# Sei > Sei is the fastest EVM blockchain, purpose-built for high-frequency applications with 400ms finality, parallelized execution, and sub-cent transaction fees. Fully EVM-compatible — deploy Solidity contracts and use existing Ethereum tooling with no modifications. ## Overview Sei is a Layer 1 blockchain optimized for speed and throughput. It delivers 100 MGas/s and ~12,500 TPS using Twin Turbo consensus and parallel EVM execution. The upcoming Sei Giga upgrade targets 200,000 TPS and 5 gigagas/s throughput via Autobahn multi-proposer BFT consensus. SEI is the native token used for gas fees, staking, and governance. USDC is natively available on Sei for payments and DeFi. ### Key Performance Characteristics - 400ms block finality (vs 12+ seconds on Ethereum) - 100 MGas/s throughput (current), 5 gigagas/s target (Sei Giga) - ~12,500 TPS (current), 200,000 TPS target (Sei Giga) - Sub-cent transaction fees - Full EVM compatibility — standard Solidity, Hardhat, Foundry, wagmi, ethers.js all work unmodified ### Network Configuration Mainnet (pacific-1): Chain ID 1329, RPC https://evm-rpc.sei-apis.com Testnet (atlantic-2): Chain ID 1328, RPC https://evm-rpc-testnet.sei-apis.com ### Architecture Sei's performance comes from three core innovations: Twin Turbo Consensus: Optimistic block processing that begins executing transactions before consensus is finalized, dramatically reducing latency. Validators exchange block data via an intelligent propagation protocol that minimizes redundant data transfer. Parallel EVM Execution: Transactions that touch different state are executed concurrently across multiple CPU cores. Sei uses an optimistic concurrency model — transactions execute in parallel, and conflicts are detected and re-executed only when they occur. SeiDB: A storage layer optimized for high-throughput blockchain workloads, replacing the standard Cosmos IAVL tree with a more performant architecture designed for concurrent reads and writes. ### Sei Giga Sei Giga is the next major upgrade introducing: Autobahn Consensus: A multi-proposer BFT protocol where multiple validators propose blocks simultaneously, eliminating the single-proposer bottleneck. This enables linear scaling of throughput with validator count. Custom EVM Client: A purpose-built EVM execution engine optimized for Sei's parallel architecture, replacing the standard go-ethereum client. Target: 5 gigagas/s (5 billion gas units per second), 200K+ TPS, sub-400ms finality. ### USDC on Sei Native USDC (6 decimals): - Mainnet: 0xe15fC38F6D8c56aF07bbCBe3BAf5708A2Bf42392 - Testnet: 0x4fCF1784B31630811181f670Aea7A7bEF803eaED ## AI & Agent Integration Sei is designed as the payment and execution layer for the AI agent economy. Three core primitives: ### MCP Server (@sei-js/mcp-server) The Sei Model Context Protocol server enables AI assistants (Claude, ChatGPT, Cursor, Windsurf) to interact with Sei via natural language. Install with `npx -y @sei-js/mcp-server`. 29+ tools organized into read-only and wallet-enabled categories: Read-only tools: get_chain_info, get_supported_networks, get_block_by_number, get_latest_block, get_balance, get_erc20_balance, get_token_balance, get_transaction, get_transaction_receipt, estimate_gas, get_token_info, is_contract, get_nft_info, check_nft_ownership, get_erc1155_token_uri, get_nft_balance, get_erc1155_balance. Wallet tools (require PRIVATE_KEY): transfer_sei, transfer_erc20, approve_token_spending, transfer_nft, transfer_erc1155, transfer_token, read_contract, write_contract, deploy_contract, get_address_from_private_key. Documentation search: search_docs (main Sei docs), search_sei_js_docs (@sei-js library docs). Supports all Sei networks. Configuration requires adding to your AI assistant's MCP config with the command `npx -y @sei-js/mcp-server` and optional PRIVATE_KEY and NETWORK environment variables. Source: https://github.com/sei-protocol/sei-js/tree/main/packages/mcp-server ### Cambrian Agent Kit SDK for building autonomous AI agents on Sei with DeFi protocol integrations. Supports token operations (SEI, ERC-20, ERC-721), DeFi protocols (Takara lending, Silo lending, Citrex perpetuals, Symphony aggregation), swap functionality