Sei

Sei Parallelized EVM L1

What You Probably Got Wrong

• Sei V2 is a parallelized EVM, NOT just a Cosmos chain. Since V2, Sei runs the EVM natively as its primary execution environment. It is not an EVM bridge, sidechain, or rollup on top of Cosmos. The EVM executes directly inside the Sei node with parallel transaction processing.
• Pointer contracts enable EVM<>CosmWasm interop. A CW20 token automatically gets a pointer ERC20 contract, and an ERC20 token can get a pointer CW20 contract. This means the same token is accessible from both execution environments without bridging or wrapping. The pointer is a lightweight proxy, not a copy.
• Associated balances let EVM addresses hold Cosmos-native tokens. Your EVM address (0x...) can hold native usei, IBC denoms, and TokenFactory tokens directly. No wrapping required. This is NOT the same as WSEI -- it is the actual native balance.
• The native DEX module is deprecated. Sei originally had a built-in order matching engine (the dex module). This is deprecated in favor of standard EVM DEXes like DragonSwap and Yaka Finance. Do NOT build against the native DEX module.
• Standard EVM tooling works. Deploy with Hardhat, Foundry, viem, ethers.js -- no custom compiler, no special flags. Sei EVM is bytecode-compatible with Ethereum. The Solidity compiler target is paris (no Shanghai-era PUSH0).
• Parallel execution requires no code changes. Sei's optimistic parallelization happens at the runtime level. Your Solidity contracts do not need any annotations or special patterns. However, contracts that touch independent storage slots parallelize better.
• Precompile contracts exist for Cosmos-native operations. Staking, governance, IBC transfers, address format conversion, and JSON parsing are all available via precompile contracts at fixed addresses. These are callable from Solidity like normal contracts.
• EVM version target is paris, not shanghai. Sei's EVM does not support the PUSH0 opcode introduced in Shanghai. Set evmVersion: "paris" in your compiler config or deployments will fail with opcode errors.

Chain Configuration

Mainnet (pacific-1)

RPC Endpoints (Mainnet)

Block Explorers

Testnet (atlantic-2)

Devnet (arctic-1)

Key Differences from Ethereum

Quick Start: viem Chain Definition

import { defineChain } from "viem";

export const sei = defineChain({
  id: 1329,
  name: "Sei",
  nativeCurrency: { name: "SEI", symbol: "SEI", decimals: 18 },
  rpcUrls: {
    default: {
      http: ["https://evm-rpc.sei-apis.com"],
      webSocket: ["wss://evm-ws.sei-apis.com"],
    },
  },
  blockExplorers: {
    default: { name: "Seitrace", url: "https://seitrace.com" },
    seistream: { name: "Seistream", url: "https://seistream.app" },
  },
});

export const seiTestnet = defineChain({
  id: 1328,
  name: "Sei Testnet",
  nativeCurrency: { name: "SEI", symbol: "SEI", decimals: 18 },
  rpcUrls: {
    default: {
      http: ["https://evm-rpc-testnet.sei-apis.com"],
      webSocket: ["wss://evm-ws-testnet.sei-apis.com"],
    },
  },
  blockExplorers: {
    default: { name: "Seitrace", url: "https://seitrace.com/?chain=atlantic-2" },
  },
  testnet: true,
});

Quick Start: Foundry Setup

# foundry.toml
[profile.default]
src = "src"
out = "out"
libs = ["lib"]
evm_version = "paris"

[rpc_endpoints]
sei = "https://evm-rpc.sei-apis.com"
sei_testnet = "https://evm-rpc-testnet.sei-apis.com"

[etherscan]
sei = { key = "${SEITRACE_API_KEY}", chain = 1329, url = "https://seitrace.com/api" }
sei_testnet = { key = "${SEITRACE_API_KEY}", chain = 1328, url = "https://seitrace.com/api?chain=atlantic-2" }

