We've covered several Layer 2 sidechains before:


But today might be the fastest of them all. On top it's tightly connected to the NEAR protocol ecosystem, a PoS chain with a scalable sharding design. And of course they have a bridge to Ethereum!

What is the Aurora Chain?

Aurora Chain

Aurora accepts Ethereum-style transactions and executes them in its EVM running on NEAR. This gives Solidity developers familiar tooling, with chain-specific opcode and precompile behavior to check. Aurora is built on NEAR’s consensus and execution infrastructure; it is not an Ethereum rollup.

Users pay Aurora transaction fees in ETH, while relayers submit the underlying NEAR transactions. The Rainbow Bridge moves assets between Ethereum, NEAR and Aurora. A bridged balance is a representation of transferred value, not an extra independently spendable copy of the same funds.

See Aurora’s network and relayer documentation for the current entry points.

Why choose Aurora?

Aurora Performance

Historical context: The fee and throughput figures below are examples reported for the 2021 release, not current benchmarks or guaranteed costs. Actual fees, capacity and finality depend on the current network and workload.

  • Extremely low fees up, one example given by the team was a single ERC-20 token transfer for Ethereum being about 5.40$ (50 Gwei gas price) and only 0.01$ on Aurora. That’s more than 500x cheaper!

  • 2000+ transactions per second (more than 50x faster than ETH1.0).

  • Decentralization through DAO governance.

  • Future-proof sharding design of NEAR core infrastructure.

  • Fast finality.

How to deploy to Aurora

The example below uses legacy Truffle configuration with the documented Aurora endpoints. Truffle is archived; use a maintained toolchain for a new application and test its complete configuration.

javascript
// Legacy Truffle configuration. HDWalletProvider and mnemonic are defined by the surrounding project.
module.exports = {
  networks: {
    aurora: {
      provider: () => new HDWalletProvider(mnemonic, "https://mainnet.aurora.dev"),
      network_id: 1313161554,
    },
    aurora_testnet: {
      provider: () => new HDWalletProvider(mnemonic, "https://testnet.aurora.dev"),
      network_id: 1313161555,
    },
  },
};

You'll also need funds in the chain of course. For the testnet you can use the faucet here. For how to transfer funds from the public chain, read on.

How to onboard users to your Aurora Dapp

1. Choice of wallet

These days you have much more than just MetaMask as possible wallets to support available. Take a look at Yearn Finance for example. They are supporting 11 different wallets alone at the time of this writing.

Wallet Options
MetaMask confirmation to add Binance Smart Chain, showing chain ID 56 and a warning to verify the network details.

2. MetaMask example live in action

MetaMask supports requests to add custom EVM networks. The screenshot below is a historical Binance Smart Chain prompt, reused only to illustrate the kind of wallet confirmation a dapp can request. Its BSC name, RPC and chain ID are not Aurora settings, and PancakeSwap is not an Aurora onboarding example. Use the Aurora parameters in the code below and compare them with the official network reference.

3. How to add Aurora automatically for users

The code requests Aurora’s addition and then requests switching separately. Either request may be declined; adding a network alone does not guarantee that it becomes active. Always use the wallet’s actual chain for the dapp’s state.

javascript
// Aurora: chain ID 1313161554 (decimal).
// Testnet: chain ID 1313161555 (0x4e454153), https://testnet.aurora.dev; choose the matching settings together.
const params = [
  {
    "chainId": "0x4e454152",
    "chainName": "Aurora",
    "rpcUrls": [
      "https://mainnet.aurora.dev"
    ],
    "nativeCurrency": {
      "name": "Ether",
      "symbol": "ETH",
      "decimals": 18
    }
  }
];

try {
  await ethereum.request({ method: "wallet_addEthereumChain", params });
  // Adding a network does not guarantee that it is selected.
  await ethereum.request({
    method: "wallet_switchEthereumChain",
    params: [{ chainId: params[0].chainId }],
  });
} catch (error) {
  // The wallet may reject either request; keep the UI on its actual chain.
  console.error("Network request was not completed", error);
}

Using the Aurora Bridge

Aurora Bridge

The Rainbow Bridge supports transfers among Ethereum, NEAR and Aurora. The original “testnet only” limitation is historical. Its current documentation explains supported assets, transfer direction, confirmation steps and timing; use that workflow rather than the launch-era instructions.

Historical context: The following town-hall notice refers to July 12, 2021 and is retained as part of the original post.

Lastly, you can participate in the town hall event to ask further questions happening on July 12th. I will be updating this post with any potentially interesting new information coming from this event.