RPC method

eth_blockNumber on Plasma

Supported on SwiftNodes

Everything below was measured on 2026-10-13 by calling eth_blockNumber on Plasma 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 Plasma: what we measured

Head block when measured34,954,090 (0x2155b6a)
Age of that block when read1 s
Average block time (last 1,000 blocks)1.0 s
"safe" behind the head1 blocks (about 1 s)
"finalized" behind the head1 blocks (about 1 s)

What this means for polling

At 1.0 s per block, a one-second poll returns a new number on roughly every call. Polling at the block time keeps you current without wasting requests.

"finalized" trailed the head by only 1 block on Plasma, so blocks become final almost immediately.

Example request

curl -s https://rpc.swiftnodes.io/rpc/plasma?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/plasma?key=YOUR_API_KEY"),
});

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

// Follow the chain: poll about once per block (1.0 s on Plasma)
const unwatch = client.watchBlockNumber({
  pollingInterval: 1000,
  onBlockNumber: (n) => console.log("new head", n),
});

Other methods on Plasma

eth_blockNumber on other chains

Frequently asked questions

Does Plasma support eth_blockNumber?

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

How fast are blocks on Plasma?

About 1.0 s per block, averaged over recent blocks (measured 2026-10-13).

How often should I poll eth_blockNumber on Plasma?

About once per block, every 1.0 s. Faster polling mostly returns the same number.

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

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