eth_subscribe on BNB Smart Chain
Everything below was measured on 2026-10-13 by calling eth_subscribe on BNB Smart Chain through the same endpoint customers use, and is re-measured weekly.
What eth_subscribe does
Opens a subscription over WebSocket: newHeads pushes each new block header, logs pushes matching events, and newPendingTransactions pushes mempool transaction hashes where the node exposes them. It replaces polling, and it only works over WebSocket, not HTTP.
eth_subscribe on BNB Smart Chain: what we measured
| newHeads | supported |
|---|---|
| First header after subscribing | 477 ms |
| Median gap between headers | 418 ms |
| Headers in 15 seconds | 33 |
| logs | supported |
| newPendingTransactions | supported |
What this means on BNB Smart Chain
Headers pushed over WebSocket are not identical to eth_getBlockByNumber over HTTP on BNB Smart Chain. Only the HTTP block has totalDifficulty, size, milliTimestamp, withdrawals. Fetch the block over HTTP if you need those fields.
Subscriptions end when the connection drops. Reconnect with backoff and, after reconnecting, fetch the blocks you missed with eth_getBlockByNumber.
Example request
wscat -c "wss://rpc.swiftnodes.io/ws/bsc?key=YOUR_API_KEY"
> {"jsonrpc":"2.0","id":1,"method":"eth_subscribe","params":["newHeads"]}import { createPublicClient, webSocket } from "viem";
const client = createPublicClient({
transport: webSocket("wss://rpc.swiftnodes.io/ws/bsc?key=YOUR_API_KEY", { reconnect: true }),
});
const unwatch = client.watchBlocks({
onBlock: (block) => console.log(block.number, block.hash),
});
// Events from one contract, pushed as they are mined
client.watchContractEvent({ address: token, abi: erc20Abi, eventName: "Transfer", onLogs: (logs) => console.log(logs) });Other methods on BNB Smart Chain
- eth_blockNumberSupported
- 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_getLogsSupported
- eth_getBlockReceiptsSupported
- eth_feeHistorySupported
- eth_getProofSupported
- eth_createAccessListSupported
- debug_traceCallSupported
- trace_blockSupported
- trace_transactionNot available
eth_subscribe on other chains
- Ethereum
- Base
- Arbitrum
- Optimism
- Polygon
- 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
- BOB
- 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 BNB Smart Chain support eth_subscribe?
Yes. eth_subscribe answered on the SwiftNodes BNB Smart Chain endpoint when our weekly probe called it through the customer path (2026-10-13).
Does BNB Smart Chain support WebSocket subscriptions?
Yes. newHeads and logs worked through wss://rpc.swiftnodes.io/ws/bsc on 2026-10-13.
Can I watch the BNB Smart Chain mempool?
newPendingTransactions is supported.
BNB Smart Chain endpoints, live block height and WebSocket status are on the BNB Smart Chain RPC page.
One key covers every chain we serve, and SwiftNodes has a free tier.