Complete Example Contract

This page brings together every pattern covered in the EVM integration guides into a single, deployable contract. It is not a minimal example — it is a reference implementation you can use as a foundation for a real protocol. Read through it in full before adapting it. Every decision is intentional and annotated.

What This Contract Demonstrates

Pattern	Where It Appears
Constants for oracle address and asset IDs	Contract-level declarations
Single asset price read with full verification	`getVerifiedPrice`
Batch price read for multiple assets	`getMultipleVerifiedPrices`
Derived pair pricing	`getCrossAssetPrice`
Staleness check with per-asset thresholds	`_isFresh`
Peg deviation circuit breaker	`_isReasonable`
Protocol pause on oracle failure	`whenOracleHealthy` modifier
Cross-transaction price cache	`_getCachedPrice`
Graceful fallback on stale data	`getVerifiedPriceWithFallback`
Storage struct packing	`CachedPrice` struct

The Contract

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.29;

import "ifapricefeed-interface/IIfaPriceFeed.sol";

/// @title  IfaIntegrationReference
/// @notice Production-ready reference contract for IFÁ Labs oracle integration.
///         Demonstrates all recommended patterns for consuming stablecoin price feeds.
/// @dev    Adapt this contract to your protocol's needs. Do not deploy as-is
///         without reviewing all configuration constants for your specific use case.
contract IfaIntegrationReference {

    // -------------------------------------------------------------------------
    // Oracle Configuration
    // -------------------------------------------------------------------------

    /// @dev Oracle contract — Base Mainnet
    IIfaPriceFeed public constant ORACLE =
        IIfaPriceFeed(0xA9F17344689C2c2328F94464998db1d3e35B80dC);

    // Asset IDs — keccak256(abi.encodePacked("SYMBOL/USD"))
    bytes32 public constant USDT_ASSET_ID =
        0x6ca0cef6107263f3b09a51448617b659278cff744f0e702c24a2f88c91e65a0d;

    bytes32 public constant USDC_ASSET_ID =
        0xf989296bde68043d307a2bc0e59de3445defc5f292eb390b80d78162c8a6b13d;

    bytes32 public constant CNGN_ASSET_ID =
        0x83a18c73cf75a028a24b79cbedb3b8d8ba363b748a3210ddbcaa95eec3b87b3a;

    bytes32 public constant ZARP_ASSET_ID =
        0x12373a3b1c4827c84bf6d7b11df100442695d0abfdb7a20d30a41d67d58e75a8;

    bytes32 public constant BRZ_ASSET_ID =
        0xbc60b55b031dce1ee5679098bf2f35d66a94a566124e2b233324d2bafcc6d5b5;

    bytes32 public constant ETH_ASSET_ID =
        0x8c3fb07cab369fe230ca4e45d095f796c4c1a30131f1799766d4fec5ee1325c0;

    // -------------------------------------------------------------------------
    // Risk Parameters
    // -------------------------------------------------------------------------

    /// @dev Default staleness threshold — 1 hour
    uint256 public constant DEFAULT_MAX_AGE = 3600;

    /// @dev Extended threshold for emerging market stablecoins — 2 hours
    uint256 public constant EMERGING_MAX_AGE = 7200;

    /// @dev Maximum acceptable peg deviation — 5% expressed in basis points
    uint256 public constant MAX_DEVIATION_BPS = 500;

    /// @dev Expected peg value for USD stablecoins scaled to 18 decimals
    int256  public constant EXPECTED_PEG = 1e18;

    // -------------------------------------------------------------------------
    // Protocol State
    // -------------------------------------------------------------------------

    /// @dev Emergency pause — set automatically if oracle health check fails
    bool public paused;

    /// @dev Address authorised to unpause the protocol
    address public guardian;

    // -------------------------------------------------------------------------
    // Price Cache
    // -------------------------------------------------------------------------

    /// @dev Packed struct — price in slot 0, timestamp + decimal share slot 1
    struct CachedPrice {
        int256  price;      // 32 bytes — slot 0
        uint64  cachedAt;   // 8 bytes  ─┐
        int8    decimal;    // 1 byte    ─┘ slot 1 (packed)
    }

    mapping(bytes32 => CachedPrice) private _priceCache;

    /// @dev Cache TTL for non-critical reads — 5 minutes
    uint256 public constant CACHE_TTL = 300;

