Read Latest Price

With your contract configured and the interface installed, reading a price is a single view call. This page covers three reading patterns: single asset, batch, and derived pairs. Use whichever fits your protocol’s needs — or combine them.

Single Asset Price

The most common pattern. Call getAssetInfo with a bytes32 asset ID and read the returned PriceFeed struct.

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

import "ifapricefeed-interface/IIfaPriceFeed.sol";

contract PriceConsumer {
    IIfaPriceFeed public constant ORACLE =
        IIfaPriceFeed(0xA9F17344689C2c2328F94464998db1d3e35B80dC); // Base Mainnet

    bytes32 public constant USDT_ASSET_ID =
        0x6ca0cef6107263f3b09a51448617b659278cff744f0e702c24a2f88c91e65a0d;

    function getUSDTPrice()
        external
        view
        returns (
            int256  price,
            int8    decimal,
            uint256 lastUpdateTime
        )
    {
        (IIfaPriceFeed.PriceFeed memory info, bool exists) =
            ORACLE.getAssetInfo(USDT_ASSET_ID);

        require(exists, "IFA: asset not supported");

        return (info.price, info.decimal, info.lastUpdateTime);
    }
}

What each field means:

Field	Type	Description
`price`	`int256`	Scaled price value. Divide by `10^(-decimal)` to get the human-readable price.
`decimal`	`int8`	Negative scaling exponent. Stablecoin feeds use `-18` — meaning divide by `1e18`.
`lastUpdateTime`	`uint256`	Unix timestamp of the last on-chain update from the relayer network.

Converting to a human-readable price:

// For a fixed -18 decimal (all current stablecoin feeds)
uint256 humanPrice = uint256(info.price) / 1e18;

// For dynamic decimal handling (future-proof)
uint256 humanPrice = uint256(info.price) / (10 ** uint8(-info.decimal));

For a USDT feed at peg, expect info.price ≈ 1000000000000000000 (1e18) and info.decimal = -18, giving a human-readable price of $1.00.

Batch Price Read

If your protocol needs multiple prices in the same transaction — for example, valuing a multi-asset collateral basket — use getAssetsInfo. One external call is always cheaper than multiple individual calls.

bytes32[] memory assetIds = new bytes32[](3);
assetIds[0] = USDT_ASSET_ID;
assetIds[1] = USDC_ASSET_ID;
assetIds[2] = CNGN_ASSET_ID;

(IIfaPriceFeed.PriceFeed[] memory infos, bool[] memory exists) =
    ORACLE.getAssetsInfo(assetIds);

for (uint256 i = 0; i < assetIds.length; i++) {
    require(exists[i], "IFA: unsupported asset in batch");
    // Process infos[i].price, infos[i].decimal, infos[i].lastUpdateTime
}

The exists array is returned in the same order as the input assetIds array. Always check exists[i] before using infos[i] — a false value means that asset has no data and the corresponding PriceFeed fields will be zero.

Derived Pair Prices

Derived pairs let you price one supported asset directly against another — for example, CNGN priced in USDT terms, or BRZ priced in USDC terms — without requiring a dedicated feed for every possible combination. IFÁ Labs computes derived prices on-chain using the two underlying USD feeds as intermediates.

Single Derived Pair

// Price CNGN in terms of USDT (how much USDT is one CNGN worth?)
IIfaPriceFeed.DerivedPair memory pair = ORACLE.getPairbyId(
    CNGN_ASSET_ID,   // asset0 — the asset being priced
    USDT_ASSET_ID,   // asset1 — the denominator
    IIfaPriceFeed.PairDirection.Forward
);

Batch Derived Pairs

For protocols working across multiple cross-asset pairs:

bytes32[] memory assets0 = new bytes32[](2);
bytes32[] memory assets1 = new bytes32[](2);

assets0[0] = CNGN_ASSET_ID;
assets1[0] = USDT_ASSET_ID;

assets0[1] = BRZ_ASSET_ID;
assets1[1] = USDC_ASSET_ID;

// Forward direction — asset0 priced in asset1 terms
IIfaPriceFeed.DerivedPair[] memory pairs =
    ORACLE.getPairsbyIdForward(assets0, assets1);

Understanding PairDirection

Direction	Meaning	Use Case
`Forward`	asset0 priced in asset1 terms	”How much USDT is one CNGN worth?”
`Backward`	asset1 priced in asset0 terms	”How much CNGN is one USDT worth?”

