Inspiration

World Wide Link is a Cross-Chain DeFi Hub powered by CCIP, providing access to various financial tools to facilitate any transaction, including integration with protocols of different blockchains, all in one place.

** WWL Provides: 1) Multipurpose Escrow 2) Lending and Borrowing 3) SOS Alerts based automatic fund transfer 4) Cross-Chain liquid staking 5) On/Off Ramp 6) Token Transfer

What it does

⚖️ Multipurpose Escrow: Multipurpose Cross-Chain escrow agreement ensures ethical behavior in decentralized transactions between two parties. In WWL, both parties stake tokens, offering dispute resolution through a DAO arbitrator.

🔄 Lending and Borrowing: CCIP-powered Cross-Chain Lending and Borrowing: Seamlessly support Ethereum, Polygon, and Avalanche through the WWL, eliminating the need for bridging or native gas tokens.

🚨SOS Alerts-based automatic fund transfer: Millions locked on the chain may be inaccessible in emergencies. With WWL SOS Alerts, set triggers: if inactive, Trigger 1 sends an email via Chainlink Keeper; if still inactive, Trigger 2 alerts loved ones and transfers funds.

💼 Liquid Staking: Cross-chain liquid staking aggregator that enables users to provide liquidity across different protocols on various blockchains, all on one platform.

💸 On/Off-Ramp Integration: WWL offers integration with the Transak SDK to simplify the process for users to on and off-ramp crypto to WWL.

🔄 Token Transfer: Users can seamlessly transfer tokens across different blockchains within the Dapp, eliminating the need for bridging, managing native tokens for gas fees, or handling multiple wallets.

🎉 Airdrop: Created a subgraph to retrieve user transactions from cross-chain lending/borrowing contracts and rewarded them with an airdrop of WWL tokens.

Check Live

https://worldwidelink.xyz

Chainlink, Avalanche, Polygon, and The Graph integration details:

Chainlink: We have used different Chainlink products including 1) CCIP 2) Chain Automation 3) Data Feeds 4) VRF 5) Proof of Reserves 6) Functions 7) Chainlink Node-External adapter. Below are the details of the integration:

Avalanche | Polygon: We built a Cross-Chain Defi hub that enables defi transactions between Avalanche, Polygon, and Ethereum for various use cases such as Escrow, Liquid Staking, Lend/Borrow

Avalanche Contracts:

1. Cross-Chain Escrow https://testnet.snowtrace.io/address/0x52C1da029735C798Ef0B94ba85C2C30ef378D5f4 Using CCIP we Implemented, Cross-Chain Escrow, Lending / Borrowing, Liquid Staking and asset transfer among Ethereum/Avalanche/ Polygon.

2. Proof of Reserve Proof of Reserve Monitoring BTC.b's PoR triggers alerts and maintains on-chain reputation by tracking Avalanche's collateral ratio. Users receive email alerts for low ratios, and frequent imbalances reduce the pool's reputation. https://testnet.snowtrace.io/address/0xe28F1cfe684e907fdb9cC815b50a5dBF5350d007

3. Cross-Chain Lending/Borrowing (Sender): https://testnet.snowtrace.io/address/0xD9902C09d1104f068772623F91dC9555545192dd

(Receiver Protocol): https://testnet.snowtrace.io/address/0x2123e642A12d6Ce9B292B9F166971DFa97319b2D

(Price Feed): https://testnet.snowtrace.io/address/0x040Dd256A46e8fFdD5Ffeb6F95FE9b5c02828D88

(Data Feeds) To fetch real-time Ethereum and Matic prices, enabling users to peg 1 CCIP to 1 Eth on Ethereum and 1 CCIP to 1 Matic on Polygon for lending/borrowing.

