Contest: PolkaDot↔FreeTON Bridge Implementation: Stage 2

Contest dates

Warm-up period: Tuesday, February 2, 2021 12:00 AM Coordinated Universal TimeTuesday, February 2, 2021 11:59 PM Coordinated Universal Time

Submission period: Wednesday, February 3, 2021 12:00 AM Coordinated Universal TimeMonday, March 8, 2021 11:59 PM Coordinated Universal Time

Short description

Implement Stage 2 of the winning architecture of the PolkaDot↔FreeTON Bridge Design and Architecture contest with the milestone “Transferring tokens between FreeTON ↔ Polkadot chains”.


Chained contest


  1. Send a simple message from FreeTON to Substrate-based blockchain
  2. Transferring tokens between FreeTON ↔ Polkadot chains
  3. Distribution of relayer responsibilities Begin the economy model implementation
  4. Staking, Rewards and slashing; Run Canary Network


A significant challenge of blockchains to date is their lack of interoperability. Once a developer builds their decentralized application on any particular platform, they’re generally locked into that platform with no opportunity to leverage any of the benefits of other blockchains.

We believe that the future of blockchain technology is to allow all major networks to interact with one another and to be able to share value and information.

Both ecosystems, Polkadot and FreeTON share these views and we want to add the possibility to interoperability through the cross-chain message passing (XCMP) protocol, thus we open up many opportunities for awesome projects in the market of DeFi.

Web3 Foundation is delivering a decentralized and fair internet where users control their own data, identity, and destiny. Building a bridge with flagship product Polkadot will allow FreeTON to reach a whole new level.

General requirements

  • Cross-chain message-passing protocol with censorship resistance
  • The protocol must have the ability to add methods of decentralized governance (proposals, voting, rewards, slashes)
  • The possibility of trustless and non-custodial transfer of value between networks
  • Open sources of documentation published at GitHub/GitLab or another open repository

Fair play

As per Procedural remarks on contests.

Evaluation criteria and winning conditions

Hard criteria

  • Codebase support. Optimize a TON smart-contracts codebase according to new version compiler features
  • Implement VRF (verifiable random function) in relay node source code
  • Depositing and issuing TIP-3 token in FreeTON network.
  • Depositing and issuing token in substrate-based network
  • DevOps tools. Preparing containers, configs, and scripts for bridge deploying
  • Documentation. Detailed structured documentation for development tools and step-by-step examples to prove deliverables of this stage

Soft criteria

  • Detailed and easily understandable charts explaining the architecture and business processes
  • Brevity
  • Mostly everyday English to facilitate understanding
  • Readiness to participate in the implementation of the solution in the next stage


  • Relay node source code:
    • VRF (verifiable random function)
  • FreeTON smart-contracts and Substrate:
    • Optimized TON smart-contracts from the first stage
    • Handlers of TIP-3 token depositing/issuing on FreeTON side
    • Handlers of token depositing/issuing on Substrate side
  • DevOps tools:
    • Add CI/CD scripts to existing deploy tools repository
  • Link to documentation at Github/Gitlab or another open repository, with the obligatory backlink to your submission in the repository’s README

Winning conditions

  • Only the winners who have obtained a prize place in the previous stage of the contest are allowed to participate
  • To apply for the next stage of the competition, you need:
    • take a prize in one of the first three places
    • score at least 5 points in the voting from the jury


1 place ……………………….140 000 TON

2 place ……………………….90 000 TON

3 place ……………………….50 000 TON

Procedural remarks to jurors

As per Procedural remarks on contests.

Jury rewards

As per Procedural remarks on contests.

Governance rewards

As per Procedural remarks on contests.

Procedural reminders to all contestants

As per Procedural remarks on contests.


Stage 2 of the PolkaDot↔FreeTON Bridge Design and Architecture Implementation contest


  • Public address: 0:70a07fa3d93d0058ec85ca2a16c88cb0abc680688d850c00d3b2828d3c5070ab


Our team is grateful for choosing our architecture as the winner of the “PolkaDot↔FreeTON Bridge Design and Architecture” contest but we do not want to stop there. We have proposed a roadmap for the implementation of our architecture and this contest is the first stage of our roadmap.

We are proud to present to you our solution for the first stage is DOTON Bridge .

DOTON Bridge is an implementation of message passing protocol based on ChainBridge and extended to make it possible to work with TON chain.

In this stage, we added support for fungible tokens transfer between freeTON and Substrate-based (Polkadot parachains) networks.

If you looking for a simple way to try bridge in action, please visit the page - Running Locally


Source code


Docker images