🚦 Rate Limiting: Infura, Alchemy, QuickNode

Send multiple RPC calls in one HTTP request. Instead of 10 separate requests (10 credits), send 1 batched request (1 credit). Reduces usage by 90% for read-heavy apps.

const batch = [
  { method: 'eth_getBalance', params: [...] },
  { method: 'eth_call', params: [...] }
];
await provider.send(batch);

Block data never changes. Cache blocks, receipts, and logs in Redis/database. First request hits RPC, subsequent requests hit cache. Saves 99% of requests for historical data.

const cached = await redis.get(blockNumber);
if (cached) return cached;
const block = await provider.getBlock(blockNumber);
await redis.set(blockNumber, block);

For real-time data (new blocks, pending txs), use eth_subscribe via WebSocket. Node pushes updates to you. No polling needed. Saves 99% of requests vs polling every second.

const ws = new WebSocket(wssUrl);
ws.send({ method: 'eth_subscribe', 
  params: ['newHeads'] });
// Receive block updates automatically

Query multiple contracts in one eth_call. Multicall aggregates 100 calls into 1. Popular for token prices, balances. Used by Uniswap, 1inch. Saves 99% of requests.

const multicall = new Multicall(provider);
const results = await multicall.aggregate([
  token1.balanceOf(wallet),
  token2.balanceOf(wallet), // 100 more
]);