Migrate Your EVM dApp to Sei

Step-by-step checklist for teams that already run on another EVM chain and want to redeploy on Sei, including environment prep, contract migration, liquidity planning, and chain-specific guidance for Ethereum, Arbitrum, Base, Polygon, and Avalanche.

Sei offers full EVM bytecode compatibility plus instant finality and sub-second blocks. This guide distills what product teams need to do when they already run on Polygon, Base, Ethereum, Arbitrum, Avalanche or another EVM chain and want to bring your dApp stack to Sei.

Why Migrate to Sei?

• 400ms block times – 30× faster than Ethereum, 2-5× faster than most L2s
• ~100 MGas/s throughput – 20× higher than Ethereum mainnet
• Instant finality (~400 ms) – No waiting for confirmations or safe/finalized states
• Parallelized execution – Higher throughput without code changes
• Full EVM compatibility – Deploy your existing Solidity contracts unchanged

Chain Comparison Overview

Before diving into migration steps, understand how Sei compares to your source chain:

Feature	Sei	Ethereum	Arbitrum	Base	Polygon PoS	Avalanche C-Chain
Chain ID	1329	1	42161	8453	137	43114
Block Time	400 ms	~12 s	~250 ms	~2 s	~2 s	~2 s
Finality	Instant (~400 ms)	~15 min (finalized)	~7 days (L1 settlement)	~7 days (L1 settlement)	~5 s (Heimdall v2)	~1 s
Gas Limit	12.5 M	60M	32M	375M	45M	Dynamic
Per-Tx Gas Cap	12.5 M	~16.7 M	32 M	~25 M	45 M	Dynamic
Native Token	SEI	ETH	ETH	ETH	POL (MATIC)	AVAX
Parallel Execution	Yes	No	No	No	No	No
Base Fee Burn	No (100% to validators)	Yes (EIP-1559)	Yes	Yes	Yes	Yes
EVM Version	Pectra (w/o blobs)	Fusaka	Fusaka	Pectra	Pectra	Cancun

Chain-Specific Migration Guides

Select your source chain to see specific migration considerations:

Ethereum

Migrating from Ethereum Mainnet

Key Differences:

Aspect	Ethereum	Sei	Migration Impact
Block time	~12 seconds	400 ms	Reduce deadline buffers in DEX swaps by 30×
Finality	~15 min for finalized	Instant (~400 ms)	Remove confirmation polling logic
Gas limit	~16.7M per TX (EIP-7825)	12.5 M per block/TX	Split large batch deployments
Fee model	EIP-1559 with burn	EIP-1559 different params	Update fee estimation UIs
Pending state	Yes	No	Remove pending transaction logic

What to Update:

1. Time-based logic: If your contracts use block timestamps for deadlines, reduce timeouts proportionally. A 30-minute deadline on Ethereum (~150 blocks) should be ~45 seconds on Sei (~112 blocks).

2. Confirmation requirements: Remove any logic that waits for multiple confirmations or checks “safe” vs “finalized” states—Sei has instant finality.

3. Gas estimation: Sei’s parallelized execution can slightly vary gas estimates. Add a modest buffer (10-15%) to your gasLimit calculations.

4. Fee UI: Simplify your frontend—you can use a single gasPrice input instead of maxFeePerGas / maxPriorityFeePerGas.

// Before (Ethereum EIP-1559)
const tx = await contract.method({
  maxFeePerGas: ethers.parseUnits('50', 'gwei'),
  maxPriorityFeePerGas: ethers.parseUnits('2', 'gwei')
});

// After (Sei - simplified)
const tx = await contract.method({
  gasPrice: ethers.parseUnits('50', 'gwei') // Sei minimum gas price is 50 gwei (live on mainnet — query with eth_gasPrice)
});

Sei enforces a 50 gwei minimum gas price; transactions below this are rejected by the mempool. Query the live value with eth_gasPrice (returns base fee + suggested tip).

5. PREVRANDAO/DIFFICULTY: If you use these for any randomness, integrate a VRF oracle instead—Sei’s values are derived from block time, not true randomness.

Arbitrum

Migrating from Arbitrum

Key Differences:

Aspect	Arbitrum	Sei	Migration Impact
Architecture	Optimistic Rollup (L2)	L1	No L1 data availability concerns
Finality	~7 days for L1 settlement	Instant (~400 ms)	Simplify withdrawal flows
Sequencer	Centralized sequencer	Decentralized validators	No sequencer downtime risk
Block time	~250 ms	400 ms	Slightly slower, but with true finality
L1 gas	Pays L1 data costs	No L1 dependency	Simpler fee structure

What to Update:

1. Remove L1 interactions: Any logic that posts data to or reads from Ethereum L1 should be removed or replaced with Sei-native alternatives.

