European electricity data, inside your AI assistant

Ask ChatGPT or Claude about tomorrow's power prices in any of 43 European bidding zones and get real numbers — day-ahead prices at native 15-minute resolution, forecasts whose accuracy is published daily, carbon intensity, and cheapest-window optimization. One hosted server, two minutes of setup, free tier without a card.

Everything below authenticates with one API key from voltcast.com/register (free, no card). The MCP endpoint is:

https://voltcast.com/api/mcp

Claude (claude.ai, Desktop & mobile)

Custom connectors work on every Claude plan (Free allows one). Claude connects from Anthropic's cloud, so nothing runs on your machine.

1 — claude.ai → Settings → Connectors → Add custom connector
2 — URL: https://voltcast.com/api/mcp
3 — Under Request headers, add authorization with value Bearer YOUR_API_KEY → Add
4 — In a chat, enable Voltcast via the + menu, then ask: "What's tomorrow's electricity price forecast for DE-LU?"

Claude Desktop (local alternative): add {"mcpServers":{"voltcast":{"command":"npx","args":["voltcast-mcp"],"env":{"VOLTCAST_API_KEY":"YOUR_API_KEY"}}}} to claude_desktop_config.json.

ChatGPT

Two routes, depending on your plan:

MCP connector Plus/Pro with Developer Mode, Business, Enterprise

1 — Settings → Apps & Connectors (enable Developer Mode under Settings → Security if you don't see "Create")
2 — Create → server URL https://voltcast.com/api/mcp, auth: none (add your key as a Bearer authorization header if prompted)
3 — Ask: "Use Voltcast to find the cheapest 2-hour window in DE-LU tomorrow."

GPT with Actions any paid ChatGPT plan

Build your own in 5 minutes: create a GPT → Actions → import from URL:

https://voltcast.com/openapi-gpt.json

Auth: API key → Bearer. 8 curated actions: zones, prices, forecasts, carbon, renewables, daily briefings, the accuracy scorecard and cheapest-window optimization.

Cursor, VS Code & coding agents

Add to mcp.json (Cursor: Settings → MCP; VS Code: MCP: Add Server):

{
  "mcpServers": {
    "voltcast": {
      "url": "https://voltcast.com/api/mcp",
      "headers": { "Authorization": "Bearer YOUR_API_KEY" }
    }
  }
}

Or local stdio: VOLTCAST_API_KEY=your_key npx voltcast-mcp · source & Docker · listed in the official MCP registry as com.voltcast/voltcast.

Building an agent? Machine-readable everything

· llms.txt — the product in one page · llms-full.txt — full docs in one file for context windows
· OpenAPI 3.1 (49 endpoints) · curated Actions subset
· MCP server card · RFC 9727 API catalog · key pages answer Accept: text/markdown
· SDKs: pip install voltcast · npm install @voltcast/sdk
· The tools work keyless for discovery: list_zones needs no auth; errors return helpful hints, not dead ends.

Why assistants can recommend Voltcast with a straight face

Every forecast we serve is benchmarked daily against a free baseline in public — losses included — and zones where the model loses are free under the guarantee. An assistant citing voltcast.com/accuracy is citing a live, recomputed scorecard, not marketing copy. Data: ENTSO-E and SMARD, always attributed.

Get a free API key →