Quick Start: Hardhat Configuration

import { HardhatUserConfig } from "hardhat/config";
import "@nomicfoundation/hardhat-toolbox";

const config: HardhatUserConfig = {
  solidity: {
    version: "0.8.24",
    settings: {
      evmVersion: "paris",
      optimizer: { enabled: true, runs: 200 },
    },
  },
  networks: {
    sei: {
      url: process.env.SEI_RPC_URL || "https://evm-rpc.sei-apis.com",
      chainId: 1329,
      accounts: [process.env.PRIVATE_KEY!],
    },
    seiTestnet: {
      url: process.env.SEI_TESTNET_RPC_URL || "https://evm-rpc-testnet.sei-apis.com",
      chainId: 1328,
      accounts: [process.env.PRIVATE_KEY!],
    },
  },
  etherscan: {
    apiKey: {
      sei: process.env.SEITRACE_API_KEY!,
    },
    customChains: [
      {
        network: "sei",
        chainId: 1329,
        urls: {
          apiURL: "https://seitrace.com/api",
          browserURL: "https://seitrace.com",
        },
      },
    ],
  },
};

export default config;

Deployment

Foundry Deploy

forge create src/MyContract.sol:MyContract \
  --rpc-url https://evm-rpc.sei-apis.com \
  --private-key $PRIVATE_KEY

forge script script/Deploy.s.sol:DeployScript \
  --rpc-url https://evm-rpc.sei-apis.com \
  --broadcast \
  --slow

Hardhat Deploy

npx hardhat run scripts/deploy.ts --network sei
npx hardhat run scripts/deploy.ts --network seiTestnet

Verification

forge verify-contract <address> src/MyContract.sol:MyContract \
  --chain 1329 \
  --verifier etherscan \
  --etherscan-api-key $SEITRACE_API_KEY \
  --verifier-url https://seitrace.com/api

Parallel Execution

Sei executes EVM transactions in parallel using optimistic concurrency control. No Solidity changes needed.

1. Transactions are ordered by the consensus layer
2. Multiple threads execute transactions concurrently against an optimistic state
3. SeiDB tracks read/write sets for each transaction
4. Conflicts detected at commit time -- conflicting transactions are re-executed
5. Results committed in original transaction order (deterministic)

Parallel-Friendly Contract Design

Precompile Contracts

Sei provides precompile contracts for accessing Cosmos-native functionality from Solidity. These are callable like normal contracts but execute native chain logic.

Only CALL is supported for state-changing precompiles. DELEGATECALL and STATICCALL may not work for write operations.

Address Precompile

Address: 0x0000000000000000000000000000000000001004

Converts between EVM (0x) and Cosmos (sei1...) address formats.

interface IAddrPrecompile {
    function getSeiAddr(address evmAddr) external view returns (string memory);
    function getEvmAddr(string memory seiAddr) external view returns (address);
}

IAddrPrecompile constant ADDR = IAddrPrecompile(0x0000000000000000000000000000000000001004);

function lookupCosmosAddress(address evmAddr) external view returns (string memory) {
    return ADDR.getSeiAddr(evmAddr);
}

function lookupEvmAddress(string calldata seiAddr) external view returns (address) {
    return ADDR.getEvmAddr(seiAddr);
}

Staking Precompile

Address: 0x0000000000000000000000000000000000001005

Delegate, undelegate, and claim staking rewards from EVM contracts.

interface IStaking {
    function delegate(string memory validator) external payable returns (bool);
    function undelegate(string memory validator, uint256 amount) external returns (bool);
    function redelegate(
        string memory srcValidator,
        string memory dstValidator,
        uint256 amount
    ) external returns (bool);
}

IStaking constant STAKING = IStaking(0x0000000000000000000000000000000000001005);

function stake(string calldata validator) external payable {
    bool success = STAKING.delegate{value: msg.value}(validator);
    require(success, "Delegation failed");
}

Governance Precompile

Address: 0x0000000000000000000000000000000000001006

Vote on Cosmos governance proposals from EVM.

interface IGov {
    function vote(uint64 proposalId, int32 option) external returns (bool);
    function deposit(uint64 proposalId) external payable returns (bool);
}

Vote options: 1 = Yes, 2 = Abstain, 3 = No, 4 = NoWithVeto.

