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Harmony Mainnet Shard 3

Add Harmony Mainnet Shard 3 to Your Wallet — MetaMask, OKX, Rabby, Trust Wallet

Chain ID: 1666600003·Symbol: ONE

Harmony Mainnet Shard 3 is an EVM-compatible blockchain with Chain ID 1666600003 and native token ONE. This page lets you add Harmony Mainnet Shard 3 to MetaMask, Rabby Wallet, OKX Wallet or Trust Wallet in one click — no manual Chain ID or RPC entry required.

RPC Endpoints
https://api.s3.t.hmny.io

Block Explorer

Harmony Block Explorer

What is Harmony Mainnet Shard 3?

Harmony Mainnet Shard 3 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 Harmony Mainnet Shard 3 once you add the network configuration.

Why do you need to add Harmony Mainnet Shard 3 to your wallet?

MetaMask and most wallets only come pre-configured with Ethereum Mainnet. To transact, swap tokens, or use dApps on Harmony Mainnet Shard 3, 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 Harmony Mainnet Shard 3 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 Harmony Mainnet Shard 3 network.

  2. 2

    Confirm in your wallet

    Your wallet shows the Harmony Mainnet Shard 3 network details: Chain ID 1666600003, native token ONE. 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 Harmony Mainnet Shard 3. You can start transacting right away — you will need ONE to pay gas fees.

Harmony Mainnet Shard 3 network technical details

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

NameHarmony Mainnet Shard 3
Chain ID1666600003
Native tokenONE
Decimals18
RPC Endpointhttps://api.s3.t.hmny.io
Block Explorerhttps://explorer.harmony.one/blocks/shard/3

Important notice

  • •Always verify Chain ID 1666600003 before confirming — attackers sometimes create fake networks with similar names but different Chain IDs
  • •You need ONE tokens in your wallet to pay gas fees for transactions on Harmony Mainnet Shard 3
  • •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 Harmony Mainnet Shard 3 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 Harmony Mainnet Shard 3 Chain ID?▾
The Chain ID of Harmony Mainnet Shard 3 is 1666600003. This unique number identifies the network and prevents MetaMask and other EVM wallets from mixing up transactions across different chains.
Do I need ONE tokens to use Harmony Mainnet Shard 3?▾
Yes. Every transaction on Harmony Mainnet Shard 3 requires ONE to pay gas fees. You can purchase ONE on exchanges and bridge it to Harmony Mainnet Shard 3, or use a faucet if this is a testnet.
What is the Harmony Mainnet Shard 3 RPC endpoint?▾
An RPC endpoint is the server address your wallet uses to communicate with the Harmony Mainnet Shard 3 blockchain — sending transactions, reading balances, and checking state. One popular Harmony Mainnet Shard 3 RPC is https://api.s3.t.hmny.io. This page shows live latency for each RPC so you can pick the fastest one.
My wallet says Harmony Mainnet Shard 3 already exists when I click Add — what do I do?▾
That's completely normal. If Harmony Mainnet Shard 3 is already in your wallet, it will simply switch to that network instead of adding a duplicate — no error or conflict.
I added Harmony Mainnet Shard 3 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.