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Introduction to Native Supernet Bridging

This document provides an overview of the native cross-chain bridge in Supernets.

The bridge should not yet be used in production environments
Arbitrary message transfers

The bridging mechanism in Supernets currently supports the ERC-20, ERC-721, and ERC-1155 token standards for asset transfer. However, customization may be required for transferring arbitrary messages, including other asset standards, as Supernets are still in active development mode.


Supernets provide a built-in bridging mechanism that enables cross-chain communication. The bridging mechanism is a technical infrastructure that facilitates the transfer of of arbitrary messages between any EVM-compatible PoS blockchain (rootchain), and a Supernet.

It relies on mapping between the token contracts on the rootchain and the target chain, which is crucial for tracking assets and ensuring the correct amount of tokens are minted and burned during the transfer process.

During the transfer process, assets are locked in a contract on the rootchain, and an equivalent amount of tokens are minted on the target chain. When assets are withdrawn from the target chain, the corresponding tokens are burned, and the assets are unlocked on the rootchain. Smart contracts on both the rootchain and the target chain are used to facilitate these processes, ensuring that the asset transfer is secure and transparent.

Enabled by Default

The cross-chain bridge in Supernets is an integral part of the consensus client and is enabled by default. It cannot be disabled, as it is required for the functioning of the network. Being native to the Supernets, the bridge is built into the protocol and does not require any external third-party solutions or plug-ins.

If you choose to use another cross-chain bridging mechanism, you will need to customize it yourself, and there are no guarantees of compatibility with associated contracts and infrastructure.


The following diagram above provides a visual representation of how messages can be passed between different EVM blockchain layers, allowing for seamless message tranfers and coordination between various components of a Super network.

How does message passing work?

StateSync: real-time synchronization

Message passing between a rootchain and a Supernet is achieved through continuous state synchronization, known as StateSync. This process involves transferring state data between system calls.

Check out the StateSync document to learn more.

Checkpoints: Ensuring liveliness and reference points

When passing messages from a Supernet to a rootchain, the validator set commits checkpoints, which are snapshots of the Supernet state containing only the root of the Exit events, excluding all transactions. Checkpoints serve as reference points for clients, and validators periodically checkpoint all transactions occurring on the Supernet to the rootchain. Checkpoints also ensure liveliness and are submitted to the associated rootchain asset contract.

Check out the Checkpoint document to learn more.

Bridge States: tracking event progress

The bridge can exist in one of three states:

  • Pending: Events are waiting to be bundled and sent over.
  • Committed: Event data has been relayed to the associated chain.
  • Executed: The event has been committed, and the state executed, resulting in a state change.

Assets: supporting a range of standards

The bridge is compatible with various token standards, including ERC-20, ERC-721, and ERC-1155, enabling a wide range of assets to be transferred between chains.