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USYC subscriptions and redemptions are handled through an audited smart contract, callable from Solidity, TypeScript, or directly using the Etherscan interface.

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Solidity

Solidity
import "../IERC20.sol";

interface ITeller {
  function buy(uint256 _amount) external returns (uint256);
  function sell(uint256 _amount) external returns (uint256);
}

ITeller teller = ITeller(0x5C73E1cfdD85b7f1d608F7F7736fC8C653513B7A);

// Subscribe to USYC
IERC20 usdc = IERC20(0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48);
uint256 paying = 100 * 1e6; // 100.000000 USDC
usdc.approve(address(teller), paying);
uint256 usycPurchased = teller.buy(paying);

// Redeem USYC
IERC20 usyc = IERC20(0x136471a34f6ef19fE571EFFC1CA711fdb8E49f2b);
uint256 selling = 100 * 1e6; // 100.000000 USYC
usyc.approve(address(teller), selling);
uint256 usdcPayout = teller.sell(selling);

​
TypeScript

Typescript
import { Address, erc20ABI, writeContract } from "@wagmi/core";

const USYC_TELLER_ABI = [
  {
    inputs: [{ internalType: "uint256", name: "_amount", type: "uint256" }],
    name: "sell",
    outputs: [{ internalType: "uint256", name: "", type: "uint256" }],
    stateMutability: "nonpayable",
    type: "function",
  },
  {
    inputs: [{ internalType: "uint256", name: "_amount", type: "uint256" }],
    name: "buy",
    outputs: [{ internalType: "uint256", name: "", type: "uint256" }],
    stateMutability: "nonpayable",
    type: "function",
  },
] as const;

// Ethereum mainnet addresses
const USYC_TELLER_ADDRESS: Address =
  "0x5C73E1cfdD85b7f1d608F7F7736fC8C653513B7A";
const USDC_ADDRESS: Address = "0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48";
const USYC_ADDRESS: Address = "0x136471a34f6ef19fE571EFFC1CA711fdb8E49f2b";

const ONE_HUNDRED_USDC = BigInt(100_000000); // USDC uses 6 decimals
const ONE_HUNDRED_USYC = BigInt(100_000000); // USYC uses 6 decimals

// Subscribe to USYC
export const approveUSYCTellerToSpendUSDC = () =>
  writeContract({
    chainId: 1,
    address: USDC_ADDRESS,
    abi: erc20ABI,
    functionName: "approve",
    args: [USYC_TELLER_ADDRESS, ONE_HUNDRED_USDC],
  });

export const buyUSYC = () =>
  writeContract({
    address: USYC_TELLER_ADDRESS,
    chainId: 1,
    abi: USYC_TELLER_ABI,
    functionName: "buy",
    args: [ONE_HUNDRED_USDC],
  });

// Redeem USYC
export const approveUSYCTellerToSpendUSYC = () =>
  writeContract({
    chainId: 1,
    address: USYC_ADDRESS,
    abi: erc20ABI,
    functionName: "approve",
    args: [USYC_TELLER_ADDRESS, ONE_HUNDRED_USYC],
  });

export const sellUSYC = () =>
  writeContract({
    address: USYC_TELLER_ADDRESS,
    chainId: 1,
    abi: USYC_TELLER_ABI,
    functionName: "sell",
    args: [ONE_HUNDRED_USYC],
  });

​
Etherscan

You can use the Etherscan interface to subscribe to and redeem USYC.

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Subscribing to USYC

Before subscribing to USYC, you must approve the Teller contract to spend your USDC.
  1. Go to the USDC contract and click Write as Proxy.
  2. Scroll to the approve function.
  3. In the spender field, enter 0x5C73E1cfdD85b7f1d608F7F7736fC8C653513B7A (the Teller address).
  4. In the amount field, enter the amount of USDC to spend.
After setting the allowance, you can subscribe to USYC:
  1. Go to the Teller contract and click Write as Proxy.
  2. Scroll to the buy function.
  3. Enter the amount of USDC to convert to USYC.

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Redeeming USYC

Before redeeming USYC, you must approve the Teller contract to spend your USYC.
  1. Go to the USYC contract and click Write as Proxy.
  2. Scroll to the approve function.
  3. In the spender field, enter 0x5C73E1cfdD85b7f1d608F7F7736fC8C653513B7A (the Teller address).
  4. In the amount field, enter the amount of USYC to redeem.
After setting the allowance, you can redeem USYC:
  1. Go to the Teller contract and click Write as Proxy.
  2. Scroll to the sell function.
  3. Enter the amount of USYC to convert to USDC.
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