Why isn't Monad Testnet in MetaMask's dropdown by default?

MetaMask only ships a default list of major chains and their popular testnets. New testnets like Monad's are added through the custom-network flow until they are widely adopted.

What if the RPC fails when I try to add the network?

MetaMask validates the RPC by calling eth_chainId. If the public RPC is rate-limited, the call can fail. Wait a minute and try again, or use a dedicated RPC provider.

Is it safe to add a custom network to MetaMask?

Adding a network does not give the network any access to your wallet. The risk comes from interacting with malicious contracts on the network, not from the network itself. Only sign transactions from dapps you trust.

How do I switch back to Ethereum or another chain?

Click the network selector dropdown in MetaMask and pick the chain you want. Adding Monad Testnet does not remove or affect any other network in your wallet.

How to Add Monad Testnet to MetaMask

4 min read · Updated 2026-04-27

Monad Testnet is not a default network in any wallet. Before you can use a Monad dapp, your wallet needs to know about chain ID 10143 and the public RPC endpoint. This guide covers three ways to add it: a one-click prompt from PuddleSwap, the manual MetaMask flow, and the equivalent steps for Rabby, Frame, and Rainbow.

Chain details you need

Whichever method you use, you will provide some or all of these values:

Network name: Monad Testnet
Chain ID: 10143
Native currency symbol: MON
RPC URL: https://testnet-rpc.monad.xyz
Block explorer URL: https://testnet.monadscan.com

Method 1: One-click from PuddleSwap

The fastest path: open PuddleSwap and connect your wallet. If your wallet is on the wrong chain, PuddleSwap triggers your wallet's network-switch prompt automatically. Approve it, and your wallet adds Monad Testnet with the right values pre-filled. No copy-pasting required.

This works for any wallet that supports wallet_addEthereumChain, which covers MetaMask, Rabby, Frame, Rainbow, and most modern injected wallets.

Method 2: Add manually in MetaMask

If you prefer to add the network without connecting to a dapp first:

Open MetaMask and click the network selector at the top-left.
Click "Add a custom network" or "Add network" then "Add a network manually."
Paste the chain details from the section above.
Save. Monad Testnet appears in your network list and is selected.

MetaMask validates the chain ID against the RPC: it pings the RPC, asks for eth_chainId, and refuses to save if the response does not match the chain ID you entered. If you see a chain-mismatch error, recheck that the RPC URL and chain ID are correct.

Method 3: Rabby, Frame, and Rainbow

Rabby: Rabby auto-detects custom chains when a dapp triggers wallet_addEthereumChain, so Method 1 works. To add manually, open Rabby > Settings > Networks > Add Custom Network with the same chain details.

Frame: Open the Frame app > Chains tab > Add Chain. Provide name, chain ID, RPC, and currency symbol. Frame is desktop-only and works well with hardware wallets.

Rainbow: Recent versions of the Rainbow mobile app support custom networks. Open Rainbow > Settings > Networks > Add Custom Network. Older versions may need a wallet update first.

Troubleshooting

RPC fails or times out: The public RPC at testnet-rpc.monad.xyz can rate-limit during peak load. Wait a minute and retry, or switch to a dedicated RPC provider for sustained calls.
Chain ID mismatch: MetaMask refuses to add a network when the RPC responds with a different chain ID than what you entered. Both should say 10143.
Network already exists: If you previously added Monad Testnet with a stale RPC URL, MetaMask blocks duplicate chain IDs. Delete the old entry first, then re-add.
Hardware wallet not signing: Some hardware wallets need a firmware update to recognize new chain IDs. Check the latest firmware for your device.

What to do after adding the network

Get some test MON from a faucet (see How to Get Test MON), then try a swap on PuddleSwap to confirm everything works. If you have never used a testnet DEX, see How to Swap Tokens on Monad Testnet.

Open PuddleSwap to trigger the one-click add flow, or read What is Monad Testnet? for chain background.

FAQ

Why isn't Monad Testnet in MetaMask's dropdown by default?: MetaMask only ships a default list of major chains and their popular testnets. New testnets like Monad's are added through the custom-network flow until they are widely adopted.
What if the RPC fails when I try to add the network?: MetaMask validates the RPC by calling eth_chainId. If the public RPC is rate-limited, the call can fail. Wait a minute and try again, or use a dedicated RPC provider.
Is it safe to add a custom network to MetaMask?: Adding a network does not give the network any access to your wallet. The risk comes from interacting with malicious contracts on the network, not from the network itself. Only sign transactions from dapps you trust.
How do I switch back to Ethereum or another chain?: Click the network selector dropdown in MetaMask and pick the chain you want. Adding Monad Testnet does not remove or affect any other network in your wallet.