JAY Protocol ‐ Core Contracts

     

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Overview

The JAY Protocol is a minimal, single‑asset DeFi ecosystem built around a fixed‑supply ERC‑20 token (JayToken) and a paired Vendor contract that provides on‑chain buy/sell functionality at a constant rate.
Designed for institutional‑grade liquidity without order books, the protocol enables:

• Zero‑fee, fixed‑rate swaps between ETH and JAY.
• A simple “cash‑register” model where the vendor always maintains a token balance and ETH reserve.
• Owner‑controlled profit extraction and unsold token recovery.

The contracts are written in Solidity 0.8.x and leverage OpenZeppelin’s battle‑tested libraries. Deployment is managed via Hardhat Ignition; tests use the Hardhat network and Ethers‑js.

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Core Architecture

• contracts/JayToken.sol

  • Extends ERC20 from OpenZeppelin.
  • mints 1 000 000 JAY (18 decimals) to the deployer on construction.
  • No owner‑only privileges or pausing – pure, immutable token policy.

• contracts/Vendor.sol

  • tokenPerETH fixed at 500 JAY per ETH.
  • buyTokens()
    • payable entry point.
    • require(msg.value > 0) and sufficient vendor token balance.
    • Transfers tokens directly (token.transfer).
    • Emits BuyTokens event.
  • sellTokens(uint256)
    • Checks user balance and vendor ETH reserve.
    • Uses token.transferFrom (user must approve first).
    • Sends ETH with low‑level call and checks return value.
    • Emits SellTokens event.
  • withdrawETH() / withdrawTokens()
    • onlyOwner modifier guards; owner set in constructor.
    • Allows profit withdrawal and recovery of unsold tokens.
  • Access control via onlyOwner modifier.
  • Comprehensive require guards prevent reverts and bad state.

• Deployment (see ignition/modules/Deploy.js & JayProject.js)

  • Ignition module automatically deploys JayToken and Vendor.
  • After deployment transfers 500 000 JAY (×10¹⁸) to the vendor as inventory.

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Local Development

1. Clone & install dependencies

   git clone <repo-url>
   cd jay-token-contracts
   npm install

2. Compile

   npx hardhat compile

3. Run the test suite

   npx hardhat test
   # with gas report
   REPORT_GAS=true npx hardhat test

   Tests are located in test/JayToken.js and cover the core buy‑flow, including:

   • ERC‑20 transfer of initial supply.
   • Buying tokens with 1 ETH → 500 JAY.
   • Balance assertions via Chai expect.

4. Run a local node

   npx hardhat node

   Use the generated accounts in scripts or the console.

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Deployment & Verification

Configuration

The project uses hardhat.config.js:

solidity: "0.8.20",
networks: {
  localhost: { url: "[http://127.0.0.1:8545](http://127.0.0.1:8545)" },
  sepolia: {
    url: process.env.INFURA_RPC_URL || "",
    accounts: process.env.PRIVATE_KEY ? [process.env.PRIVATE_KEY] : []
  }
},
etherscan: { apiKey: process.env.ETHERSCAN_API_KEY }

Set the following environment variables in a .env file:

INFURA_RPC_URL=…
PRIVATE_KEY=0x…
ETHERSCAN_API_KEY=…

Deploying

Using Hardhat Ignition (recommended for deterministic deployments):

npx hardhat ignition deploy ./ignition/modules/Deploy.js --network sepolia

or, if you use the alternative module:

npx hardhat ignition deploy ./ignition/modules/JayProject.js --network sepolia

The output will include the deployed addresses for both contracts.

– you can also write ad‑hoc scripts using ethers.getContractFactory if preferred.

Verifying on Etherscan

npx hardhat verify --network sepolia <JayToken_address>
 npx hardhat verify --network sepolia <Vendor_address> <JayToken_address>

Example address table (replace with actual values):

Contract	Sepolia Address	Notes
JayToken	0xd8A13966F86d917f0D3892f68BDf729655E9544a	ERC‑20 token
Vendor	0xA23E3136523281be93e85FBd9EB9B6d282C1A913	Swap/market maker

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Security & Auditing

The test suite exercises the core economic flows; additional coverage may be added for:

• Selling tokens (requires approve).
• Owner withdrawal edge cases.
• Handling of zero/overflow values (Solidity 0.8 handles safe math).

Contracts depend on OpenZeppelin’s audited libraries and employ explicit require statements for all user inputs and state changes.
Deployment via Ignition provides reproducible bytecode.
A formal audit should review:

• Reentrancy (use of call to send ETH).
• Pricing logic and rounding behaviour.
• Access control (onlyOwner) and constructor initialization.

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This repository constitutes the formal smart‑contract core of the JAY Protocol. It is intended for use as a foundation for wallets, front‑ends, and further DeFi extensions. All commands above assume a Unix‑style shell; adjust accordingly for Windows.

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👨‍💻 Author

Developed by Zaidan.
I am an active Information Technology student at Institut Teknologi Indonesia (ITI) with a solid foundation in programming, system administration, and general IT problem-solving. I am currently looking for part-time opportunities to apply my technical skills.

• GitHub: @MuhammadZaidan1
• LinkedIn: muhammad zaidan
• Email: muhammadzaidanf123@gmail.com