2. Sequencer assumptions: Remove any sequencer uptime checks or fallback logic—Sei uses decentralized consensus.

3. Withdrawal delays: If your protocol has 7-day withdrawal windows for “L1 finality,” you can remove these—Sei settles instantly.

4. ArbOS precompiles: Replace any Arbitrum-specific precompiles:

// Arbitrum-specific (remove)
// import { ArbSys } from "@arbitrum/nitro-contracts/src/precompiles/ArbSys.sol";
// uint256 blockNum = ArbSys(0x64).arbBlockNumber();

// Sei equivalent
uint256 blockNum = block.number; // Standard EVM

5. Cross-chain messaging: Replace Arbitrum’s native bridge with LayerZero V2 for omnichain connectivity.

Base

Migrating from Base

Key Differences:

Aspect	Base	Sei	Migration Impact
Architecture	OP Stack Rollup (L2)	L1	No L1 data availability concerns
Finality	~7 days for L1 settlement	Instant (~400 ms)	Simplify withdrawal flows
Block time	~2 seconds	400 ms	5× faster block production
Sequencer	Coinbase-operated	Decentralized validators	No single point of failure
EIP-4844 blobs	Supported	Not supported	Remove blob transaction logic

What to Update:

1. Remove blob transactions: Sei doesn’t support EIP-4844 blob transactions. If you’re using them for data availability, store data differently or use Sei’s native mechanisms.

2. OP Stack precompiles: Remove any Optimism/Base-specific precompile calls:

// Base-specific (remove)
// L1Block(0x4200000000000000000000000000000000000015).number();

// Use standard EVM on Sei
uint256 blockNum = block.number;

3. Fault proof assumptions: Remove any logic that accounts for the 7-day challenge period—Sei has instant finality.

4. Sequencer fee logic: Base has a separate L1 data fee component. On Sei, fees are simpler: Gas Used × Gas Price.

5. Coinbase Wallet integrations: Update wallet connection logic to use Sei network parameters:

// Update network config
const seiMainnet = {
  chainId: '0x531', // 1329 in hex
  chainName: 'Sei',
  nativeCurrency: { name: 'Sei', symbol: 'SEI', decimals: 18 },
  rpcUrls: ['https://evm-rpc.sei-apis.com'],
  blockExplorerUrls: ['https://seiscan.io']
};

Polygon

Migrating from Polygon PoS

Key Differences:

Aspect	Polygon PoS	Sei	Migration Impact
Native token	POL (MATIC)	SEI	Update all token references
Block time	~2 seconds	400 ms	5× faster blocks
Finality	~5 s (Heimdall v2)	Instant (~400 ms)	Remove finality delay handling
Checkpoints	Periodic to Ethereum	None	Simpler architecture
Reorgs	Possible (rare)	Never	Remove reorg handling

What to Update:

1. Token references: Replace all MATIC/POL references with SEI:

// Before (Polygon)
// IERC20(0x0d500B1d8E8eF31E21C99d1Db9A6444d3ADf1270).transfer(...); // WMATIC

// After (Sei) - use native SEI or wrapped version
// Check ecosystem contracts for canonical WSEI address

2. Checkpoint logic: Remove any logic that waits for Polygon checkpoints to Ethereum—Sei has instant finality.

3. Heimdall/Bor assumptions: Remove any Polygon-specific validator or sidechain logic.

4. Reorg handling: You can safely remove block reorganization handling code—Sei’s consensus prevents reorgs.

5. Gas price oracles: Polygon’s gas prices can spike significantly. Sei’s fees are more stable due to higher throughput:

// Polygon - needed aggressive gas price management
const gasPrice = await provider.getGasPrice();
const boostedPrice = gasPrice.mul(120).div(100); // 20% buffer

// Sei - simpler approach works
const gasPrice = await provider.getGasPrice(); // Usually sufficient as-is

6. Bridge integrations: Replace Polygon Bridge with LayerZero or other Sei-supported bridges.

Avalanche

Migrating from Avalanche C-Chain

Key Differences:

Aspect	Avalanche C-Chain	Sei	Migration Impact
Native token	AVAX	SEI	Update all token references
Block time	~2 seconds	400 ms	5× faster blocks
Finality	~1 second	Instant (~400 ms)	Similar, slightly faster
Subnets	Supported	N/A	Remove subnet logic
Gas limit	Dynamic (post-Octane)	12.5 M	Large tx headroom varies; benchmark deployments

What to Update:

1. Token references: Replace AVAX with SEI:

// Before (Avalanche)
// IERC20(0xB31f66AA3C1e785363F0875A1B74E27b85FD66c7).transfer(...); // WAVAX

// After (Sei)
// Use native SEI or check ecosystem contracts for WSEI

2. Subnet interactions: If your dApp uses Avalanche Subnets, you’ll need to redesign that architecture for Sei’s single-chain model or use cross-chain messaging.

