Smart Contracts

Source Code & Audits

• Contract Source Code: https://github.com/ur-app/ur-contracts

• Audit Reports: https://github.com/ur-app/ur-contracts/tree/main/Audits

Environment

Most of UR's core functionalities, including account management and card operations, are deployed and executed exclusively on the Mantle Network. Interactions with other chains (such as Ethereum, Arbitrum, Base, and Monad) are only required for specific features like Deposit and Cash to Crypto.

For deployment, we recommend using QuickNode or Alchemy as your RPC provider.

Mantle Mainnet

• Chain ID: 5000

• RPC Endpoint: https://rpc.mantle.xyz

Mantle Sepolia Testnet

• Chain ID: 5003

• RPC Endpoint: https://rpc.sepolia.mantle.xyz

Chain Explorers

Network	Mainnet	Testnet
Mantle	https://mantlescan.xyz/	https://sepolia.mantlescan.xyz/
Ethereum	https://etherscan.io/	https://sepolia.etherscan.io/
Arbitrum One	https://arbiscan.io/	https://sepolia.arbiscan.io/
Base	https://basescan.org/	https://sepolia.basescan.org/
BSC	https://bscscan.com/	https://testnet.bscscan.com/
Monad	https://monadscan.com/	https://testnet.monadscan.com/

Functions

Account

Our account model is based on the ERC721 NFT standard; each user has a unique UR ID (Token ID) that identifies and manages their assets and permissions on the UR platform. The user's KYC status is recorded in the contract's status mapping, with each status corresponding to a numeric value as follows:

Contract Addresses

Network	Address
Mainnet	0x4a05148119683E0A41b52fb973EEF0EE81536c47
Testnet	0xfE6fB4aE524c8f032E14691C3B2465cc5bcB9677

Methods

Function Name	Description
ownerOf	Query EVM wallet address by URID.
tokenOfOwnerByIndex	Query URID by EVM wallet address. This ERC721Enumerable method returns the token ID owned by an address at a given index. Since each user should hold one Account NFT, use index = 0 to get the user's URID.
status	Status: KYC passed, status is Live. Functions for non-Live statuses are restricted. SoftBlocked, // 1 Tourist, // 2 Blocked, // 3 Closed, // 4 Live // 5
limit	Query user monthly transaction limit by URID. All outgoing Fiat transactions count towards this limit. For KYC-verified users, the default monthly limit is 100,000 CHF. Returns usedLimit (uint256), clientLimit (uint256), startLimitDate (uint256). Users receive a spending limit that refreshes every 30 days. - usedLimit (uint256): Amount of the limit already used in the current 30-day cycle. This value is reset every 30 days. - clientLimit (uint256): Total allowed limit for the current 30-day period. - startLimitDate (uint256): Timestamp of the last limit reset (start time of the current 30-day cycle).

ABI

Fiat24Account.sol

Example: Get URID by Wallet Address (TypeScript + viem)

import { createPublicClient, http, parseAbi } from 'viem'
import { mantle } from 'viem/chains'

const client = createPublicClient({
  chain: mantle,
  transport: http('https://rpc.mantle.xyz')
})

const abi = parseAbi([
  'function tokenOfOwnerByIndex(address owner, uint256 index) view returns (uint256)'
])

const accountContractAddress = '0x4a05148119683E0A41b52fb973EEF0EE81536c47'
const userAddress = '0x...' // Replace with the user's wallet address

async function getUrid() {
  try {
    const tokenId = await client.readContract({
      address: accountContractAddress,
      abi: abi,
      functionName: 'tokenOfOwnerByIndex',
      args: [userAddress, 0n]
    })

    console.log(`URID: ${tokenId.toString()}`)
  } catch (error) {
    console.error('Error fetching URID:', error)
  }
}

getUrid()

Fiat Balance

Contract Addresses

Currency	Mainnet	Testnet
USD	0xD598839598bBF508b97697b7D9e80054D4bcaaCC	0xdf79470986629ae4893BfCE0c6C0F4d085E99741
EUR	0x0578be9C858e6562dd8cd11a738b89Ca48194dA5	0x5E52c8993283023B83e87eF577f7f51Fa1c5B00
CHF	0x53587A05ccDdCE555C2Cd7cE4C9c5Bc3D912E2f3	0x52837070C96C6D5E23ed90a43479c0237c41864c
CNH	0xa0af0C397CB0A52F5E8Bc7BB89068dDDfaE9F211	0x4AfbC767e6d310296657b7759a5F2c303F26B327
SGD	0x8F7F92F2A0247cc8660C4C4EF69582Bc6849B4d9	0x2FEb2d95ce8eC88931c4031cdd2875C90EDC87FE
JPY	0x3bC9fC0460cAC2DdD352848ECc0BFe204c220717	0x8af3be43607cb1e57b6e37fda99b6b988c5b48f0
HKD	0x64266a15432004708e5fCA0239f664d069853374	0x30c94bCF88c5c8f3Ff08F38242a38C656Bb28a6d

Methods

Method	Description
balanceOf	Query a user's fiat token balance by their address.
decimals	Precision of the token. For example, if decimals equals 2, a balance of 505 tokens should be displayed to a user as 5.05 (505 / 10 ** 2).
allowance	This function can be used to query the amount a user has approved for a given spender. Generally, for an unlimited approval, we call the approve method with value set to the maximum of uint256, i.e. 2^256-1.

