RPC method

eth_blockNumber on Blast

Supported on SwiftNodes

Everything below was measured on 2026-10-13 by calling eth_blockNumber on Blast through the same endpoint customers use, and is re-measured weekly.

What eth_blockNumber does

Returns the number of the most recent block the node has, as a hex string. It is the cheapest way to tell whether a node is keeping up and the usual starting point for polling a chain.

eth_blockNumber on Blast: what we measured

Head block when measured41,542,533 (0x279e385)
Age of that block when read1 s
Average block time (last 1,000 blocks)2.0 s
Median gap between newHeads over WebSocket2.0 s
"safe" behind the head38 blocks (about 76 s)
"finalized" behind the head743 blocks (about 25 min)

What this means for polling

At 2.0 s per block, a one-second poll returns a new number on roughly one call in 2. Polling at the block time keeps you current without wasting requests.

The number eth_blockNumber returns is the newest block, which can still change in a reorg. On Blast, "finalized" was 743 blocks (about 25 min) behind it and "safe" 38 blocks behind. Use eth_getBlockByNumber("finalized") when you need a height that will not change.

Compared with other chains

Measured by the gap between WebSocket headers, Blast has the 28th fastest block cadence of the 40 chains we measure.

Example request

curl -s https://rpc.swiftnodes.io/rpc/blast?key=YOUR_API_KEY \
  -X POST -H "Content-Type: application/json" \
  -d '{"jsonrpc":"2.0","id":1,"method":"eth_blockNumber","params":[]}'
import { createPublicClient, http } from "viem";

const client = createPublicClient({
  transport: http("https://rpc.swiftnodes.io/rpc/blast?key=YOUR_API_KEY"),
});

const head = await client.getBlockNumber(); // bigint

// Follow the chain: poll about once per block (2.0 s on Blast)
const unwatch = client.watchBlockNumber({
  pollingInterval: 2000,
  onBlockNumber: (n) => console.log("new head", n),
});

Other methods on Blast

eth_blockNumber on other chains

Frequently asked questions

Does Blast support eth_blockNumber?

Yes. eth_blockNumber answered on the SwiftNodes Blast endpoint when our weekly probe called it through the customer path (2026-10-13).

How fast are blocks on Blast?

About 2.0 s per block, averaged over recent blocks (measured 2026-10-13).

How often should I poll eth_blockNumber on Blast?

About once per block, every 2.0 s. Faster polling mostly returns the same number.

Blast endpoints, live block height and WebSocket status are on the Blast RPC page.

One key covers every chain we serve, and SwiftNodes has a free tier.