Sei utilizes multiple chains for various stages of the development lifecycle. This multi-chain approach allows developers to build, deploy, manage, and iterate confidently, ensuring thorough testing and feedback before updates go live on the mainnet.

All chain updates are first deployed to the devnet to ensure stability. They are then moved to the testnet for further testing and validation. Finally, the updates are released to the mainnet. This process allows developers to test their applications thoroughly and raise any concerns regarding the upgrades before they go live on the mainnet.


The pacific-1 chain is the mainnet of the Sei blockchain. It is the live, production environment where actual transactions and smart contract deployments occur. This chain is used for all real-world applications and activities.

  • Purpose: Production
  • Chain ID: pacific-1
  • EVM Chain ID: 1329 or 0x531


The atlantic-2 chain is the testnet of the Sei blockchain. It is used for testing and development purposes. Developers can deploy and test their dApps and smart contracts in a controlled environment that simulates the mainnet conditions. This chain is crucial for ensuring that applications work as expected before going live.

  • Purpose: Staging
  • Chain ID: atlantic-2
  • EVM Chain ID: 1328 or 0x530


The arctic-1 chain is the devnet of the Sei blockchain. It serves as a development network for early-stage testing and experimentation. This chain is typically used by developers to test new features, perform integration testing, and develop prototypes in an isolated environment.

  • Purpose: Testing
  • Chain ID: arctic-1
  • EVM Chain ID: 713715 or 0xAE3F3

Local Chains

Developers can also run local chains on their machines for testing and development purposes. Local chains are isolated environments that mimic the behavior of the mainnet, testnet, or devnet chains. They are useful for testing new features, debugging issues, and experimenting with smart contracts with full control over all tokens and governance decisions.

  • Purpose: Development
  • Chain ID: Set by user (default: sei-chain)

Please read the Nodes Introduction section for more information on how to set up and run a local chain.

Chain Registry

The Sei Chain Registry (opens in a new tab) contains additional information about each chain.