Token Standards

Use ERC20 / ERC721 / ERC1155 for new tokens. Per Proposal 115 , CosmWasm code uploads and contract instantiations are disabled on Sei, so no new CW20 / CW721 / CW1155 tokens can be deployed. The CW standards described below are documented for users and developers interacting with already-deployed legacy contracts.

In this section, we delve into the various token standards supported on Sei. Understanding these standards is crucial for developers as they form the foundation of many decentralized applications.

Sei offers support for the following token types:

Sei Token
Smart Contract Tokens

Sei Token

The Sei token is the native token of the Sei blockchain, serving multiple roles within the ecosystem.

Fee Token: Used to pay transaction fees on the Sei network.
Governance Token: Used to participate in governance decisions affecting the network.

EVM

1sei = 10**18 wei = 1000000000000000000 wei

1sei = 10**9 gwei = 1000000000 gwei (giga-wei)

Cosmos

1sei = 10**18 asei = 1000000000000000000 asei (atto-sei)

1sei = 10**9 nsei = 1000000000 nsei (nano-sei)

1sei = 10**6 usei = 1000000 usei (micro-sei)

1 gwei = 1 nsei

Fungible Tokens

Fungible tokens are digital assets that are interchangeable with one another and are not unique. Sei supports both ERC20 and CW20 fungible token standards.

Smart Contract Tokens

ERC20 (recommended): The ERC20 standard defines a common set of rules for fungible tokens on EVM-based blockchains. These tokens can be transferred, approved, and queried using standard functions. Use ERC20 for any new fungible token on Sei.
CW20 (legacy only): The Cosmos-side fungible token standard. Per Prop 115 , no new CW20 contracts can be deployed. Existing CW20 tokens continue to function and can still have pointer contracts created for them.
Interoperability and Pointer Contracts: Pointer contracts expose existing CW20 tokens as ERC20 on the EVM. A registry tracks pointer contracts and facilitates discovery.

Interoperability: Existing CW20 tokens can have ERC20 pointer contracts deployed for them. New tokens should be deployed as ERC20 directly.

For more detailed guidance, refer to the Pointer Contracts Documentation.

NFTs

Non-fungible tokens (NFTs) represent unique digital assets. Sei supports ERC721 and ERC1155 (and their royalty-aware counterparts via ERC2981) as the standards for new NFT collections, along with legacy CW721 / CW1155 contracts.

ERC721 / ERC1155 (recommended): EVM standards for non-fungible and semi-fungible tokens. Use these for any new NFT collection on Sei.
ERC2981: Defines a royalty mechanism for NFTs, ensuring creators receive a percentage of sales.
CW721 / CW1155 (legacy only): Per Prop 115 , no new CW721 / CW1155 contracts can be deployed. Existing collections continue to function and can be surfaced on the EVM via pointer contracts.
Interoperability: Similar to fungible tokens, legacy CW NFT collections can interact with the EVM using pointer contracts.

Wrapped Sei (wSei)

Some dApps may require Sei tokens to be wrapped in order to interact with them (similar to Wrapped ETH on Ethereum). The Wrapped Sei Token WSEI is deployed under the contract address 0xE30feDd158A2e3b13e9badaeABaFc5516e95e8C7.