via Symphony, and liquidity management via DragonSwap. Extensible via the Cambrian Agents Plugin Guide. ### x402 Protocol HTTP 402-based micropayment standard enabling machine-to-machine payments. An AI agent makes an HTTP request, receives a 402 Payment Required response with payment instructions, signs and sends payment on Sei (USDC), and the server confirms payment (~400ms on Sei) and returns the content. Use cases: per-inference pricing for LLM APIs, pay-per-view content, real-time data feeds, IoT data monetization. Sei's 400ms finality makes x402 viable for real-time agent workflows where Ethereum's 12+ second finality would be unusable. The sei-js library provides packages for both server-side (payment verification) and client-side (payment signing) x402 integration. ## Development Sei is fully EVM-compatible. Any Ethereum toolchain works without modification. ### Smart Contracts Hardhat: Standard Hardhat setup with Sei network configuration. Use OpenZeppelin for ERC20, ERC721, access control. Deploy to testnet first (atlantic-2), verify, then deploy to mainnet. Foundry: Standard Foundry project structure (src/, test/, script/). Full forge test and forge script support. Key difference from Ethereum: Sei's parallel execution rewards contracts that use user-scoped state (mapping per address) over shared global state. Contracts with independent state per user execute in parallel automatically. ### Frontend wagmi + viem: Recommended stack. Configure with Sei chain definitions from viem/chains. Standard useReadContract, useWriteContract, useConnect hooks work as-is. ethers.js: Full support via JsonRpcProvider with Sei RPC URLs. RainbowKit: Drop-in wallet connection UI with Sei network support. ### Oracles Sei's native oracle module has been retired via governance proposal 110 and removed from the codebase as of version 6.5. On-chain price feeds are now provided by third-party oracle providers: Chainlink, API3, and Pyth. Developers requiring price data should integrate directly with these providers rather than the former native oracle precompile. ### Precompiles Sei exposes native chain functionality to EVM contracts via precompiled contracts at fixed addresses. This includes staking/delegation, governance voting, IBC transfers, and pointer contracts that bridge between EVM and Cosmos token standards. ## Documentation - [Sei Docs](https://docs.sei.io): Technical documentation for building on Sei - [Sei-JS Documentation](https://sei-js.docs.sei.io): JavaScript/TypeScript SDK documentation - [Sei Giga Overview](https://docs.sei.io/learn/sei-giga): Architecture and roadmap for Sei Giga - [Sei Giga Developer Guide](https://docs.sei.io/learn/sei-giga-developers): Developer guide for Sei Giga ## Key Resources - [GitHub](https://github.com/sei-protocol): Open source repositories including sei-chain, sei-js, and MCP server - [Ecosystem](https://www.sei.io/ecosystem): Directory of projects building on Sei - [Blog](https://blog.sei.io): Latest news, announcements, and technical deep dives - [Institutions](https://www.sei.io/institutions): Enterprise blockchain solutions and institutional partnerships - [Media Hub](https://www.sei.io/media): Press kit, brand assets, and community resources ## Optional - [Staking Guide](https://docs.sei.io/learn/general-staking): Proof-of-stake delegation with 21-day unbonding period - [Token Standards](https://docs.sei.io/learn/dev-token-standards): ERC20, ERC721, CW20, CW721, IBC tokens, and pointer contracts - [Wallets](https://docs.sei.io/learn/wallets): MetaMask, Compass, Fin, Keplr, hardware wallets, passkey wallets - [Node Operations](https://docs.sei.io/node): Running full nodes, archive nodes, and validator nodes - [Oracle Providers](https://docs.sei.io/learn/oracles): Third-party oracle providers (Chainlink, API3, Pyth) — native oracle retired via proposal 110 - [Precompiles](https://docs.sei.io/evm/precompiles/example-usage): Native Sei functionality exposed to EVM - [Ecosystem Contracts](https://docs.sei.io/evm/ecosystem-contracts): Registry of verified smart contract addresses - [Interoperability](https://docs.sei.io/learn/dev-interoperability): Cross-chain capabilities via IBC and precompiles