Solana Priority Fee API: Smart Transaction Fee Estimation

import { Transaction, SystemProgram, ComputeBudgetProgram } from "@solana/web3.js";
import bs58 from "bs58";

// 1. Build your transaction (without priority fee)
const transaction = new Transaction();
const transferIx = SystemProgram.transfer({
  fromPubkey: senderKeypair.publicKey,
  toPubkey: recipientPublicKey,
  lamports: 1000000, // 0.001 SOL
});
transaction.add(transferIx);

// 2. Set required fields and serialize
transaction.recentBlockhash = (await connection.getLatestBlockhash()).blockhash;
transaction.feePayer = senderKeypair.publicKey;
const serializedTx = bs58.encode(transaction.serialize());

// 3. Get priority fee estimate
const response = await fetch("https://mainnet.helius-rpc.com/?api-key=YOUR_API_KEY", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({
    jsonrpc: "2.0",
    id: "1",
    method: "getPriorityFeeEstimate",
    params: [{
      transaction: serializedTx,
      options: { 
        priorityLevel: "Medium",
        recommended: true 
      }
    }]
  })
});

const result = await response.json();
const priorityFee = result.result.priorityFeeEstimate;

// 4. Add priority fee and send
transaction.instructions = []; // Reset
transaction.add(ComputeBudgetProgram.setComputeUnitPrice({ microLamports: priorityFee }));
transaction.add(transferIx);
transaction.recentBlockhash = (await connection.getLatestBlockhash()).blockhash;
transaction.sign(senderKeypair);

import requests
import base58
from solana.transaction import Transaction
from solana.system_program import transfer, TransferParams

# 1. Build and serialize your transaction
# (transaction building code here)
serialized_tx = base58.b58encode(transaction.serialize()).decode('utf-8')

# 2. Get priority fee estimate
response = requests.post(
    "https://mainnet.helius-rpc.com/?api-key=YOUR_API_KEY",
    json={
        "jsonrpc": "2.0",
        "id": "1",
        "method": "getPriorityFeeEstimate",
        "params": [{
            "transaction": serialized_tx,
            "options": {
                "priorityLevel": "Medium",
                "recommended": True
            }
        }]
    }
)

result = response.json()
priority_fee = result["result"]["priorityFeeEstimate"]
print(f"Recommended priority fee: {priority_fee} micro-lamports")

# 3. Rebuild transaction with priority fee and send

curl -X POST "https://mainnet.helius-rpc.com/?api-key=YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "jsonrpc": "2.0",
    "id": "1",
    "method": "getPriorityFeeEstimate",
    "params": [{
      "transaction": "SERIALIZED_TRANSACTION_BASE58",
      "options": {
        "priorityLevel": "Medium",
        "recommended": true
      }
    }]
  }'