP proxy in our docs.
  5. For upstream APIs that need your own provider key (OpenAI, SendGrid, etc.), save it once on the API's page on Callio; the proxy attaches it when call_api runs.

Why only three tools?

One tool per vendor would mean hundreds of MCP tools. Callio exposes discover → describe → call so the agent can use any listed API without new MCP releases per provider.

After you edit config

Restart the MCP server (Cursor: Command Palette → MCP restart, or restart the app) so new env vars and keys load. Confirm the server shows a green status and lists all three tools.

Works with your favorite AI tools

Claude Code

Anthropic's coding agent

~/.claude/claude_desktop_config.json

Cursor

AI-powered code editor

.cursor/mcp.json

Antigravity

AI development platform

MCP Settings

Setup in 2 minutes

Get your Callio API key

Sign up at callio.dev and generate an API key from your dashboard.

Add to your AI tool config

Copy this JSON into your MCP configuration file. Replace the API key with your own.

{
  "mcpServers": {
    "callio": {
      "command": "npx",
      "args": ["-y", "github:hmadhsan/callio-mcp"],
      "env": {
        "CALLIO_API_KEY": "callio_your_key_here"
      }
    }
  }
}

Claude Code: ~/.claude/claude_desktop_config.json

Cursor: .cursor/mcp.json

Antigravity: MCP Settings panel

Start using APIs

Your agent now has 3 powerful tools. Just ask in natural language:

"Search for email APIs on Callio"

"What endpoints does the SendGrid API have?"

"Get post #1 from JSONPlaceholder through Callio"

"Search for AI companies using Apollo API"

3 tools, unlimited power

search_apis

Discover and browse 143 APIs by name, category, or description.

get_api_info

Get full details — endpoints, parameters, examples, auth info.

call_api

Execute any API call. Auth, rate limits, and routing all handled.

Ready to supercharge your agent?

Get started in under 2 minutes. Free accounts include 5 proxy requests/month; paid plans add more.