ABI

Fiat24Token.sol

Example: Get Balance (TypeScript + viem)

import { createPublicClient, http, parseAbi, formatUnits } from 'viem'
import { mantle } from 'viem/chains'

// 1. Create a client connected to Mantle Mainnet
const client = createPublicClient({
  chain: mantle,
  transport: http('https://rpc.mantle.xyz')
})

// 2. Define the ABI for balanceOf and decimals
const abi = parseAbi([
  'function balanceOf(address owner) view returns (uint256)',
  'function decimals() view returns (uint8)'
])

// 3. Contract and User addresses
const eurContractAddress = '0x0578be9C858e6562dd8cd11a738b89Ca48194dA5' // EUR on Mantle Mainnet
const userAddress = '0x...' // Replace with the user's wallet address

async function getBalance() {
  try {
    // 4. Read contract data
    const [balance, decimals] = await Promise.all([
      client.readContract({
        address: eurContractAddress,
        abi: abi,
        functionName: 'balanceOf',
        args: [userAddress]
      }),
      client.readContract({
        address: eurContractAddress,
        abi: abi,
        functionName: 'decimals'
      })
    ])

    // 5. Format and display the balance
    console.log(`Raw Balance: ${balance}`)
    console.log(`Decimals: ${decimals}`)
    console.log(`Formatted Balance: ${formatUnits(balance, decimals)} EUR`)
    
  } catch (error) {
    console.error('Error fetching balance:', error)
  }
}

getBalance()

Money Transfer

Contract Addresses

Contract refers to the currency contracts.

Methods

Note: Only users in Live status (status == 5) are allowed to transfer their fiat tokens out in any form.

Method	Description
transfer	Transfer fiat token to any EVM address.
transferByAccountId	Transfer fiat tokens to the target user by their URID.
clientPayout	User to transfer their currency out via bank transfer to a UR-supported bank account. Before the user calls this contract function, a payout account (contactId) must be created through UR's API (The API is coming soon).

Example: Transfer Fiat (TypeScript + viem)

import { createWalletClient, http, parseAbi, parseUnits } from 'viem'
import { privateKeyToAccount } from 'viem/accounts'
import { mantle } from 'viem/chains'

// 1. Setup Wallet Client (Required for write operations)
// ⚠️ NEVER hardcode private keys in production code
const account = privateKeyToAccount('0x...') 
const client = createWalletClient({
  account,
  chain: mantle,
  transport: http('https://rpc.mantle.xyz')
})

// 2. Define ABI for transfer
const abi = parseAbi([
  'function transfer(address to, uint256 amount) returns (bool)'
])

// 3. Configuration
const eurContractAddress = '0x0578be9C858e6562dd8cd11a738b89Ca48194dA5' // EUR Contract
const recipientAddress = '0x...' // Receiver's address
const amountToSend = '10' // Amount in EUR

async function transferFiat() {
  try {
    // 4. Send Transaction
    // Note: Ensure the sender has enough balance and ETH(MNT) for gas
    const hash = await client.writeContract({
      address: eurContractAddress,
      abi: abi,
      functionName: 'transfer',
      args: [
        recipientAddress, 
        parseUnits(amountToSend, 2) // Assuming 2 decimals for EUR
      ]
    })

    console.log(`Transaction sent! Hash: ${hash}`)
  } catch (error) {
    console.error('Transfer failed:', error)
  }
}

transferFiat()

Money Exchange

Also known as foreign-exchange conversion, used for exchanging between fiat currencies.

Contract Addresses

Network	Address
Mantle Mainnet	0x9F88e04D129d4a4247F009833ba0Bd5D8F6A2146
Mantle Sepolia Testnet	0x2C2E6BC745e583629a4157c2D8a9234d59F4067e

Methods

Note: Only users in Live status (status = 5) are allowed to do money exchange.

Method	Description
moneyExchangeExactIn	Exchange between 2 currencies
getExchangeRate	Query the exchange rate between two specified currency token addresses.