    // -------------------------------------------------------------------------
    // Per-Asset Staleness Thresholds
    // -------------------------------------------------------------------------

    mapping(bytes32 => uint256) public maxPriceAge;

    // -------------------------------------------------------------------------
    // Events
    // -------------------------------------------------------------------------

    event PriceRead(bytes32 indexed assetId, int256 price, uint256 timestamp);
    event ProtocolPaused(bytes32 indexed assetId, uint256 timestamp);
    event ProtocolUnpaused(address indexed guardian, uint256 timestamp);
    event CacheUpdated(bytes32 indexed assetId, int256 price, uint256 cachedAt);

    // -------------------------------------------------------------------------
    // Errors
    // -------------------------------------------------------------------------

    error AssetNotSupported(bytes32 assetId);
    error PriceFeedStale(bytes32 assetId, uint256 age, uint256 maxAge);
    error PriceDeviationExceeded(bytes32 assetId, int256 price);
    error ProtocolIsPaused();
    error NotGuardian();

    // -------------------------------------------------------------------------
    // Constructor
    // -------------------------------------------------------------------------

    constructor(address _guardian) {
        guardian = _guardian;

        // Configure per-asset staleness thresholds
        maxPriceAge[USDT_ASSET_ID] = DEFAULT_MAX_AGE;
        maxPriceAge[USDC_ASSET_ID] = DEFAULT_MAX_AGE;
        maxPriceAge[CNGN_ASSET_ID] = EMERGING_MAX_AGE;
        maxPriceAge[ZARP_ASSET_ID] = EMERGING_MAX_AGE;
        maxPriceAge[BRZ_ASSET_ID]  = EMERGING_MAX_AGE;
        maxPriceAge[ETH_ASSET_ID]  = DEFAULT_MAX_AGE;
    }

    // -------------------------------------------------------------------------
    // Modifiers
    // -------------------------------------------------------------------------

    /// @dev Reverts if the protocol has been paused due to an oracle failure
    modifier whenNotPaused() {
        if (paused) revert ProtocolIsPaused();
        _;
    }

    /// @dev Pauses the protocol if the given asset's price feed is unhealthy
    modifier whenOracleHealthy(bytes32 assetId) {
        (IIfaPriceFeed.PriceFeed memory info, bool exists) =
            ORACLE.getAssetInfo(assetId);

        if (!exists || !_isFresh(info.lastUpdateTime, maxPriceAge[assetId])) {
            paused = true;
            emit ProtocolPaused(assetId, block.timestamp);
            revert ProtocolIsPaused();
        }
        _;
    }

    // -------------------------------------------------------------------------
    // Core Price Functions
    // -------------------------------------------------------------------------

    /// @notice Fetch and fully verify a single stablecoin price feed.
    ///         Performs existence, staleness, and peg deviation checks.
    /// @param  assetId  The IFÁ Labs bytes32 asset identifier
    /// @return price    Verified scaled price value
    /// @return decimal  Negative scaling exponent (typically -18)
    function getVerifiedPrice(bytes32 assetId)
        public
        view
        returns (int256 price, int8 decimal)
    {
        (IIfaPriceFeed.PriceFeed memory info, bool exists) =
            ORACLE.getAssetInfo(assetId);

        if (!exists)
            revert AssetNotSupported(assetId);

        uint256 age = block.timestamp - info.lastUpdateTime;
        uint256 maxAge = maxPriceAge[assetId] > 0
            ? maxPriceAge[assetId]
            : DEFAULT_MAX_AGE;

        if (!_isFresh(info.lastUpdateTime, maxAge))
            revert PriceFeedStale(assetId, age, maxAge);

        if (!_isReasonable(info.price))
            revert PriceDeviationExceeded(assetId, info.price);

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

    /// @notice Fetch verified prices for multiple assets in a single call.
    ///         More gas-efficient than calling getVerifiedPrice N times.
    /// @param  assetIds  Array of IFÁ Labs bytes32 asset identifiers
    /// @return prices    Array of verified scaled price values
    /// @return decimals  Array of negative scaling exponents
    function getMultipleVerifiedPrices(bytes32[] calldata assetIds)
        external
        view
        returns (int256[] memory prices, int8[] memory decimals)
    {
        (IIfaPriceFeed.PriceFeed[] memory infos, bool[] memory exists) =
            ORACLE.getAssetsInfo(assetIds);

        prices   = new int256[](assetIds.length);
        decimals = new int8[](assetIds.length);

