Connecting to Base

Connect to Base mainnet or the Sepolia testnet using public RPC endpoints, your own node, or a third-party provider.

Network parameters

Base Mainnet

Parameter	Value
Network name	Base
Chain ID	`8453` (`0x2105`)
Currency	ETH
Block time	2 seconds
Flashblock interval	200ms
L1 settlement	Ethereum Mainnet
Explorer	basescan.org

Base Sepolia (testnet)

Parameter	Value
Network name	Base Sepolia
Chain ID	`84532` (`0x14a34`)
Currency	ETH (testnet)
Block time	2 seconds
L1 settlement	Ethereum Sepolia
Explorer	sepolia.basescan.org

Public RPC endpoints

Base provides public RPC endpoints for general use:

Network	HTTP Endpoint	WebSocket Endpoint
Mainnet	`https://mainnet.base.org`	`wss://mainnet.base.org`
Sepolia	`https://sepolia.base.org`	`wss://sepolia.base.org`

Connecting with common tools

curl

A raw JSON-RPC POST request returns the latest block number as a hex string.

This is the lowest-common-denominator way to talk to Base — useful for sanity-checking that an endpoint is alive.

curl -X POST https://mainnet.base.org \
  -H "Content-Type: application/json" \
  -d '{
    "method": "eth_blockNumber",
    "params": [],
    "id": 1,
    "jsonrpc": "2.0"
  }'

cast (Foundry)

Foundry’s cast wraps every standard JSON-RPC method behind a clean CLI. Point it at any Base endpoint with --rpc-url.

cast block-number --rpc-url https://mainnet.base.org

cast balance 0xYourAddress --rpc-url https://mainnet.base.org

cast chain-id --rpc-url https://mainnet.base.org

ethers.js

JsonRpcProvider is the standard ethers entry point. It works against any Base endpoint — public, your own node, or a provider.

import { JsonRpcProvider } from "ethers";

const provider = new JsonRpcProvider("https://mainnet.base.org");

const blockNumber = await provider.getBlockNumber();
console.log("Current block:", blockNumber);

const balance = await provider.getBalance("0xYourAddress");
console.log("Balance:", balance.toString(), "wei");

viem

viem ships chain definitions for both Base networks. createPublicClient selects the right RPC defaults automatically.

import { createPublicClient, http } from "viem";
import { base, baseSepolia } from "viem/chains";

const client = createPublicClient({
  chain: base,
  transport: http(),
});

const blockNumber = await client.getBlockNumber();
console.log("Current block:", blockNumber);

const testnetClient = createPublicClient({
  chain: baseSepolia,
  transport: http(),
});

MetaMask / wallet configuration

To add Base to a wallet manually:

Field	Mainnet	Sepolia
Network Name	Base	Base Sepolia
RPC URL	`https://mainnet.base.org`	`https://sepolia.base.org`
Chain ID	`8453`	`84532`
Currency Symbol	ETH	ETH
Block Explorer URL	`https://basescan.org`	`https://sepolia.basescan.org`

Running your own node

For production, running your own Base node gives full control over rate limits, latency, and data availability.

Quick start

The fastest path is the pre-built Docker image:

docker pull ghcr.io/base/base-reth-node:latest

docker run -d \
  --name base-node \
  -p 8545:8545 \
  -p 8546:8546 \
  -p 30303:30303 \
  -v base-data:/data \
  ghcr.io/base/base-reth-node:latest \
  --http \
  --http.addr 0.0.0.0 \
  --http.port 8545 \
  --http.api eth,net,web3,txpool \
  --ws \
  --ws.addr 0.0.0.0 \
  --ws.port 8546

For full instructions:

Building from source — compile the node binary.
Running the node — configuration and startup.
Docker — containerized deployment.
Node deployment — production deployment guide.

Node sync modes

Mode	Description	Disk usage	Sync time
Full	Executes all transactions from genesis.	High	Days
Snap	Downloads state snapshots, then follows chain tip.	Moderate	Hours

JSON-RPC interface

Base nodes expose the standard Ethereum JSON-RPC interface. The following namespaces are available:

Standard namespaces

Namespace	Description
`eth`	Core Ethereum methods — blocks, transactions, state queries, gas estimation.
`net`	Network information — peer count, version, listening status.
`web3`	Utility methods — client version, SHA3.
`txpool`	Transaction pool inspection (see Transaction Pool).
`debug`	Debug methods — trace transactions, get raw block data (enable with `--http.api debug`).

Base-specific namespaces

Namespace	Description
`base`	Base-specific methods including metering (see Metering RPC).

Commonly used methods

Method	Description
`eth_blockNumber`	Returns the latest block number.
`eth_getBlockByNumber`	Returns block data by number or tag.
`eth_getBlockByHash`	Returns block data by hash.
`eth_getTransactionByHash`	Returns a transaction by hash.
`eth_getTransactionReceipt`	Returns a transaction receipt.
`eth_getBalance`	Returns account balance.
`eth_getTransactionCount`	Returns account nonce.
`eth_call`	Executes a call without creating a transaction.
`eth_estimateGas`	Estimates gas for a transaction.
`eth_sendRawTransaction`	Submits a signed transaction.
`eth_getCode`	Returns contract bytecode.
`eth_getStorageAt`	Returns storage value at a given position.
`eth_getLogs`	Returns logs matching a filter.
`eth_chainId`	Returns the chain ID.

Flashblocks support

The "pending" block tag is supported across applicable methods when flashblocks are enabled. See Flashblocks RPC for details on querying preconfirmed state.

Troubleshooting

Common issues

Issue	Cause	Solution
`429 Too Many Requests`	Rate limit exceeded on public endpoint.	Reduce request frequency or run your own node.
Connection refused on port 8545	Node HTTP RPC not enabled.	Start the node with `--http` and `--http.addr 0.0.0.0`.
Empty response for `eth_getLogs`	Block range too large.	Reduce the `fromBlock`/`toBlock` range (max ~2000 blocks per query).
Wrong chain ID	Connected to wrong network.	Verify the RPC URL matches the intended network.
`nonce too low`	Transaction nonce already used.	Use `"pending"` tag with `eth_getTransactionCount` for the latest nonce.