Derived pairs require both assets to have active, non-stale USD feeds. If either underlying feed is stale or missing, the derived pair calculation will revert. Always ensure both feeds are healthy before calling derived pair functions in critical paths.

Reading Prices Off-Chain

For backend services, scripts, or frontend applications reading prices without executing a transaction:

const { ethers } = require("ethers");

const ORACLE_ADDRESS = "0xA9F17344689C2c2328F94464998db1d3e35B80dC";
const provider = new ethers.JsonRpcProvider("https://mainnet.base.org");

const ABI = [
  `function getAssetInfo(bytes32 assetId)
      view returns (
          (int256 price, int8 decimal, uint256 lastUpdateTime) assetInfo,
          bool exists
      )`,
  `function getAssetsInfo(bytes32[] assetIds)
      view returns (
          (int256 price, int8 decimal, uint256 lastUpdateTime)[] infos,
          bool[] exists
      )`
];

const oracle = new ethers.Contract(ORACLE_ADDRESS, ABI, provider);

async function readPrice(assetId) {
    const [info, exists] = await oracle.getAssetInfo(assetId);

    if (!exists) throw new Error("Asset not supported");

    const price = Number(info.price) / 10 ** Number(-info.decimal);
    const ageSeconds = Math.floor(Date.now() / 1000) - Number(info.lastUpdateTime);

    return {
        price:       price.toFixed(6),
        decimal:     Number(info.decimal),
        ageSeconds,
        rawPrice:    info.price.toString(),
    };
}

// Single read
const usdt = await readPrice(
    "0x6ca0cef6107263f3b09a51448617b659278cff744f0e702c24a2f88c91e65a0d"
);
console.log(usdt);
// { price: '1.000124', decimal: -18, ageSeconds: 412, rawPrice: '1000124000000000000' }

Common Mistakes

These are the mistakes developers make most often when first reading from the oracle. All of them are avoidable. Not checking exists before using the price. If exists is false, info.price is 0. Using that value without checking will silently execute your logic against a zero price. Forgetting to apply the decimal scaling. info.price is not a dollar amount — it’s a scaled integer. 1000000000000000000 is $1.00, not one quintillion dollars. Always divide by 10^(-decimal) before using the value in human-facing output or fixed-point math. Casting int256 to uint256 without checking sign. Current stablecoin feeds always return positive prices, but the type is int256. Cast safely: only cast after confirming info.price > 0, or use uint256(info.price) with the understanding that negative values would underflow. Using the price without a staleness check. A returned price with exists = true is not automatically fresh. Always pair your read with a lastUpdateTime check before using the value in any logic with financial consequences. See Verify Price Integrity.

INTRODUCTION

QUICKSTART

INTEGRATION GUIDES

CORE CONCEPTS

ONCHAIN REFERENCE

SECURITY & AUDITS

ADVANCED TOPICS

TROUBLESHOOTING

REFERENCE

SUPPORT & COMMUNITY

Single Asset Price

Batch Price Read

Derived Pair Prices

Single Derived Pair

Batch Derived Pairs

Understanding PairDirection

Reading Prices Off-Chain

Common Mistakes

Next Steps

Handle Stale Data

Gas Optimization Tips

​Single Asset Price

​Batch Price Read

​Derived Pair Prices

​Single Derived Pair

​Batch Derived Pairs

​Understanding PairDirection

​Reading Prices Off-Chain

​Common Mistakes

​Next Steps

Handle Stale Data

Gas Optimization Tips

Single Asset Price

Batch Price Read

Derived Pair Prices

Single Derived Pair

Batch Derived Pairs

Understanding PairDirection

Reading Prices Off-Chain

Common Mistakes

Next Steps