BNB Smart Chain RPC Endpoint and Chain Settings

BNB Smart Chain Chain Settings at a Glance

BNB Smart Chain (formerly Binance Smart Chain, BSC) is an EVM-compatible blockchain. Developers interact with it using standard JSON-RPC methods, but the network parameters differ from Ethereum. The mainnet chain ID is 56, represented as 0x38 in hexadecimal. The testnet chain ID is 97, represented as 0x61. Both networks use BNB as the native gas token, but testnet uses tBNB.

Adding BNB Smart Chain to a Wallet

Most EVM wallets, including MetaMask and Rabby, allow manual network addition. Use the mainnet values from the table above. If you have a private OnFinality endpoint, replace the public URL with your assigned HTTPS or WebSocket URL.

• Open the wallet's Settings or Networks menu.
• Choose Add network or Add custom network.
• Enter Network name: BNB Smart Chain.
• Set RPC URL to https://bsc-dataseed.bnbchain.org or your OnFinality endpoint.
• Set Chain ID to 56.
• Set Currency symbol to BNB.
• Set Block explorer URL to https://bscscan.com.
• Save and switch to the network.

Verifying the Endpoint with eth_chainId and curl

Before sending transactions, confirm you are connected to BNB Smart Chain mainnet. Use eth_chainId: a response of 0x38 is mainnet; 0x61 is testnet. If you receive 0x1 (Ethereum) or another chain ID, stop and fix your configuration.

Example curl request against the OnFinality public endpoint:

``bash curl -X POST https://bnb.api.onfinality.io/public \ -H "Content-Type: application/json" \ --data '{"jsonrpc":"2.0","method":"eth_chainId","params":[],"id":1}' ``

Expected response:

``json {"jsonrpc":"2.0","id":1,"result":"0x38"} ``

You can also check block height with eth_blockNumber. For JavaScript applications, use ethers.js or viem:

ethers.js example:

``javascript const { ethers } = require("ethers"); const provider = new ethers.JsonRpcProvider("https://bnb.api.onfinality.io/public"); const network = await provider.getNetwork(); console.log("Chain ID:", Number(network.chainId)); // 56 ``

viem example:

``javascript import { createPublicClient, http } from 'viem'; import { bsc } from 'viem/chains'; const client = createPublicClient({ chain: bsc, transport: http('https://bnb.api.onfinality.io/public') }); const chainId = await client.getChainId(); console.log(chainId); // 56 ``

Public Endpoint Limitations and Rate-Limit Behavior

The official BNB Smart Chain public endpoints are shared infrastructure. According to the BNB developer documentation, the listed public mainnet endpoints have a rate limit of 10,000 requests per 5 minutes per IP, and eth_getLogs is disabled on those listed mainnet endpoints to protect node performance. These limitations apply to the official public list, not necessarily to OnFinality's public endpoint.

OnFinality's supplied BNB mainnet network configuration states that its public endpoint at https://bnb.api.onfinality.io/public provides EVM-compatible HTTPS and WebSocket RPC, archive support, and trace/API access. However, specific rate limits for that endpoint are not published in this guide; treat it as a testing and prototyping endpoint unless your plan details otherwise.

For production applications, relying solely on free public endpoints is risky. You need predictable throughput, WebSocket subscriptions, archive data, and full log support. Managed RPC services like OnFinality's offer these capabilities; see /networks/bnb for current details.

• Official public endpoints may throttle at ~10K requests/5min.
• eth_getLogs is disabled on some official mainnet endpoints.
• Free endpoints are shared; performance can degrade during network congestion.
• OnFinality public endpoint supports WebSocket, archive, and trace but production plans may be required for higher limits.

Troubleshooting Common BNB Smart Chain RPC Failures

Even with correct network settings, developers encounter issues. Here are common failures and fixes.

• **Wrong chain ID:** eth_chainId returns 0x1, 0x5, or 0x61 when you expect mainnet. Check your RPC URL and chain configuration; never send mainnet transactions to a testnet or Ethereum address.
• **eth_getLogs disabled or method not found:** Some public endpoints disable log queries. Use a provider that supports eth_getLogs or subscribe to logs via WebSocket.
• **429 rate limit exceeded:** Your app is exceeding the public endpoint's request limit. Implement client-side throttling, caching, or move to a managed endpoint.
• **Connection timeouts:** The endpoint may be overloaded or distant. Try an alternate official mirror or a geographically closer provider. Consider WebSocket for real-time needs.
• **Nonce too low:** The transaction nonce is incorrect. Use eth_getTransactionCount with 'pending' to track the next nonce.
• **Node health:** If your provider supports eth_health, you can use it to check node status; not all endpoints implement this method.

Evaluating Endpoint Providers for Production

When your dApp outgrows public endpoints, compare providers on the criteria below. This is not a vendor ranking; the right choice depends on your workload. Use the OnFinality BNB network page (/networks/bnb) to see current endpoint options, and the provider comparison guide at /rpc-assistant/bnb-chain-rpc-provider for a structured evaluation path.

BNB Smart Chain Testnet Endpoint Guide

Use testnet for development, staging, and contract testing. The testnet chain ID is 97 (0x61), and the native token is tBNB. Official testnet endpoints include https://bsc-testnet-dataseed.bnbchain.org. OnFinality provides a public testnet endpoint at https://bnb-testnet.api.onfinality.io/public, which is useful for testing EVM-compatible HTTPS and WebSocket connections.

Request tBNB from a BNB testnet faucet before deploying contracts. For more details on testnet configuration and OnFinality's testnet service, see /rpc-assistant/bnb-chain-testnet-endpoint.

• Testnet RPC: https://bsc-testnet-dataseed.bnbchain.org or https://bnb-testnet.api.onfinality.io/public
• Chain ID: 97 (0x61)
• Currency: tBNB
• Block explorer: https://testnet.bscscan.com

Moving from Public RPC to a Production Endpoint

To move beyond public endpoints, sign up for a managed RPC service. OnFinality provides BNB Smart Chain RPC access with options for archive data, WebSocket, and trace/API. Create a private endpoint by following the instructions on the BNB network page (/networks/bnb). Your private URL will include a project-specific identifier; use placeholders in your configuration, such as:

`` https://your-project.onfinality.io/... ``

Do not hardcode API keys in client-side code. Use environment variables and restrict access by referrer or IP where possible. For BSC API method reference, see /rpc-assistant/bsc-api. For dedicated node options, review the BNB network hub and provider comparison at /rpc-assistant/bnb-chain-rpc-provider.

• Replace the public URL with your private endpoint.
• Update the chain ID, currency, and explorer settings if needed.
• Monitor request volume and errors in the provider dashboard.
• Keep a fallback endpoint for high availability.

Frequently Asked Questions