4. Cross-Chain Liquid staking (Staking) https://testnet.snowtrace.io/address/0x670936746cF7ab5Eec356e81E9a62556140CDfB5 (Unstake) https://testnet.snowtrace.io/address/0xC3ED8D3Ddef66cea43e9D3d74981869aE2C8718F

5. WWL Token Airdrop https://testnet.snowtrace.io/address/0xA7a9cB2a4b88a5C85431808F6a3292b35d3dF337 To airdrop WWL tokens to an early user who interacted with any of the contracts from Escrow, Lend/Borrow, and Liquid Staking

The Graph: Created a subgraph to retrieve user transactions from cross-chain lending/borrowing contracts and rewarded them with an airdrop of WWL tokens.

Sub Graph - The Graph : https://api.studio.thegraph.com/query/44401/wwl/0.0.1

World Wide Link Product demo :

Integration details for Chainlink, Avalanche | Polygon and The Graph.

In WorldWideLink (WWL) we have used different Chainlink products including 1) CCIP 2) Chain Automation 3) Data Feeds 4) VRF 5) Proof of Reserves 6) Functions 7) Chainlink Node-External adapter. Below are the details of the integration:

Service Name	Blockchain | Contract | Code implementation
CCIP Using CCIP we Implemented, Cross-Chain Escrow, Lending / Borrowing, Liquid Staking and asset transfer among Ethereum/Avalanche/ Polygon.	Avalanche - (Escrow) https://testnet.snowtrace.io/address/0x52C1da029735C798Ef0B94ba85C2C30ef378D5f4 Code: https://github.com/jaydippatel83/worldwidelink/blob/master/smart_contracts/escrow/Escrow.sol Line No: 1 to 726 (Lending/Borrowing) Sender: https://testnet.snowtrace.io/address/0xD9902C09d1104f068772623F91dC9555545192dd Code: https://github.com/jaydippatel83/worldwidelink/blob/master/smart_contracts/lending-borrowing/Sender.sol Line No: 1 - 260 Receiver Protocol: https://testnet.snowtrace.io/address/0x2123e642A12d6Ce9B292B9F166971DFa97319b2D Code: https://github.com/jaydippatel83/worldwidelink/blob/master/smart_contracts/lending-borrowing/WorldWideLinkProtocol.sol Line No: 1 - 474 (Liquid staking) Staking: https://testnet.snowtrace.io/address/0x670936746cF7ab5Eec356e81E9a62556140CDfB5 Code: https://github.com/jaydippatel83/worldwidelink/blob/master/smart_contracts/Liquid-Stake/LiquidStaking.sol Line No: 1 - 185 Unstake: https://testnet.snowtrace.io/address/0xC3ED8D3Ddef66cea43e9D3d74981869aE2C8718F Code: https://github.com/jaydippatel83/worldwidelink/blob/master/smart_contracts/Liquid-Stake/UnStake.sol Line No: 1 - 204 Sepolia - (Escrow) https://sepolia.etherscan.io/address/0xbb5fd7e998526c64F8CBa3C3Cc526E510Dd6BdC4 (Lending/Borrowing) Sender: https://sepolia.etherscan.io/address/0x53cc33bCb8f54BD041210Be871b7b3FAF3884ac2 Receiver Protocol: https://sepolia.etherscan.io/address/0x67179faFCB5Fbf8F106DaFFA3fb70e1369c1Fc3f (Liquid staking) (Asset Transfer) https://sepolia.etherscan.io/address/0x253b3b4807076Cf51c3Cda5Ebd5DA290DdD89f13 Code: https://github.com/jaydippatel83/worldwidelink/blob/master/smart_contracts/transfer/Transfer.sol Mumbai - (Escrow) https://mumbai.polygonscan.com/address/0x9519db24fE1FfB1Be531D4c66eA01Eb61B51F82a (Lending/Borrowing) Sender: https://mumbai.polygonscan.com/address/0x3Db45de715929b76E0570d01815F20eEe576B9E7 Receiver Protocol: https://mumbai.polygonscan.com/address/0x9c29a12d441757AcF45aa106A3905E85C008dFA2 (Liquid staking) (Asset Transfer) https://mumbai.polygonscan.com/address/0xFf72875645e3a6DFAc819a14a98c93b01D3f449B