        for (uint256 i = 0; i < assetIds.length; i++) {
            if (!exists[i])
                revert AssetNotSupported(assetIds[i]);

            uint256 maxAge = maxPriceAge[assetIds[i]] > 0
                ? maxPriceAge[assetIds[i]]
                : DEFAULT_MAX_AGE;

            if (!_isFresh(infos[i].lastUpdateTime, maxAge))
                revert PriceFeedStale(
                    assetIds[i],
                    block.timestamp - infos[i].lastUpdateTime,
                    maxAge
                );

            if (!_isReasonable(infos[i].price))
                revert PriceDeviationExceeded(assetIds[i], infos[i].price);

            prices[i]   = infos[i].price;
            decimals[i] = infos[i].decimal;
        }
    }

    /// @notice Get a derived cross-asset price.
    ///         For example: CNGN priced in USDT terms.
    /// @param  assetId0   The asset being priced
    /// @param  assetId1   The denominator asset
    /// @param  direction  Forward or Backward pair direction
    function getCrossAssetPrice(
        bytes32 assetId0,
        bytes32 assetId1,
        IIfaPriceFeed.PairDirection direction
    )
        external
        view
        returns (IIfaPriceFeed.DerivedPair memory pair)
    {
        return ORACLE.getPairbyId(assetId0, assetId1, direction);
    }

    // -------------------------------------------------------------------------
    // Cached Price Read (Non-Critical Paths Only)
    // -------------------------------------------------------------------------

    /// @notice Return a cached price if within TTL, otherwise fetch fresh.
    ///         For use in non-critical read paths only — not for liquidations,
    ///         collateral valuation, or minting.
    /// @param  assetId  The IFÁ Labs bytes32 asset identifier
    function getCachedPrice(bytes32 assetId)
        external
        returns (int256 price, int8 decimal)
    {
        return _getCachedPrice(assetId);
    }

    // -------------------------------------------------------------------------
    // Fallback Price Read
    // -------------------------------------------------------------------------

    /// @notice Attempt to return a verified price. If the primary feed is stale,
    ///         fall back to the cache before reverting.
    ///         Implement secondary oracle logic here for maximum resilience.
    /// @param  assetId  The IFÁ Labs bytes32 asset identifier
    function getVerifiedPriceWithFallback(bytes32 assetId)
        external
        view
        returns (int256 price, int8 decimal, bool fromFallback)
    {
        (IIfaPriceFeed.PriceFeed memory info, bool exists) =
            ORACLE.getAssetInfo(assetId);

        uint256 maxAge = maxPriceAge[assetId] > 0
            ? maxPriceAge[assetId]
            : DEFAULT_MAX_AGE;

        // Primary path — fresh, valid price available
        if (
            exists &&
            _isFresh(info.lastUpdateTime, maxAge) &&
            _isReasonable(info.price)
        ) {
            return (info.price, info.decimal, false);
        }

        // Fallback path — primary stale or invalid
        // Insert secondary oracle call here if available.
        // Example:
        //   (int256 fallbackPrice, bool fallbackFresh) = secondaryOracle.getPrice(assetId);
        //   if (fallbackFresh) return (fallbackPrice, -18, true);

        // If no fallback is available, revert cleanly
        revert PriceFeedStale(
            assetId,
            block.timestamp - info.lastUpdateTime,
            maxAge
        );
    }

    // -------------------------------------------------------------------------
    // Guardian Functions
    // -------------------------------------------------------------------------

    /// @notice Unpause the protocol after an oracle issue has been resolved.
    ///         Only callable by the guardian address.
    function unpause() external {
        if (msg.sender != guardian) revert NotGuardian();
        paused = false;
        emit ProtocolUnpaused(msg.sender, block.timestamp);
    }

    /// @notice Update the staleness threshold for a specific asset.
    ///         Only callable by the guardian address.
    function setMaxPriceAge(bytes32 assetId, uint256 maxAge) external {
        if (msg.sender != guardian) revert NotGuardian();
        maxPriceAge[assetId] = maxAge;
    }

    // -------------------------------------------------------------------------
    // Internal Helpers
    // -------------------------------------------------------------------------

    /// @dev Returns true if the price was updated within the allowed window.
    function _isFresh(uint256 lastUpdateTime, uint256 maxAge)
        internal
        view
        returns (bool)
    {
        return block.timestamp - lastUpdateTime <= maxAge;
    }

