Intergalactic PioNEARing with Axelar

✨ Inspiration

This cutting-edge technology is enabled by the release of Aurora Engine 2.9.0 on April 21st 2023, which allows Near XCC cross-contract calls from within Aurora EVM. We combine this capability with the power of Axelar GMP to allow users in any EVM or Cosmos chain to make a cross-chain call to NEAR smart contracts.

👀 What it does

To showcase this technique, we developed an intergalactic themed passport dApp which allows users to gain a stamp in their passport for each chain they use along the way. Once the space traveler makes it all the way to NEAR, a celebratory social media post is created on Near Social, a smart contract on the NEAR blockchain. Overall, a smart contract on Avalanche (or any other Axelar-supported chain) makes a successful Interchain Message and Cross-Chain Call to a smart contract in the NEAR blockchain.

🌌 Example Interchain Transaction to NEAR

1. Using Axelar Explorer, you can see how we sent the transaction using General Message Passing: Successful Transaction on Axelar Explorer.
2. That transaction continues on through to NEAR, which is best viewed on NEAR explorer: Successful Transaction on NEAR Explorer.
3. As a result, the social media post requested in the body of the call on Avalanche is successfully posted to a NEAR smart contract, and the results can be viewed on the Near Social website: Successful Near Social Passport Post Creation.

💻 How we built it

We created 2 EVM smart contracts in Solidity, HomePlanet.sol and NearlyIntergalactic.sol. These contracts use Axelar General Message Passing to make a cross-chain call from the Home Planet (any chain supported by Axelar; we used Avalanche) to the Nearly Intergalactic contract in Aurora. This contract uses a version of Aurora SDK that we customized for this purpose (seen here) to make an XCC cross-contract call at the NEAR level.

For the front end, we used React-Typescript with ethers.js and MetaMask integration to create an intergalactic traveler passport dApp, showcasing the interchain functionality by awarding the user with a stamp for each chain visited along the way, and finally posting the completed passport to Near Social by successfully making a NEAR call all the way from our Home Planet of Avalanche.

🚀 Accomplishments that we're proud of

• We connected two blockchains that were never before possible to connect in this way!
• We demonstrated how to expand the capabilities of Axelar to include support for Interchain calls to NEAR.
• We created a dApp frontend which we enjoy using and which integrates multiple chains.

Experience learning and using Axelar

✅ The interchain capability allowed us to really bring this idea to life
✅ Tutorials and docs were really well made so really helped hitting the ground running
✅ AxelarScan made it really easy to visualize the GMP transactions as they went through

➖ When running on testnet, the time seemed to vary from 1 minute 30 to 4 minutes 30 for the same transaction
➖ When AxelarScan errors, it isn't too verbose on the cause of error

📈 What's next for Intergalactic PioNEARing with Axelar

We are excited to have been successful in connecting NEAR with Axelar. Some of the next steps we look forward to include:

• Interchain Tokens (ERC-20 to NEP-141)
• Interchain NFTs (ERC-721 to NEP-171)
• Arbitrary Near Cross-Contract Calls
• 2-way GMP Equivalent

📄 Links

Powerpoint Presentation

Thank you! We hope you enjoy our multi-chain, multi technology project which opens more doors in the web3 ecosystem.

🧑‍💻 Instructions for testing locally

1. Deploy NearlyIntergalactic on Aurora with the following values:

   • nearSocialAccountId = v1.social08.testnet
   • wNEAR = 0x4861825E75ab14553E5aF711EbbE6873d369d146
   • gateway = 0x304acf330bbE08d1e512eefaa92F6a57871fD895
   • gasReceiver = 0xA2C84547Db9732B27D45c06218DDAEFcc71e452D

2. Deploy HomePlanet on any Axelar-supported chain, such as Avalanche shown here:

   • gateway = 0xC249632c2D40b9001FE907806902f63038B737Ab
   • gasReceiver = 0xbE406F0189A0B4cf3A05C286473D23791Dd44Cc6

3. Ensure that NearlyIntergalactic has the needed wNEAR.

4. Use the dApp web UI to begin your journey, which will call HomePlanet.travelToNear():

   • destinationChain = aurora
   • destinationAddress = <NearlyIntergalactic address>
   • attachedNear = <Quantity of wNEAR to attach, ex. 3000000000000000000000000>
   • data = <Near Social DB, as Bytes Encoded JSON>
   • {msg.value} = 100000000000000000 wei