RPC method

eth_sendRawTransaction on Flare

Supported on SwiftNodes

Everything below was measured on 2026-10-13 by calling eth_sendRawTransaction on Flare through the same endpoint customers use, and is re-measured weekly.

What eth_sendRawTransaction does

Submits a signed transaction to the network and returns its hash. The node checks the signature, chain ID, nonce and balance first, and returns an error string instead of a hash when any check fails, which is the text your app has to handle.

Errors Flare returns, word for word

We submitted three transactions that must fail, signed by a new, empty key (nothing was spent). These are the messages your app receives in those situations.

EIP-1559 transfer from an empty account	insufficient funds for gas * price + value: balance 0, tx cost 27300000000021001, overshot 27300000000021001
Legacy transaction signed without a chain ID (pre-EIP-155)	only replay-protected (EIP-155) transactions allowed over RPC
Truncated bytes ("0x02f8")	rlp: value size exceeds available input length

How to read them

"insufficient funds" means the balance cannot cover value + gas limit × max fee per gas.

Flare's nodes refuse transactions without a chain ID ("only replay-protected (EIP-155) transactions allowed over RPC"), so old signing code that omits it fails here.

Send the same signed bytes again only if you never got a hash back: a second submission of an accepted transaction returns an "already known" style error, not a second transaction, and a transaction with the same nonce but a higher fee replaces it.

Example request

curl -s https://rpc.swiftnodes.io/rpc/flare?key=YOUR_API_KEY \
  -X POST -H "Content-Type: application/json" \
  -d '{"jsonrpc":"2.0","id":1,"method":"eth_sendRawTransaction","params":["0x02f8..."]}'

import { createPublicClient, http } from "viem";

const client = createPublicClient({
  transport: http("https://rpc.swiftnodes.io/rpc/flare?key=YOUR_API_KEY"),
});

try {
  const hash = await client.sendRawTransaction({ serializedTransaction: signed });
  const receipt = await client.waitForTransactionReceipt({ hash });
} catch (e) {
  const msg = String(e?.details ?? e?.message);
  if (/insufficient funds/i.test(msg)) { /* ask the user to top up */ }
  else if (/nonce too low|already known/i.test(msg)) { /* already sent: look up by hash */ }
  else throw e;
}

Other methods on Flare

eth_sendRawTransaction on other chains

Frequently asked questions

Does Flare support eth_sendRawTransaction?

Yes. eth_sendRawTransaction answered on the SwiftNodes Flare endpoint when our weekly probe called it through the customer path (2026-10-13).

Does Flare accept transactions without a chain ID?

No. It answered "only replay-protected (EIP-155) transactions allowed over RPC".

Why does Flare return "insufficient funds" from eth_sendRawTransaction?

The sender cannot pay value plus gas limit × maxFeePerGas. Fund the account, lower the value, or lower maxFeePerGas.

Flare endpoints, live block height and WebSocket status are on the Flare RPC page.

One key covers every chain we serve, and SwiftNodes has a free tier.