3. Avalanche-specific precompiles: Remove C-Chain precompile calls:

// Avalanche-specific (remove)
// INativeMinter(0x0200000000000000000000000000000000000001).mintNativeCoin(...)

// Use standard EVM patterns on Sei

4. Gas limit adjustments: Avalanche now uses a dynamic gas model after Octane, while Sei has a fixed 12.5M block/tx cap. If you have large transactions, benchmark them on Sei and split them when needed:

// If deploying large contracts, batch by gas
const MAX_GAS_PER_BATCH = 11_500_000; // Leave buffer under 12.5M

5. TWAP calculations: Both chains have fast blocks, but adjust your observation windows if migrating oracle logic:

// Avalanche: 1 hour = ~1800 blocks
// Sei: 1 hour = ~9000 blocks
uint32 constant TWAP_PERIOD = 9000; // Adjust for Sei's block time

Step 1: Evaluate Compatibility

Revisit the Divergence from Ethereum doc and confirm every assumption your contracts/frontends make still holds.

Dimension	Sei EVM	Practical Effect
Block time	400 ms	Faster TX inclusion → smaller deadline buffers and quicker price oracles
Finality	Instant (~400 ms)	No separate “safe/latest” commitment levels to poll
Gas limit	12.5M gas + 21 MB byte limit	Batch contract deployments by 12.5M gas blocks
Base fee	Dynamic but never burned	Validators receive 100% of fees
Execution	Parallelized EVM	No changes to your Solidity code are necessary
Address format	Dual (0x + sei1…)	Same private key derives both addresses

Features Requiring Attention:

• Pending state: Sei doesn’t have pending state — transactions are either included or not
• Blob opcodes: EIP-4844 blob transactions are not supported
• PREVRANDAO entropy: Returns block-time-derived value, not true randomness — use VRF oracles here
• SELFDESTRUCT: Deprecated; refactor to “soft close” patterns

Step 2: Prepare Your Development Environment

Add Sei Network Configuration

Hardhat Configuration:

hardhat.config.ts

import { defineConfig, configVariable } from 'hardhat/config';
import hardhatToolboxMochaEthers from '@nomicfoundation/hardhat-toolbox-mocha-ethers';

export default defineConfig({
  networks: {
    seiMainnet: {
      type: 'http',
      chainId: 1329,
      url: 'https://evm-rpc.sei-apis.com',
      accounts: [configVariable('SEI_PRIVATE_KEY')]
    },
    seiTestnet: {
      type: 'http',
      chainId: 1328,
      url: 'https://evm-rpc-testnet.sei-apis.com',
      accounts: [configVariable('SEI_PRIVATE_KEY')]
    }
  },
  plugins: [hardhatToolboxMochaEthers]
});

Store your deployer key in Hardhat’s encrypted keystore with npx hardhat keystore set SEI_PRIVATE_KEY. Contract verification via Sourcify is enabled by default in Hardhat 3’s hardhat-verify (bundled with the toolbox).

Foundry Configuration:

foundry.toml

[profile.default]
src = "src"
out = "out"
libs = ["lib"]

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

# Verification uses Sourcify (no API key needed)
# Run: forge verify-contract --verifier sourcify --chain-id <CHAIN_ID> <ADDRESS> <PATH:CONTRACT>

See the Hardhat tutorial and Foundry guide for complete setup instructions.

Wallet Configuration

Pre-configure MetaMask or other wallets with Sei chain params:

const seiMainnet = {
  chainId: '0x531', // 1329
  chainName: 'Sei',
  nativeCurrency: { name: 'Sei', symbol: 'SEI', decimals: 18 },
  rpcUrls: ['https://evm-rpc.sei-apis.com'],
  blockExplorerUrls: ['https://seiscan.io']
};

await window.ethereum.request({
  method: 'wallet_addEthereumChain',
  params: [seiMainnet]
});

Step 3: Bootstrap Common Infrastructure

Sei already exposes canonical helper contracts—reference them instead of redeploying:

Component	Address	Notes
Permit2	0xB952578f3520EE8Ea45b7914994dcf4702cEe578	Shared allowance manager for DEX and wallet flows
Multicall3	0xcA11bde05977b3631167028862bE2a173976CA11	Enables batching and view aggregation
ImmutableCreate2Factory	0x0000000000FFe8B47B3e2130213B802212439497	Deterministic deployments with CREATE2
SingletonFactory	0xce0042B868300000d44A59004Da54A005ffdcf9f	EIP-2470 singleton factory

For third-party contracts (LayerZero, Safe, etc.), consult the full Ecosystem Contracts page.

