Add Base Sepolia to MetaMask

Add Base Sepolia to MetaMask (Complete, Fast, and Safe Guide)

Base Sepolia is the public testnet for the Base network (built on the OP Stack). It’s the best place to experiment with dApps, try deployments, or learn L2 flows without risking real funds. This guide gives you a reliable, copy-paste setup (RPC + Chain ID), one-click alternatives, how to verify everything, where to find test ETH, and troubleshooting steps.

What you need

Option A — Add Base Sepolia to MetaMask manually (recommended)

Open MetaMask and follow these steps:

  1. Click the network selector at the top of MetaMask (it might say “Ethereum Mainnet”).
  2. Click Add network (or Add network manually on some versions).
  3. Paste the exact values below, then save.
Network name: Base Sepolia
New RPC URL: https://sepolia.base.org
Chain ID: 84532
Currency symbol: ETH
Block explorer URL: https://sepolia.basescan.org

Once you save, MetaMask should switch to Base Sepolia automatically. If it doesn’t, open the network dropdown and select it.

Verify your connection

  1. Confirm the top of MetaMask says Base Sepolia.
  2. Copy your wallet address and search it on the Base Sepolia explorer: https://sepolia.basescan.org. If the page loads your address (even with 0 balance), your network is configured correctly.

Option B — Add Base Sepolia with one click (Chainlist)

Prefer a one-click method? Use Chainlist to push the network into MetaMask automatically:

  1. Open: https://chainlist.org/chain/84532
  2. Click Connect Wallet → Add to MetaMask.
  3. Approve the prompts in MetaMask.

It’s still a good idea to compare the values in MetaMask with the manual block above to ensure nothing is off.

Why Base Sepolia?

  • Zero real risk: All funds are test ETH, so you can experiment freely.
  • Fast and inexpensive: Test transactions and UI flows quickly.
  • OP Stack ecosystem: Base is part of the Superchain vision, so testing here mirrors modern L2 design.

Get test ETH for Base Sepolia

To send transactions or deploy contracts, you’ll need test ETH on Base Sepolia (has no real value). Faucets come and go, but these are commonly used:

Tip: If a faucet is down or rate-limited, try again later or search for “Base Sepolia faucet” from official/dev sources. Never pay for test ETH.

Common actions after adding Base Sepolia

  • Send a test transaction: After funding, send a tiny amount of test ETH to another wallet to confirm gas and block times feel right.
  • Deploy a sample contract: Use your favorite framework (Hardhat/Foundry/Remix) and point RPC to https://sepolia.base.org with Chain ID 84532.
  • Bookmark the explorer: https://sepolia.basescan.org for quick transaction, contract, and address lookups.

Troubleshooting & FAQs

MetaMask says “Chain ID already exists.”

You may have added a duplicate entry before. Go to MetaMask → Networks, find the existing Base Sepolia entry, and either Edit it to match the values above or Delete and add again.

I added the network, but the RPC fails or my balance won’t load.

  • Double-check the RPC endpoint: https://sepolia.base.org (no typos, no trailing spaces).
  • Public endpoints can rate-limit; wait 30–60 seconds and try again.
  • Open the explorer and search your address: https://sepolia.basescan.org. If the explorer loads normally, the network is reachable.

How do I confirm I’m on Base Sepolia (not mainnet)?

Check both the name and Chain ID in MetaMask. Base Mainnet uses Chain ID 8453. Base Sepolia uses 84532. The testnet explorer is sepolia.basescan.org (vs. basescan.org for mainnet).

Can I bridge from Ethereum Sepolia to Base Sepolia?

Yes, but only testnet to testnet (Sepolia → Base Sepolia). Make sure both ends are testnets. Never send mainnet funds to a testnet network.

Gas token and decimals?

Gas on Base Sepolia is paid in ETH, 18 decimals, the same symbol and decimals as mainnet, but it’s test ETH with no real value.

Where can I verify the official settings?

Always cross-check with the Base docs or developer resources when in doubt:
https://docs.base.org

Copy block (keep for your notes)

Base Sepolia (MetaMask)
RPC URL: https://sepolia.base.org
Chain ID: 84532
Currency symbol: ETH
Block Explorer: https://sepolia.basescan.org

Quick recap

  1. Open MetaMask → Add network manually.
  2. Paste: RPC https://sepolia.base.org · Chain ID 84532 · Symbol ETH · Explorer https://sepolia.basescan.org.
  3. Switch to Base Sepolia and verify with the explorer.
  4. Grab test ETH from a reputable faucet if you plan to send transactions.

That’s it. You’re set up on Base Sepolia and ready to build, test, and iterate safely.

Useful links