Automation logic-based automation in 1) Automated SOS email and 2) SOS-triggered automated crypto asset transfers. Note: Detailed information for implementation is covered in the next section.	Mumbai (Sos Alert) https://mumbai.polygonscan.com/address/0xdC1A55051B529e23B67f621332a0D0953771c3Fc Code: https://github.com/jaydippatel83/worldwidelink/blob/master/smart_contracts/sos-alert-contracts/SosTokenTransfer.sol Line No: 1 to 131
Data Feeds To fetch real-time Ethereum and Matic prices, enabling users to peg 1 CCIP to 1 Eth on Ethereum and 1 CCIP to 1 Matic on Polygon for lending/borrowing.	Avalanche https://testnet.snowtrace.io/address/0x040Dd256A46e8fFdD5Ffeb6F95FE9b5c02828D88 Sepolia https://sepolia.etherscan.io/address/0xd1B48c231eE234C89BC02E6E7C80F75115DFD04D Mumbai https://mumbai.polygonscan.com/address/0x6e4563C4F0FE668196C8878Cb89bdEF15b66e9B2 Code: https://github.com/jaydippatel83/worldwidelink/blob/master/smart_contracts/price_feed/Price_feed.sol Line No: 1 - 57 Code: https://github.com/jaydippatel83/worldwidelink/blob/master/smart_contracts/lending-borrowing/WorldWideLinkProtocol.sol Line No: 209 - 230
VRF (Airdrop) To airdrop WWL tokens to an early user who interacted with any of the contracts from Escrow, Lend/Borrow, and Liquid Staking	Avalanche https://testnet.snowtrace.io/address/0xA7a9cB2a4b88a5C85431808F6a3292b35d3dF337 Sepolia https://sepolia.etherscan.io/address/0x2998C45406341386a5c25d523c7A500841b3E307 Code https://github.com/jaydippatel83/worldwidelink/blob/master/smart_contracts/airdrop/AirdropFactory.sol Line No: 1 - 126
Proof of Reserve Monitoring BTC.b's PoR triggers alerts and maintains on-chain reputation by tracking Avalanche's collateral ratio. Users receive email alerts for low ratios, and frequent imbalances reduce the pool's reputation.	Avalanche (Proof of Reserve) https://testnet.snowtrace.io/address/0xe28F1cfe684e907fdb9cC815b50a5dBF5350d007 Code: https://github.com/jaydippatel83/worldwidelink/blob/master/smart_contracts/sos-alert-contracts/ProofOfReserve.sol Line No: 1 - 105
Functions We attempted using functions for email notifications via a POST API but faced a "custom error" when calling the function consumer contract. To resolve, we implemented the desired functionality through a Chainlink Node.	Mumbai https://mumbai.polygonscan.com/address/0x6Cf0473b429fE9919a6443D9fFF2c6A1aC897A5e Code: https://github.com/jaydippatel83/worldwidelink/blob/master/smart_contracts/sos-alert-contracts/FunctionsConsumerExample.sol Line No: 1 - 112
Node-External Adapter We created an external adapter, bridged it with the node, and generated a job ID for the POST API of email and automated it as per Chainlink Automation - Keeper.	Mumbai(External Request) https://mumbai.polygonscan.com/address/0x403227Ba96250eaD0f12ba77951d7f65F9E5962d Code: https://github.com/jaydippatel83/worldwidelink/blob/master/smart_contracts/sos-alert-contracts/ExternalRequestContract.sol Line No: 1 - 122 https://github.com/mansijoshi17/cl-external-adapter
The GraphCreated a subgraph to retrieve user transactions from cross-chain lending/borrowing contracts and rewarded them with an airdrop of WWL tokens.	Sub Graph: https://api.studio.thegraph.com/query/44401/wwl/0.0.1 Code: https://github.com/jaydippatel83/worldwidelink/blob/master/src/jsx/components/Dashboard/widgets/Airdrop.js Line No: 15 to 30