Step 4: Port Contracts and Configuration

Parameterize Chain-Specific Constants

// Example: Chain-aware deadline calculation
function getDeadline(uint256 secondsFromNow) internal view returns (uint256) {
    if (block.chainid == 1329) { // Sei mainnet
        // ~2.5 blocks per second on Sei
        return block.timestamp + secondsFromNow;
    } else if (block.chainid == 1) { // Ethereum
        // ~1 block per 12 seconds on Ethereum
        return block.timestamp + secondsFromNow;
    }
    return block.timestamp + secondsFromNow;
}

Adjust Gas and Size Assumptions

• Keep gasLimit buffers modest but ensure calldata stays under 21 MB
• Sei’s 12.5M gas limit per block means large deployments may need batching

Refactor Deprecated Patterns

// Before: SELFDESTRUCT (deprecated)
function destroy() external onlyOwner {
    selfdestruct(payable(owner));
}

// After: Soft close pattern
bool public closed;

function close() external onlyOwner {
    closed = true;
    // Transfer remaining funds
    payable(owner).transfer(address(this).balance);
}

modifier notClosed() {
    require(!closed, "Contract is closed");
    _;
}

Step 5: Plan Bridging and Cross-Chain Connectivity

LayerZero V2

Sei’s LayerZero Endpoint ID is 30280. See the complete LayerZero integration guide.

layerzero.config.ts

import { EndpointId } from '@layerzerolabs/lz-definitions';

const seiContract = {
  eid: EndpointId.SEI_V2_MAINNET, // 30280
  contractName: 'MyOFT'
};

Other Bridge Options

• Circle CCTP: For USDC bridging (check availability)

Step 6: Handle Assets and Oracles

Oracle Integration

Sei supports multiple oracle solutions:

Provider	Use Case	Documentation
Pyth Network	High-frequency price feeds	Pyth Network
Chainlink	Industry-standard data feeds	Chainlink on Sei
RedStone	Modular oracle with push model	RedStone on Sei
API3	First-party oracle data	API3 on Sei

TWAP Adjustments: Because Sei blocks arrive ~30× faster than Ethereum, shorten your TWAP observation windows to maintain comparable time-weighted calculations.

Step 7: Launch Checklist

Testnet Deployment (atlantic-2)

• Deploy all contracts to testnet (chain ID: 1328)
• Run full integration test suite
• Verify contracts via Sourcify
• Test wallet connections and transaction flows
• Validate oracle integrations
• Test cross-chain messaging if applicable

Mainnet Deployment (pacific-1)

• Deploy contracts to mainnet (chain ID: 1329)
• Re-run smoke tests
• Verify all contracts on Sourcify
• Update frontend configurations
• Prepare user migration documentation

Fee Redistribution Warning: Fees on Sei are not burned. If your protocol redistributes “burn rebates” to users, redesign that logic so it does not expect a base-fee burn component.

Step 8: Operational Readiness

Contract Verification

Automate verification through CI using Sourcify:

# Foundry verification
forge verify-contract --watch \
  --verifier sourcify \
  --chain-id 1329 \
  <CONTRACT_ADDRESS> \
  <CONTRACT_NAME>

RPC and Indexer Health

• Primary RPC: https://evm-rpc.sei-apis.com
• Testnet RPC: https://evm-rpc-testnet.sei-apis.com
• For mission-critical paths, consider self-hosted nodes or premium RPC providers

Monitoring Gas Parameters

Periodically query fee data to keep dashboards aligned:

// Monitor current gas prices
const feeHistory = await provider.send('eth_feeHistory', ['0x5', 'latest', []]);
const gasPrice = await provider.getGasPrice();

Example: Uniswap V3-Style Deployment

Here’s how to mirror a Uniswap V3 experience on Sei:

1. Routers & Factories: Deploy your own or fork the existing DragonSwap stack:

   • Router: 0xdD489C75be1039ec7d843A6aC2Fd658350B067Cf
   • V3 Factory: 0x75FC67473A91335B5b8F8821277262a13B38c9b3
   • Position Manager: 0x8B3c541c30f9b29560f56B9E44b59718916B69EF

2. Permit and Multicall: Point your frontend SDK to the shared Permit2 and Multicall3 addresses above.

3. Liquidity Migration Script: Build a helper that:

   • Withdraws LP on source chain
   • Bridges underlying tokens to Sei
   • Mints new Sei LP positions
   • Include gas estimations tuned for Sei’s 12.5M block cap

4. Price Oracles: Reuse TWAP/Chainlink logic but shorten observation windows for Sei’s faster blocks.

5. Verification: Submit to Sourcify and the Ecosystem Contracts registry.

Helpful References

• Divergence from Ethereum – Opcode, gas, and state nuances
• EVM Networks – RPCs, explorers, and MetaMask payloads
• Precompiles – Interoperability patterns
• Ecosystem Contracts – Canonical addresses
• LayerZero Integration – Cross-chain messaging
• Contract Verification – Contract verification guide