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RPC uses the same API keys as the REST API. Send your key in the X-API-Key header on every request.
Authenticated RPC request
curl "https://rpc.radion.app" \
  -H "X-API-Key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"jsonrpc":"2.0","id":1,"method":"eth_blockNumber","params":[]}'
Use the key value as it is. Do not put Bearer in front of it. RPC needs a paid plan: starter, pro, or enterprise. A valid key on the free plan is rejected. You can check the plan on a key with GET /auth/me on the REST API. See REST Authentication.

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What errors mean

CaseResponse
You sent no key401 Unauthorized
The key is wrong or turned off401 Unauthorized
The key is valid but on the free plan403 Forbidden
Errors come back as JSON-RPC error objects.
Free plan rejected
{
  "jsonrpc": "2.0",
  "id": 1,
  "error": { "code": -32000, "message": "RPC requires a paid plan" }
}

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Good habits

  • Keep secret keys (sk_...) on your server, never in a browser.
  • Use a different key for each app or environment when you can.
  • Make a new key if you think an old one leaked.
Last modified on July 7, 2026