Implementation Details:

Chainlink CCIP:

- Cross-Chain Escrow allows buyers and sellers to stake crypto assets in Ethereum, Avalanche, or Polygon without the need to have assets on the same chain as the other party.
- Cross-Chain Lending and Borrowing allow users to lend assets on Avalanche, Ethereum, or Polygon. Users can borrow assets on other chains based on the collateral ratio, eliminating the need for bridges or concerns about managing native gas tokens.
- Cross-Chain Liquid Staking enables users to stake assets, such as CCIP, on Avalanche Fuji and receive StCCIP on Polygon. Users can utilize their liquid assets for various DeFi use cases.
- Cross-Chain asset transfer between CCIP supported chains: Ethereum, Avalanche, or Polygon.

Chainlink Automation:

• We have used logic-based automation in 1) Automated SOS email and 2) SOS-triggered automated crypto asset transfers. Chainlink Automation in WWL involves logic-based alerts and transfers. Trigger 2 sends email alerts to specified loved ones if no Dapp interaction within days. Triggers 3 auto-transfer assets to loved ones' addresses if no WWL activity after user-configured time, preventing crypto wealth from being locked for a lifetime in case of emergencies.

Chainlink Data Feeds:

• Currently, CCIP supports only CCIP token so we have used price feeds in the Lending / Borrowing part of Dapp to fetch a price of Ethereum and Matic and peg 1 CCIP:1 Eth in Ethereum network and 1 CCIP: 1 Matic in the Polygon network and allow the user to borrow WDai accordingly supplied collateral of CCIP.

Chainlink VRF:

• To airdrop WWL tokens to an early user who interacted with any of the contracts from Escrow, Lend/Borrow, and Liquid Staking.

Chainlink Proof of Reserves:

• We monitor PoR for BTC.b to trigger vital alerts and maintain the on-chain reputation score by fetching the collateral ratio of Bitcoin on Avalanche. Users receive email alerts if the collateral ratio falls below the predefined percentage. Frequent imbalances lower the reputation score of the specific pool.

Chainlink Functions:

• We tried to utilize functions to implement notifications through a POST API for sending emails. However, we encountered a "custom error" when calling the function consumer contract. To address this issue, we created a Chainlink Node to implement the desired functionality.

Chainlink Node - External Adapter:

• We created an external adapter, bridged it with the node, and generated a job ID for the POST API of email and automated it as per Chainlink Automation - Keeper.

Challenges we ran into

🚧 We tried to utilize functions to implement notifications through a POST API for sending emails. However, we encountered a "custom error" when calling the function consumer contract. To address this issue, we created a Chainlink Node to implement the desired functionality 🛠️

Things we learned

💡This marks our first foray into building a product with a cross-chain-first approach. The development of WWL was greatly facilitated by referencing Chainlink's documentation, along with insights gained from video sessions at Smartcon and expert discussions during the hackathon. This process helped us comprehend the "Why, What, and How" behind CCIP and other Chainlink services.

What's Next for WorldWideLink

The cross-chain approach opens up new doors for the growth of the DeFi space. We can't imagine a world where we can only connect with users on the same cellular network that we use. Similarly, at this early stage, WorldWideLink has huge potential to build solutions in the DeFi space on top of CCIP, providing an easy and secure way to develop cross-chain compatible products.

🚀 We aspire to continue building worldwidelink.xyz, and it would be invaluable to receive guidance on developing a product with regulatory market fit without compromising user privacy and data protection. 🔒

For more details about Avalanche - https://github.com/jaydippatel83/worldwidelink/blob/master/chainlink.md

To get more details about chainlink implementation check - https://github.com/jaydippatel83/worldwidelink/blob/master/chainlink.md