Get the latest finalized Solana blockhash instantly

Return the most recent finalized blockhash and its last valid block height for client-side transaction construction. Public endpoint, no API key.

Every Solana transaction needs a recent blockhash. This endpoint returns the latest finalized hash plus its lastValidBlockHeight so you can build and submit transactions client-side without running your own RPC node. Free, no API key required, cheap to call in a loop.

Why agents use this

• You need it for every tx. Any transaction built more than ~90 seconds after the blockhash was fetched will expire. Refresh often.
• lastValidBlockHeight prevents ghost failures. Compare against current slot to know if your tx window is still open.
• No RPC infra required. Devs building agents from scratch can construct + submit transactions with just this and a wallet.
• Devnet + mainnet from the same endpoint. Add ?network=devnet for testing.

Use cases

• Client-side tx builder. Web app or CLI that constructs Solana transactions, fetches blockhash from the gateway, signs locally.
• Blockhash refresh in a sniper bot. Cache blockhash for 30 seconds, then refresh. Never submit an expired tx.
• Tx expiry monitor. Watch lastValidBlockHeight on your queued transactions and re-sign the ones nearing expiry.
• Onboarding health check. Users hit blockhash to verify their gateway integration works before committing to a paid plan.
• Wallet SDK bootstrap. Custom mobile wallet? Point it here for blockhash so you don’t have to bundle an RPC dependency.

Recipe: fresh-blockhash cache

blockhash-cache.ts

const GATEWAY = "https://solana-pulse-gateway-1021990235790.us-central1.run.app";

let cache: { blockhash: string; lastValidBlockHeight: number; at: number } | null = null;

export async function getFreshBlockhash(maxAgeMs = 30_000) {
  if (cache && Date.now() - cache.at < maxAgeMs) return cache;

  const res = await fetch(`${GATEWAY}/api/solana/blockhash`);
  const data = await res.json();
  cache = { ...data, at: Date.now() };
  return cache;
}

Free endpoint. Pair with Optimal Fee to build fully-configured transactions with two gateway calls and no RPC of your own.