OpenPayPriceFeed

The OpenPayPriceFeed contract aggregates price data from Chainlink decentralized oracles to convert between USD and token amounts. It includes stablecoin shortcuts and staleness protection. Address (BSC Testnet): 0x1f34e070D4BB1eD3AaF37D8E3297b0a9A12a3399 Explorer: View on BscScan

How It Works

Key Design Decisions

Stablecoin Shortcut

Tokens marked as stablecoins (USDT, USDC) skip the oracle call entirely and return a fixed price of $1.00 (represented as 100000000 with 8 decimals). This saves gas and avoids unnecessary oracle dependencies.

Staleness Protection

The contract rejects price data older than the stalenessThreshold (default: 3600 seconds / 1 hour). If the Chainlink oracle has not updated within this window, all price queries revert with “Stale price”.

Native Token Support

BNB (native token, address(0)) uses a dedicated nativeFeed Chainlink oracle rather than the token config mapping. This is set separately via setNativeFeed().

Read Functions

getPrice

Get the current USD price and decimal precision for a token.

function getPrice(address token) external view returns (
    uint256 price,
    uint8 decimals_
)

Parameter	Type	Description
`token`	`address`	Token address, or `address(0)` for native BNB

Return Value	Type	Description
`price`	`uint256`	USD price (scaled by 10^decimals)
`decimals_`	`uint8`	Price decimal precision (typically 8 for Chainlink)

Behavior:

For stablecoins: returns (100000000, 8) — equivalent to $1.00
For address(0): queries the nativeFeed Chainlink oracle
For other tokens: queries the token-specific Chainlink feed

getAmountInToken

Convert a USD amount to the equivalent token amount at the current price.

function getAmountInToken(address token, uint256 usdAmount) external view returns (uint256)

Parameter	Type	Description
`token`	`address`	Token address
`usdAmount`	`uint256`	USD amount to convert

Example: “How many BNB tokens do I need to pay $25?“

getAmountInUsd

Convert a token amount to its USD equivalent at the current price.

function getAmountInUsd(address token, uint256 tokenAmount) external view returns (uint256)

Parameter	Type	Description
`token`	`address`	Token address
`tokenAmount`	`uint256`	Token amount to convert

Example: “How much USD is 0.5 BNB worth?”

Token Configuration

configureToken

function configureToken(address token, address feed, bool isStablecoin) external onlyOwner

Parameter	Type	Description
`token`	`address`	ERC-20 token address
`feed`	`address`	Chainlink price feed address (can be `address(0)` for stablecoins)
`isStablecoin`	`bool`	If `true`, returns fixed $1.00 price without oracle call

Example configurations:

// USDT - stablecoin, no oracle needed
priceFeed.configureToken(usdtAddress, address(0), true);

// USDC - stablecoin, no oracle needed
priceFeed.configureToken(usdcAddress, address(0), true);

// WBNB - volatile, needs Chainlink feed
priceFeed.configureToken(wbnbAddress, bnbUsdFeed, false);

tokenConfigs

Read the configuration for a registered token.

function tokenConfigs(address token) external view returns (
    address feed,
    bool isStablecoin,
    bool isConfigured
)

Admin Functions (Owner Only)

setNativeFeed

Set the Chainlink price feed for the native token (BNB).

function setNativeFeed(address feed) external onlyOwner

setStalenessThreshold

Set the maximum age (in seconds) for oracle price data. Minimum: 60 seconds.

function setStalenessThreshold(uint256 threshold) external onlyOwner

Setting the threshold too low may cause price queries to fail frequently during periods of low oracle update frequency. The default of 3600 seconds (1 hour) is appropriate for most use cases.

State Variables

Variable	Type	Default	Description
`nativeFeed`	`address`	—	Chainlink BNB/USD feed address
`stalenessThreshold`	`uint256`	`3600`	Max oracle data age in seconds

Events

event TokenConfigured(address indexed token, address feed, bool isStablecoin);
event NativeFeedUpdated(address oldFeed, address newFeed);
event StalenessUpdated(uint256 oldThreshold, uint256 newThreshold);

Example: Querying Prices with ethers.js

import { ethers } from "ethers";

const provider = new ethers.JsonRpcProvider("https://data-seed-prebsc-1-s1.bnbchain.org:8545");

const priceFeed = new ethers.Contract(
  "0x1f34e070D4BB1eD3AaF37D8E3297b0a9A12a3399",
  [
    "function getPrice(address) view returns (uint256 price, uint8 decimals_)",
    "function getAmountInToken(address, uint256) view returns (uint256)",
    "function getAmountInUsd(address, uint256) view returns (uint256)",
  ],
  provider
);

// Get BNB/USD price
const [price, decimals] = await priceFeed.getPrice(ethers.ZeroAddress);
console.log(`BNB price: $${ethers.formatUnits(price, decimals)}`);

// How much BNB for $50?
const bnbAmount = await priceFeed.getAmountInToken(
  ethers.ZeroAddress,
  ethers.parseUnits("50", 8) // USD with 8 decimals
);
console.log(`BNB needed for $50: ${ethers.formatEther(bnbAmount)}`);

Chainlink Price Feeds Reference

For mainnet deployment, use the official Chainlink BSC feeds:

Pair	Mainnet Feed	Testnet
BNB/USD	`0x0567F2323251f0Aab15c8dFb1967E4e8A7D42aeE`	MockPriceFeed
BTC/USD	`0x264990fbd0A4796A3E3d8E37C4d5F87a3aCa5Ebf`	MockPriceFeed
ETH/USD	`0x9ef1B8c0E4F7dc8bF5719Ea496883DC6401d5b2e`	MockPriceFeed

Find all available Chainlink feeds at data.chain.link.

​OpenPayPriceFeed

​How It Works

​Key Design Decisions

​Read Functions

​getPrice

​getAmountInToken

​getAmountInUsd

​Token Configuration

​configureToken

​tokenConfigs

​Admin Functions (Owner Only)

​setNativeFeed

​setStalenessThreshold

​State Variables

​Events

​Example: Querying Prices with ethers.js

​Chainlink Price Feeds Reference

OpenPayPriceFeed

How It Works

Key Design Decisions

Read Functions

getPrice

getAmountInToken

getAmountInUsd

Token Configuration

configureToken

tokenConfigs

Admin Functions (Owner Only)

setNativeFeed

setStalenessThreshold

State Variables

Events

Example: Querying Prices with ethers.js

Chainlink Price Feeds Reference