What is the Ethereum Sepolia RPC URL?

The Ethereum Sepolia RPC URL with BoltRPC is https://endpoints.boltrpc.io/rpc/YOUR_API_KEY/ethereum-sepolia. Replace YOUR_API_KEY with your API key from dashboard.boltrpc.io. The chain ID is 11155111.

What is the Sepolia testnet used for?

Sepolia is Ethereum's recommended general-purpose testnet for dApp development and smart contract testing. It is used for deploying and testing smart contracts, running integration test suites, testing DeFi protocols and validating application-layer contracts before deployment to Ethereum mainnet. For validator and staking infrastructure testing, use Hoodi Testnet instead.

What is the Sepolia chain ID?

The Ethereum Sepolia Testnet chain ID is 11155111. Use this value when configuring wallets, ethers.js providers, viem clients, or any tool that requires a chain ID for network identification.

How do I get test ETH for Sepolia?

Use a Sepolia faucet such as sepoliafaucet.com to request test ETH. Test ETH on Sepolia has no real-world value and is only used for development and testing. Most faucets require a mainnet ETH balance or social verification to prevent abuse.

How do I add the Sepolia testnet to MetaMask?

Open MetaMask, go to Settings, then Networks, then Add Network and enter: Network Name: BoltRPC Ethereum Sepolia, RPC URL: https://endpoints.boltrpc.io/rpc/YOUR_API_KEY/ethereum-sepolia, Chain ID: 11155111, Currency Symbol: ETH, Block Explorer: https://sepolia.etherscan.io.

What is the difference between Sepolia and Hoodi?

Sepolia is the general-purpose Ethereum testnet for dApp development and smart contract testing. Hoodi is designed for validator and staking infrastructure testing: deposit contract testing, withdrawal flows and validator client development. Build dApps on Sepolia. Build staking infrastructure on Hoodi.

Why use a paid RPC provider for a testnet?

Public testnet RPCs drop connections during congestion, return stale data and impose strict rate limits. For development teams with automated integration test suites and CI/CD pipelines, a flaky testnet endpoint causes false failures and wasted debugging time. BoltRPC's testnet access is included alongside mainnet access at no extra cost.

Can I use the same API key for Sepolia and Ethereum mainnet?

Yes. BoltRPC uses one API key across all networks. Your Sepolia endpoint and your Ethereum mainnet endpoint use the same API key and the same endpoint format. When promoting from testnet to mainnet, you only change the network slug from ethereum-sepolia to ethereum.

Ethereum Sepolia Testnet RPC Endpoint

Test on Sepolia the way you will run mainnet: a dedicated testnet endpoint for CI pipelines, deployment rehearsals and integration suites.

chain id · 11155111JSON-RPC 2.0WebSocket

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LIVE LATENCY

13ms

LIVE

gateway round-trip · sampled every second

IN PRODUCTION AT Chainlink

Your endpoint, ready in one line.

Drop this URL into your RPC client, HTTP library or wallet config. No SDK install required.

HTTPS

https://endpoints.boltrpc.io/rpc/YOUR_API_KEY/ethereum-sepolia

WEBSOCKET

wss://endpoints.boltrpc.io/ws/YOUR_API_KEY/ethereum-sepolia

Replace YOUR_API_KEY with your API key. Get a free key →

Pick your stack.

Copy-paste examples for the libraries you already use. Swap the API key, hit run.

import { ethers } from "ethers";

const provider = new ethers.JsonRpcProvider(
  "https://endpoints.boltrpc.io/rpc/YOUR_API_KEY/ethereum-sepolia"
);

// Confirm you are on Sepolia (chain ID 11155111)
const network = await provider.getNetwork();
console.log(network.chainId); // 11155111n

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

const client = createPublicClient({
  chain: sepolia,
  transport: http("https://endpoints.boltrpc.io/rpc/YOUR_API_KEY/ethereum-sepolia"),
});

const blockNumber = await client.getBlockNumber();
console.log(blockNumber);

curl -X POST \
  "https://endpoints.boltrpc.io/rpc/YOUR_API_KEY/ethereum-sepolia" \
  -H "Content-Type: application/json" \
  -d '{"jsonrpc":"2.0","method":"eth_blockNumber","params":[],"id":1}'

Connect to the Ethereum Sepolia Testnet with BoltRPC’s reliable RPC infrastructure. Start your free 2-week trial and access Sepolia alongside Ethereum mainnet from the same provider, with testnet RPC parity to your production setup.

Chain at a Glance


Chain ID	11155111
Protocol	PoS testnet
Block time	~12 s
Native token	ETH (test)
Finality	~2 epochs (~12.8 min)
EVM compatible	Yes

What Sepolia is Built For

Sepolia is Ethereum’s recommended general-purpose testnet for smart contract development and dApp testing. It replaced Ropsten as the primary testnet for application developers and has been stable and well-maintained since Ethereum’s transition to proof-of-stake. Sepolia is the right choice for teams building dApps, ERC-20 tokens, NFT contracts, DeFi protocols, or any application-layer smart contract that needs to be validated before deployment to Ethereum mainnet.

The Sepolia testnet closely mirrors Ethereum mainnet in terms of EVM behaviour, transaction lifecycle and JSON-RPC API surface. Smart contracts that pass testing on Sepolia behave as expected on mainnet. That makes it the standard staging environment for application developers across the Ethereum ecosystem.

Sepolia is explicitly not designed for validator testing or staking infrastructure. Teams that need to test deposit contracts, withdrawal flows, or validator client software should use Hoodi Testnet instead. The distinction matters: Sepolia’s validator set is permissioned and small, so it does not replicate the full Ethereum consensus layer for staking purposes. For dApp development, however, that permissioned validator set is an advantage: it keeps the chain stable and predictable, which is exactly what application teams need during development and integration testing.

