HomeBlockchainDevelopment Status of Rainbow Cross-Chain Bridge for The Open Network

Development Status of Rainbow Cross-Chain Bridge for The Open Network

The Open Network (TON) currently provides multiple excellent cross-chain solutions: a bridge for Toncoin between the TON network and Ethereum or BNB Smart Chain, as well as a token bridge that enables the transfer of Ethereum tokens (such as USDT or USDC) to the TON network and vice versa.  

Smart contracts and decentralized oracles manage the transfers between the networks. This commonly accepted solution ensures stability and security. However, we strive to take it to the next level so you can conduct all operations on smart contracts without intermediaries.

Such solutions are called “trustless” or “rainbow,” and achieving something similar is a technically complex and ambitious task.

For over six months, together with the RSquad team of blockchain experts, we have been working on such a solution for the TON blockchain, and we are pleased to announce the intermediate results.

TON → EVM Direction

We have developed a technology for transferring Toncoin from the TON network to any EVM network that operates entirely on smart contracts.

To make this possible, we have done significant work and implemented, in the Solidity language, the entire logic for verifying and confirming blocks and transactions of the TON blockchain.

The mechanism for expanding functionality is provided – in addition to Toncoin transfers, developers can easily add support for token transfers, NFTs, and other cross-network operations.

You can already review the open-source code of these smart contracts and a demo application that allows you to transfer Toncoin from the TON testnet to the Ethereum testnet.

The bridge demo is available here.

Source code:

To access relayer docs, click here.

Ethereum → TON Direction

Next, we are working on supporting transfers from the Ethereum network to the TON network. In this case, it is necessary to validate the transactions and blocks of the Ethereum network using TVM smart contracts.

We conducted in-depth research on this topic, which you can review at docs.ton.org

With the latest update to the TON Virtual Machine (TVM) and the addition of advanced cryptography, there are no more obstacles, and along with the RSquad team, we are proceeding with this part of the work.


The Open Network project devotes much time to creating solutions and technologies that connect different networks while aiming at maximum decentralization and security.

We hope these intermediate results will interest developers, and we plan to complete the work’s second part by the end of this year.

Anatoly Makosov
Anatoly Makosov
Core developer at TON Foundation