QuickstartAPI key auth

Base URL

https://api.openephemeris.com

Auth — API Key

Use X-OpenEphemeris-API-Key in your app or server. Generate a key from the dashboard to start testing.

Auth — MCP / AI Tools

No key needed. Run npx -y @openephemeris/mcp-server — auto-connects via OAuth Device Auth. Credentials are cached and auto-refresh.

Auth — Remote MCP (Claude Web, ChatGPT)

No local install. Add https://mcp.openephemeris.com/mcp as a custom connector — leave OAuth Client ID and Secret blank. The server uses OAuth 2.1 + PKCE with Dynamic Client Registration; your client handles auth via a browser popup on first connect.

First request

curl -X POST "https://api.openephemeris.com/ephemeris/natal-chart" \
  -H "X-OpenEphemeris-API-Key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "subject": {
      "name": "Jane Smith",
      "birth_datetime": { "iso": "1985-03-20T08:15:00" },
      "birth_location": {
        "latitude": { "decimal": 37.7749 },
        "longitude": { "decimal": -122.4194 },
        "timezone": { "iana_name": "America/Los_Angeles" }
      }
    }
  }'

Every endpoint shows its credit cost up front — design with clarity before you write a line of integration code.