Use Sepolia when your workflow includes any of the following: deploying and testing smart contracts before mainnet, running automated integration test suites against a live EVM chain, testing protocol interactions, running dApp staging environments, verifying contract behaviour with real transaction flows, or developing tooling that interacts with Ethereum’s JSON-RPC API. Sepolia test ETH has no real-world value and is freely available from faucets, which means your development team can run transactions at volume without any cost.

For teams building on multiple Ethereum-compatible networks, using BoltRPC for Sepolia alongside your Ethereum mainnet connection means one API key, one endpoint format and one provider to manage across your entire stack.

Built for teams that ship on Ethereum.

Free trial access with mainnet-parity infrastructure

BoltRPC's 2-week free trial includes testnet access. Your Sepolia workflow uses the same endpoint format, the same API key and the same infrastructure quality as your Ethereum mainnet setup. No separate accounts or configurations for testnet.

Built for application development workflows

Sepolia is the standard testnet for Ethereum smart contract development and dApp testing. BoltRPC gives your Sepolia endpoint the same reliability as your production connections. Automated test suites, staging environments and CI/CD pipelines that rely on Sepolia get consistent, stable RPC access.

Stable testnet infrastructure for CI/CD

Public testnet RPCs drop connections, hit rate limits and lag behind the chain tip. BoltRPC gives your Sepolia workflows the same stability as your mainnet setup. No broken test pipelines from unreliable endpoints.

Mirror your mainnet setup

Use BoltRPC on Sepolia and Ethereum mainnet from the same provider. One API key, one endpoint format, one configuration to manage. When you promote from Sepolia to mainnet, only the endpoint slug changes.

WebSocket support for event-driven testing

Subscribe to Sepolia testnet events via WebSocket at wss://endpoints.boltrpc.io/ws/YOUR_API_KEY/ethereum-sepolia. Useful for integration test suites that need real-time block confirmation events, contract event subscriptions, or pending transaction monitoring during development.

Globally distributed infrastructure, ISO/IEC 27001:2022 certified

BoltRPC's endpoint infrastructure is operated by Matrixed.Link, certified to ISO/IEC 27001:2022. For teams in regulated industries or organizations with vendor security requirements, this matters even for testnet access as the same infrastructure serves both testnet and mainnet workloads.

Full JSON-RPC coverage.

Every standard Ethereum method you would expect. Archive-only methods are available on request for qualifying plans.

STANDARD9

eth_calleth_sendRawTransactioneth_getBalanceeth_blockNumbereth_getTransactionReceipteth_getLogseth_estimateGaseth_getCode

javascript
import { ethers } from "ethers";

const provider = new ethers.JsonRpcProvider(
  "https://endpoints.boltrpc.io/rpc/YOUR_API_KEY/ethereum-sepolia"
);

const wallet = new ethers.Wallet(process.env.PRIVATE_KEY, provider);

// Deploy contract
const factory = new ethers.ContractFactory(abi, bytecode, wallet);
const contract = await factory.deploy();
await contract.waitForDeployment();

const address = await contract.getAddress();
console.log("Deployed to Sepolia:", address);

// Verify deployment
const code = await provider.getCode(address);
console.log("Contract deployed:", code.length > 2);

Ethereum, explained.

Common questions about connecting to Ethereum over BoltRPC.

Ask a question →Read the docs

: The Ethereum Sepolia RPC URL with BoltRPC is https://endpoints.boltrpc.io/rpc/YOUR_API_KEY/ethereum-sepolia. Replace YOUR_API_KEY with your API key from dashboard.boltrpc.io. The chain ID is 11155111.
: Sepolia is Ethereum's recommended general-purpose testnet for dApp development and smart contract testing. It is used by teams deploying and testing smart contracts, running integration test suites, testing DeFi protocols, verifying NFT contracts and validating any application-layer smart contract before deployment to Ethereum mainnet. For validator and staking infrastructure testing, use Hoodi Testnet instead.
: The Ethereum Sepolia Testnet chain ID is 11155111. Use this value when configuring wallets, ethers.js providers, viem clients, or any tool that requires a chain ID for network identification. When connecting via MetaMask, enter 11155111 as the chain ID.
: Use a Sepolia faucet such as sepoliafaucet.com to request test ETH. Test ETH on Sepolia has no real-world value and is only used for development and testing. Most faucets require a mainnet ETH balance or social verification to prevent abuse.
: Open MetaMask, go to Settings, then Networks, then Add Network and enter: Network Name: BoltRPC Ethereum Sepolia, RPC URL: https://endpoints.boltrpc.io/rpc/YOUR_API_KEY/ethereum-sepolia, Chain ID: 11155111, Currency Symbol: ETH, Block Explorer: https://sepolia.etherscan.io.
: Sepolia is the general-purpose Ethereum testnet for dApp development and smart contract testing. Hoodi is designed specifically for validator and staking infrastructure testing: deposit contract testing, withdrawal flows and validator client development. If you are building a dApp, use Sepolia. If you are building staking or validator infrastructure, use Hoodi. The two testnets serve different audiences and should not be used interchangeably.
: Public testnet RPCs are shared and often unreliable: they drop connections during congestion, return stale data and impose strict rate limits. For development teams running automated integration test suites and CI/CD pipelines, a flaky testnet endpoint causes false failures and wasted debugging time. BoltRPC's testnet access is included in all plans alongside mainnet access, so there is no extra cost for reliable Sepolia RPC.
: Yes. BoltRPC uses one API key across all networks. Your Sepolia endpoint and your Ethereum mainnet endpoint use the same API key and the same endpoint format. When promoting from testnet to mainnet, you only change the network slug in your endpoint URL from ethereum-sepolia to ethereum.

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