An API key, drawn as a clearance card: it identifies you to the relay and carries your rate limit.

API keys and authentication

API keys are optional. You can submit transactions without an API key. Providing one enables rate tracking, transaction history, and the stake-scaled rate limit on your key.

Without API Key

javascript

const response = await fetch("https://fra.fastrelay.sh/v1/sendTx", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({
    tx: "BASE64_ENCODED_TRANSACTION",
    simulate: false
  })
});

With API Key (Header)

javascript

const response = await fetch("https://fra.fastrelay.sh/v1/sendTx", {
  method: "POST",
  headers: {
    "Content-Type": "application/json",
    "x-api-key": "YOUR_API_KEY"
  },
  body: JSON.stringify({
    tx: "BASE64_ENCODED_TRANSACTION",
    simulate: false
  })
});

With API Key (Query Parameter)

javascript

const response = await fetch("https://fra.fastrelay.sh/v1/sendTx?api-key=YOUR_API_KEY", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({
    tx: "BASE64_ENCODED_TRANSACTION",
    simulate: false
  })
});