Solana TX submit API

Our API provides blazing-fast transaction propagation on Solana network, as well as additional features, such as MEV protection.

Authentication options

• via HTTP header X-TOKEN: your_token

• via HTTP query argument api_key=your_token

Submit transaction via API

Example request with curl

curl -XPOST -H 'X-TOKEN: your_token' \
https://sol-rpc.rpcfast.net/?tx_submit_mode=fastest -d '
{
	"jsonrpc": "2.0",
	"method": "sendTransaction",
	"params": [
		"your_signed_transaction",
		{
			"encoding": "base64"
		}
	],
	"id": 100
}'

Query parameters

Parameter	Description	Allowed values	Required
tx_submit_mode	Transaction submission mode	fastest,
mev_protect,
balanced	no
tip_amount	Tip amount in Lamports	min. 1000000	no, required only for tx_submit_mode
fallback	Whether to fallback to default submission mode	true, false	no

Transaction submission modes

Default mode

The default transaction submission mode is used when you omit the tx_submit_mode argument.

Even in default mode, you'll get faster transaction propagation speed compared to standard RPC providers.

Paid modes

These transaction submission modes require an additional tip (min. 0.001 SOL) for every request.

Mode	Description
fastest	Transaction is send to staked RPCs allowing for the fastest propagation
mev_protect	Enable front-running protection in cost of slower transaction propagation
balanced	Balanced mode between speed and front-running protection

Tip for paid submission modes

Tip should be specified in lamports (1 SOL = 1,000,000,000 lamports).

The minimum required tip amount is 0.001 SOL or 1,000,000 Lamports.

Setting a higher tip will increase propagation speed.

To check most up-to-date recommended tip amount, consider subscribing to websocket endpoint.

Transaction priority fee

Prioritization Fees are an optional fee, priced in micro-lamports per Compute Unit (e.g. small amounts of SOL), appended to transactions to make them economically compelling for validator nodes to include in blocks on the network.

Please check official Solana documentation on how to add priority fee to your transaction.

To receive up-to-date priority fees consider subscribing to priority fee stream websocket.

Pricing

• Base tariff includes 1000 CU, where 1 CU = 0.001 SOL = 1,000,000 lamports.

• If you need bigger amount of CU, please contact us.

When you reach your CU limit, paid transaction submission modes become unavailable and we will respond with an error, like this:

{
	"jsonrpc": "2.0",
	"id": 1,
	"error": {
		"code": -32600,
		"message": "sendTransaction mode 'fastest' is unavailable, please contact RPCFast support."
	}
}

If you still want to forward transaction but fallback to default submission mode, you can specify fallback=true query argument.