ABI

Fiat24CryptoRelay.sol

Example: Money Exchange (TypeScript + viem)

This process involves two steps:

1. Query the current exchange rate using getExchangeRate.

2. Execute the exchange using moneyExchangeExactin.

import { createPublicClient, createWalletClient, http, parseAbi, parseUnits, formatUnits } from 'viem'
import { privateKeyToAccount } from 'viem/accounts'
import { mantle } from 'viem/chains'

// 1. Setup Clients
const account = privateKeyToAccount('0x...')
const publicClient = createPublicClient({
  chain: mantle,
  transport: http('https://rpc.mantle.xyz')
})
const walletClient = createWalletClient({
  account,
  chain: mantle,
  transport: http('https://rpc.mantle.xyz')
})

// 2. Define ABI
const abi = parseAbi([
  'function getExchangeRate(address srcToken, address destToken) view returns (uint256)',
  'function moneyExchangeExactin(address srcToken, address destToken, uint256 srcAmount, uint256 minDestAmount) returns (uint256)'
])

// 3. Configuration
const exchangeContractAddress = '0x9F88e04D129d4a4247F009833ba0Bd5D8F6A2146'
const eurAddress = '0x0578be9C858e6562dd8cd11a738b89Ca48194dA5' // Source: EUR
const usdAddress = '0xD598839598bBF508b97697b7D9e80054D4bcaaCC' // Destination: USD
const amountInEur = '100' // Exchange 100 EUR

async function exchangeCurrency() {
  try {
    // 4. Step 1: Get Exchange Rate
    const rate = await publicClient.readContract({
      address: exchangeContractAddress,
      abi: abi,
      functionName: 'getExchangeRate',
      args: [eurAddress, usdAddress]
    })
    console.log(`Current Rate: ${formatUnits(rate, 18)}`) // Rate has 18 decimals

    // 5. Calculate Minimum Destination Amount (Slippage Protection)
    // Example: Allow 1% slippage
    const srcAmount = parseUnits(amountInEur, 2) // EUR has 2 decimals
    const expectedDestAmount = (srcAmount * rate) / parseUnits('1', 18)
    const minDestAmount = (expectedDestAmount * 99n) / 100n 

    // 6. Step 2: Execute Exchange
    const hash = await walletClient.writeContract({
      address: exchangeContractAddress,
      abi: abi,
      functionName: 'moneyExchangeExactin',
      args: [eurAddress, usdAddress, srcAmount, minDestAmount]
    })

    console.log(`Exchange submitted! Hash: ${hash}`)
  } catch (error) {
    console.error('Exchange failed:', error)
  }
}

exchangeCurrency()

Deposit (Off-ramp)

Contract Addresses

Network	Mainnet	Testnet
Mantle	0xd08B421A33F9b09A59E2ebf72afEF2365ce5b083	0xd6d4C6eB84697cB9bf0045e88b8f3A0bD42D3d66
Arbitrum	0xd08B421A33F9b09A59E2ebf72afEF2365ce5b083	0xCa8eFFac628001B86e068b8367174F91E7E88357
Ethereum	0xd08B421A33F9b09A59E2ebf72afEF2365ce5b083	0xF67b89d376D3aAA872E151B4526271D9394aE192
Base Network	0xd08B421A33F9b09A59E2ebf72afEF2365ce5b083	0xd6d4C6eB84697cB9bf0045e88b8f3A0bD42D3d66
Monad	0xd08B421A33F9b09A59E2ebf72afEF2365ce5b083	0x886DCF3BCb4fe8b2b07366C9F9aEbD3e471E8abA

Methods

Note: Only users with status Live (5) or SoftBlocked (1) can perform deposit(off-ramp) transactions.

Method	Description
depositTokenViaUsdc	The user deposits USDC into the contract and receives fiat currency in their UR account.
depositTokenViaAggregator	Supports users depositing a specific crypto asset and receiving fiat currency in their UR account. The prerequisite is that the frontend must integrate a DEX/aggregator API(API is coming soon) and construct the Crypto → USDC swap as calldata.

ABI

Fiat24CryptoDeposit.sol

Onramp

Contract Addresses

Network	Mainnet	Testnet
Mantle	0x2460634bf887A0F4E885278B93E10f91D48a5a8c
Arbitrum/Base/Ethereum/BSC	0xAACe017F0a6Bb9890E449d5b27fbcA9C440b81e9

Methods

ABI

BufferPool.sol

Card

Contract Addresses

Contract refers to the currency contracts.

Spender Contract (Card Authorization):

Network	Address
Mainnet	0xb9d38DDE25f67D57af5b91C254F869F90d483d05
Testnet	0x25d66C564532258eD9cdBB6215E260AFf41d8bae

Methods

To use the UR debit card, users must authorize the Spender Contract to spend their Fiat or USDe balance via approve or permit methods.

Method

Description

approve / permit

Authorize the Spender Contract to spend funds. The debit card payments are booked by the Spender contract via the authorize() function. Therefore, the card owner needs to approve a certain limit to the Spender contract for future card spendings. Supported Assets: - Fiat Tokens: Users must approve the corresponding Fiat token contract. - USDe: Users can also authorize USDe directly for consumption. Usage Notes: - Enable Authorization: It is common practice to approve the maximum uint256 value (2^256 - 1) to ensure uninterrupted service. - Revoke Authorization: To cancel the authorization, call the approve method with an amount of 0.

ABI

Fiat24Token.sol

Card Transaction Flow

Card Transaction Flow