Gateway is an interface that serves as a unified entry point for interactions between contracts on connected chains and universal apps on ZetaChain.
Gateway on Connected Chains
The gateway on connected chains (like Ethereum, Solana and Bitcoin) facilitates incoming transactions: contract calls and token transfers from connected chains to universal apps on ZetaChain.
The implementation of the gateway depends on the connected chain:
- EVM chains: a gateway smart contract
- Solana: a gateway program
- Bitcoin: a TSS MPC gateway address managed by a network of observer-signer validators
Each chain has only one gateway. The same gateway is used to interact with all universal apps.
Gateway supports the following features:
- depositing native gas tokens to a universal app or an account on ZetaChain
- depositing supported ERC-20 tokens (including ZETA tokens) to a universal app or an account on ZetaChain
- depositing native gas tokens and making a contract call (with arbitrary data passing) to a universal app
- depositing supported ERC-20 tokens and making a contract call (with arbitrary data passing) to a universal app
- making a contract call (with arbitrary data passing) to a universal app
These features may vary depending on each specific connected chain. For example, deposits from Bitcoin can only be made in native gas token (BTC). And deposits from Solana can be made in SOL and (soon) SPL tokens.
Currently, only one asset can be deposited at a time to a universal app. Support for multi-asset deposits will be added in the future updates to the protocol.
Gateway on ZetaChain
Gateway on ZetaChain facilitates outgoing transactions: calls and token withdrawals from universal apps to contracts on connected chains.
Gateway supports the following features:
- withdrawing ZRC-20 tokens as native gas or ERC-20 tokens to connected chains
- withdrawing ZETA tokens to a connected chain
- withdrawing tokens to and making a contract call on a connected chain
- making a contract call on a connected chain
Currently, only one asset can be withdrawn at a time from a universal app. Support for multi-asset withdrawals will be added in the future updates to the protocol.