eth_blockNumber on BOB
Everything below was measured on 2026-10-13 by calling eth_blockNumber on BOB 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 BOB: what we measured
| Head block when measured | 39,517,205 (0x25afc15) |
|---|---|
| Age of that block when read | 2 s |
| Average block time (last 1,000 blocks) | 2.0 s |
| "safe" behind the head | 218 blocks (about 7 min) |
| "finalized" behind the head | 2,011 blocks (about 67 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 BOB, "finalized" was 2,011 blocks (about 67 min) behind it and "safe" 218 blocks behind. Use eth_getBlockByNumber("finalized") when you need a height that will not change.
Example request
curl -s https://rpc.swiftnodes.io/rpc/bob?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/bob?key=YOUR_API_KEY"),
});
const head = await client.getBlockNumber(); // bigint
// Follow the chain: poll about once per block (2.0 s on BOB)
const unwatch = client.watchBlockNumber({
pollingInterval: 2000,
onBlockNumber: (n) => console.log("new head", n),
});Other methods on BOB
- eth_chainIdSupported
- eth_getBalanceSupported
- eth_getBlockByNumberSupported
- eth_getTransactionByHashSupported
- eth_getTransactionReceiptSupported
- eth_callSupported
- eth_estimateGasSupported
- eth_gasPriceSupported
- eth_maxPriorityFeePerGasSupported
- eth_sendRawTransactionSupported
- eth_getTransactionCountSupported
- eth_getCodeSupported
- eth_subscribeNot available
- eth_getLogsSupported
- eth_getBlockReceiptsSupported
- eth_feeHistorySupported
- eth_getProofSupported
- eth_createAccessListSupported
- debug_traceCallSupported
- trace_blockSupported
- trace_transactionNot available
eth_blockNumber on other chains
- Ethereum
- Base
- Arbitrum
- Optimism
- Polygon
- BNB Smart Chain
- Avalanche
- Sonic
- Linea
- Scroll
- zkSync Era
- Blast
- Mantle
- Gnosis
- Celo
- Berachain
- Monad
- Unichain
- Kaia
- PulseChain
- World Chain
- Ronin
- Abstract
- ApeChain
- MegaETH
- Fantom
- Lisk
- Hemi
- X Layer
- Plasma
- Fraxtal
- Zora
- Story
- Soneium
- Sei
- Hyperliquid
- Taiko
- Morph
- Ink
- Katana
- Ethereum Classic
- opBNB
- Mode
- Flare
- Core
- Chiliz
- Telos EVM
- Tempo
- Cronos
- Manta Pacific
- Shibarium
- Boba Network
- Arbitrum Nova
- Immutable zkEVM
Frequently asked questions
Does BOB support eth_blockNumber?
Yes. eth_blockNumber answered on the SwiftNodes BOB endpoint when our weekly probe called it through the customer path (2026-10-13).
How fast are blocks on BOB?
About 2.0 s per block, averaged over recent blocks (measured 2026-10-13).
How often should I poll eth_blockNumber on BOB?
About once per block, every 2.0 s. Faster polling mostly returns the same number.
BOB endpoints, live block height and WebSocket status are on the BOB RPC page.
One key covers every chain we serve, and SwiftNodes has a free tier.