Read at one block

const block = await request({
  method: "eth_getBlockByNumber",
  params: ["latest", false],
});
if (!block?.hash) throw new Error("Block unavailable");

const at = { blockHash: block.hash, requireCanonical: true };
const [balance, nonce] = await Promise.all([
  request({ method: "eth_getBalance", params: [address, at] }),
  request({ method: "eth_getTransactionCount", params: [address, at] }),
]);

console.log({ blockHash: block.hash, balance, nonce });

​

Essential limits

• Providers must support block-hash selectors and retain the requested state. Lasso preserves the hash through retries.
• Lasso sends block-hash state reads only to archival providers, because a hash’s age is unknown before dispatch. In RPC Core, a chain with no provider declared archival rejects them with archive_required; on Lasso Cloud, a profile without one fails them instead of reaching a provider that may lack the state.
• requireCanonical: true asks the provider to reject a block it knows was removed from the canonical chain. It does not guarantee finality or prove execution correctness.
• If a read fails and you choose a new block, repeat all related reads. Do not mix results from different hashes.