Distribution Precompile

Address: 0x0000000000000000000000000000000000001007

Claim staking rewards.

interface IDistribution {
    function withdrawDelegationRewards(string memory validator) external returns (bool);
    function setWithdrawAddress(address newAddress) external returns (bool);
}

IBC Precompile

Address: 0x0000000000000000000000000000000000001009

Transfer tokens cross-chain via IBC directly from EVM contracts.

interface IIBC {
    function transfer(
        string memory toAddress,
        string memory port,
        string memory channel,
        string memory denom,
        uint256 amount,
        uint64 revisionNumber,
        uint64 revisionHeight,
        uint64 timeoutTimestamp
    ) external returns (bool);
}

IIBC constant IBC = IIBC(0x0000000000000000000000000000000000001009);

function ibcTransfer(
    string calldata toAddress,
    string calldata channel,
    uint256 amount
) external {
    // Timeout: 10 minutes from now in nanoseconds
    uint64 timeout = uint64(block.timestamp + 600) * 1_000_000_000;
    bool success = IBC.transfer(
        toAddress,
        "transfer",
        channel,
        "usei",
        amount,
        0,
        0,
        timeout
    );
    require(success, "IBC transfer failed");
}

JSON Precompile

Address: 0x0000000000000000000000000000000000001003

Parse JSON strings on-chain. Useful for processing CosmWasm query responses in EVM.

interface IJson {
    function extractAsBytes(bytes memory input, string memory key) external view returns (bytes memory);
    function extractAsBytesList(bytes memory input, string memory key) external view returns (bytes[] memory);
    function extractAsUint256(bytes memory input, string memory key) external view returns (uint256);
}

Precompile Address Summary

Pointer Contracts

Pointer contracts are the mechanism for EVM<>CosmWasm token interoperability. They are lightweight proxy contracts that allow a token created in one execution environment to be accessed in the other.

How Pointers Work

1. A CW20 token is deployed on Sei's CosmWasm runtime
2. Anyone calls the Pointer precompile to register a pointer ERC20 for that CW20
3. The pointer ERC20 contract appears at a deterministic address
4. EVM users interact with the pointer ERC20 -- calls are forwarded to the underlying CW20
5. Balances, transfers, and approvals are mirrored across both environments

The same works in reverse: an ERC20 can get a pointer CW20.

Querying Pointer Contracts

interface IPointer {
    function getPointer(uint16 pointerType, string memory tokenId) external view returns (address, uint16, bool);
}

pointerType values:

• 0 = ERC20 pointer for a CW20 token
• 1 = ERC721 pointer for a CW721 token
• 2 = CW20 pointer for an ERC20 token
• 3 = CW721 pointer for an ERC721 token
• 4 = ERC20 pointer for a native/IBC denom

IPointer constant POINTER = IPointer(0x000000000000000000000000000000000000100b);

// Get the ERC20 address for a CW20 token
function getCW20Pointer(string calldata cw20Addr) external view returns (address) {
    (address pointerAddr, , bool exists) = POINTER.getPointer(0, cw20Addr);
    require(exists, "Pointer not registered");
    return pointerAddr;
}

// Get the ERC20 address for a native Cosmos denom
function getNativeDenomPointer(string calldata denom) external view returns (address) {
    (address pointerAddr, , bool exists) = POINTER.getPointer(4, denom);
    require(exists, "Pointer not registered");
    return pointerAddr;
}

Associated Balances

EVM addresses on Sei can hold Cosmos-native tokens (usei, IBC denoms, TokenFactory tokens) directly. These are called "associated balances" because the 0x address is associated with its corresponding sei1... address.

