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GenLayer Testnets

Add GenLayer Testnets to Your Wallet — MetaMask, OKX, Rabby, Trust Wallet

Testnet
Chain ID: 4221·Symbol: GEN

GenLayer Testnets is an EVM-compatible blockchain with Chain ID 4221 and native token GEN. This page lets you add GenLayer Testnets to MetaMask, Rabby Wallet, OKX Wallet or Trust Wallet in one click — no manual Chain ID or RPC entry required.

RPC Endpoints
https://zksync-os-testnet-genlayer.zksync.dev

Block Explorer

GenLayer Testnets Explorer

What is GenLayer Testnets?

GenLayer Testnets is an EVM (Ethereum Virtual Machine) compatible blockchain network. Any EVM wallet — MetaMask, Rabby, OKX Wallet, Trust Wallet, Coinbase Wallet — can connect and transact on GenLayer Testnets once you add the network configuration.

Why do you need to add GenLayer Testnets to your wallet?

MetaMask and most wallets only come pre-configured with Ethereum Mainnet. To transact, swap tokens, or use dApps on GenLayer Testnets, you need to add the network first. Entering an incorrect Chain ID or RPC can put your assets at risk. Use the "Add to wallet" button above — data sourced directly from chainid.network, the canonical Ethereum chain registry.

How to add GenLayer Testnets to your wallet

  1. 1

    Click Add to wallet

    Press the "Add to wallet" button above. MetaMask, OKX Wallet, Rabby Wallet or Trust Wallet will show a popup asking you to confirm adding the GenLayer Testnets network.

  2. 2

    Confirm in your wallet

    Your wallet shows the GenLayer Testnets network details: Chain ID 4221, native token GEN. Verify the Chain ID is correct, then click "Approve" or "Add Network".

  3. 3

    Switch to the new network

    After confirming, your wallet automatically switches to GenLayer Testnets. You can start transacting right away — you will need GEN to pay gas fees.

GenLayer Testnets network technical details

To add manually, go to Settings → Networks → Add Network in MetaMask (or your wallet's equivalent) and enter the details below:

NameGenLayer Testnets
Chain ID4221
Native tokenGEN
Decimals18
RPC Endpointhttps://zksync-os-testnet-genlayer.zksync.dev
Block Explorerhttps://zksync-os-testnet-genlayer.explorer.zksync.dev

Important notice

  • •Always verify Chain ID 4221 before confirming — attackers sometimes create fake networks with similar names but different Chain IDs
  • •You need GEN tokens in your wallet to pay gas fees for transactions on GenLayer Testnets
  • •Data on this page is sourced from chainid.network — the community-verified Ethereum chain registry
  • •If the "Add to wallet" button doesn't work, your wallet may not support wallet_addEthereumChain — add the network manually using the details below

Frequently asked questions

Is it safe to add GenLayer Testnets to MetaMask?▾
Yes, if you use the "Add to wallet" button on this page. Data is sourced from chainid.network — the community-audited Ethereum registry. Adding a network does not expose your private key or grant any permissions to the dApp.
What is GenLayer Testnets Chain ID?▾
The Chain ID of GenLayer Testnets is 4221. This unique number identifies the network and prevents MetaMask and other EVM wallets from mixing up transactions across different chains.
Do I need GEN tokens to use GenLayer Testnets?▾
Yes. Every transaction on GenLayer Testnets requires GEN to pay gas fees. You can purchase GEN on exchanges and bridge it to GenLayer Testnets, or use a faucet if this is a testnet.
What is the GenLayer Testnets RPC endpoint?▾
An RPC endpoint is the server address your wallet uses to communicate with the GenLayer Testnets blockchain — sending transactions, reading balances, and checking state. One popular GenLayer Testnets RPC is https://zksync-os-testnet-genlayer.zksync.dev. This page shows live latency for each RPC so you can pick the fastest one.
My wallet says GenLayer Testnets already exists when I click Add — what do I do?▾
That's completely normal. If GenLayer Testnets is already in your wallet, it will simply switch to that network instead of adding a duplicate — no error or conflict.
I added GenLayer Testnets but the network won't load — what's wrong?▾
The most common cause is a broken or overloaded RPC endpoint. Your wallet uses RPC to connect to the blockchain — if the RPC is down, the network won't load even if it was added correctly. Fix: copy a different RPC from the list above (prefer green low-latency ones), then go to Settings → Networks in your wallet and replace the old RPC with the new one. Watch the tutorial video above for step-by-step instructions on updating your RPC.