How It Works

1. Every EVM address has a deterministic Cosmos address (and vice versa)
2. The Address precompile converts between formats
3. When Cosmos-native tokens are sent to the sei1... address, they appear as associated balances on the 0x address
4. The Bank precompile allows EVM contracts to send these native tokens

Reading Associated Balances

import { createPublicClient, http, parseAbi } from "viem";
import { sei } from "./chains";

const client = createPublicClient({ chain: sei, transport: http() });

const bankAbi = parseAbi([
  "function balance(address account, string denom) view returns (uint256)",
  "function all_balances(address account) view returns ((uint256, string)[])",
]);

const BANK = "0x0000000000000000000000000000000000001001" as const;

const seiBalance = await client.readContract({
  address: BANK,
  abi: bankAbi,
  functionName: "balance",
  args: ["0xYourAddress", "usei"],
});

// seiBalance is in usei (6 decimals on Cosmos side)

Sending Native Tokens from EVM

interface IBank {
    function send(
        address fromAddress,
        address toAddress,
        string memory denom,
        uint256 amount
    ) external returns (bool);
    function balance(address account, string memory denom) external view returns (uint256);
}

IBank constant BANK = IBank(0x0000000000000000000000000000000000001001);

Calling CosmWasm from EVM

The Wasm precompile lets EVM contracts execute and query CosmWasm contracts.

Address: 0x0000000000000000000000000000000000001002

interface IWasm {
    function instantiate(
        uint64 codeID,
        string memory admin,
        bytes memory msg,
        string memory label,
        bytes memory coins
    ) external returns (string memory contractAddr);

    function execute(
        string memory contractAddress,
        bytes memory msg,
        bytes memory coins
    ) external returns (bytes memory response);

    function query(
        string memory contractAddress,
        bytes memory req
    ) external view returns (bytes memory response);
}

IWasm constant WASM = IWasm(0x0000000000000000000000000000000000001002);

function queryCosmWasmContract(
    string calldata contractAddr,
    bytes calldata queryMsg
) external view returns (bytes memory) {
    return WASM.query(contractAddr, queryMsg);
}

function executeCosmWasmContract(
    string calldata contractAddr,
    bytes calldata executeMsg,
    bytes calldata coins
) external returns (bytes memory) {
    return WASM.execute(contractAddr, executeMsg, coins);
}

SEI Token Decimals

SEI has different decimal representations depending on context:

When transferring between EVM and Cosmos contexts, the chain handles decimal conversion automatically. Pointer contracts and precompiles handle the 18<>6 decimal conversion internally.

Gas Optimization Tips

1. Design for parallel execution -- per-user mappings over global counters
2. Use precompiles for Cosmos operations -- cheaper than external contract calls through CosmWasm
3. Batch via multicall -- reduces per-transaction overhead
4. Set evmVersion: "paris" -- avoids PUSH0 opcode errors
5. Keep contracts under 24.576 KB -- standard EVM limit applies
6. Minimize storage writes to shared slots -- reduces parallel execution conflicts

Pre-Deployment Checklist

• evmVersion: "paris" in compiler config (no PUSH0)
• Correct chain ID (1329 mainnet / 1328 testnet)
• Account funded with SEI for gas
• Private key in environment variable, not hardcoded
• Contract size under 24.576 KB
• All Solidity follows CEI pattern (Checks-Effects-Interactions)
• bigint used for all token amounts in TypeScript
• msg.sender used for auth (never tx.origin)
• Verified on Seitrace after deployment
• Tested pointer contract interaction if using EVM<>CosmWasm interop

Additional Reference

References

• Sei Docs: https://docs.sei.io
• Sei EVM Docs: https://docs.sei.io/dev-tutorials/evm-general
• Sei Interoperability: https://docs.sei.io/dev-advanced-concepts/interoperability
• Seitrace Explorer: https://seitrace.com
• Sei GitHub: https://github.com/sei-protocol