    /// @dev Returns true if the price is within ±MAX_DEVIATION_BPS of the peg.
    ///      Only applies to USD stablecoins. Do not use for ETH or volatile assets.
    function _isReasonable(int256 price)
        internal
        pure
        returns (bool)
    {
        int256 deviation = price - EXPECTED_PEG;
        if (deviation < 0) deviation = -deviation;
        return uint256(deviation) <= uint256(EXPECTED_PEG) * MAX_DEVIATION_BPS / 10000;
    }

    /// @dev Fetch from cache if within TTL, otherwise read from oracle and
    ///      update cache. Writes to storage — not a view function.
    function _getCachedPrice(bytes32 assetId)
        internal
        returns (int256 price, int8 decimal)
    {
        CachedPrice storage cached = _priceCache[assetId];

        if (
            cached.cachedAt > 0 &&
            block.timestamp - cached.cachedAt <= CACHE_TTL
        ) {
            return (cached.price, cached.decimal);
        }

        // Cache miss — fetch fresh from oracle
        (IIfaPriceFeed.PriceFeed memory info, bool exists) =
            ORACLE.getAssetInfo(assetId);

        if (!exists) revert AssetNotSupported(assetId);

        _priceCache[assetId] = CachedPrice({
            price:    info.price,
            cachedAt: uint64(block.timestamp),
            decimal:  info.decimal
        });

        emit CacheUpdated(assetId, info.price, block.timestamp);

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

Adapting This Contract

This reference implementation is intentionally complete. When adapting it for your protocol, consider the following: Remove what you don’t need. Not every protocol needs a cache, a guardian, and fallback logic simultaneously. Start from this reference and strip out the patterns that don’t apply to your use case. A simpler contract with fewer moving parts is always preferable if it meets your requirements. Review all constants for your risk profile. DEFAULT_MAX_AGE, EMERGING_MAX_AGE, MAX_DEVIATION_BPS, and CACHE_TTL are starting points, not universal values. Set them based on your protocol’s actual risk tolerance and the observed update cadence of the assets you’re consuming. Replace the guardian pattern with your governance system. The single-address guardian is the simplest possible access control pattern. Production protocols typically use a timelock, multisig, or full governance contract for parameter updates. Swap guardian for whatever access control model your protocol already uses. Implement secondary oracle logic in getVerifiedPriceWithFallback. The fallback function has a clearly marked placeholder for a secondary oracle call. If your protocol requires maximum uptime, integrate a secondary source — Chainlink, Pyth, or a TWAP — at that point. Add your protocol logic. This contract has no deposit, borrow, swap, or settlement logic — those are yours to build on top of these price reading foundations.

Deployment Checklist

Before deploying to mainnet:

Verify oracle address

Confirm 0xA9F17344689C2c2328F94464998db1d3e35B80dC against the Contract Addresses reference page and Basescan.

Verify all asset IDs

Hash each symbol string independently and compare against the Supported Assets table. Run the Foundry test pattern from Working with Asset IDs.

Review risk parameters

Confirm DEFAULT_MAX_AGE, EMERGING_MAX_AGE, MAX_DEVIATION_BPS, and CACHE_TTL are appropriate for your protocol’s risk tolerance.

Replace guardian address

Set the guardian constructor argument to your protocol’s multisig or governance contract — not a development wallet.

Run a full test suite

Test all price read paths including stale prices, missing assets, deviation breaches, and cache TTL expiry. Use Foundry’s vm.warp to simulate time-based scenarios.

Benchmark gas costs

Run Foundry’s gas reporter against your adapted contract under realistic conditions before committing to the architecture.

Deploy to Base Sepolia first

Test against the live testnet oracle — not just mocks — before mainnet deployment.

INTRODUCTION

QUICKSTART

INTEGRATION GUIDES

CORE CONCEPTS

ONCHAIN REFERENCE

SECURITY & AUDITS

ADVANCED TOPICS

TROUBLESHOOTING

REFERENCE

SUPPORT & COMMUNITY

What This Contract Demonstrates

The Contract

Adapting This Contract

Deployment Checklist

Next Steps

Core Concepts

MCP Server

​What This Contract Demonstrates

​The Contract

​Adapting This Contract

​Deployment Checklist

​Next Steps

Core Concepts

MCP Server

What This Contract Demonstrates

The Contract

Adapting This Contract

Deployment Checklist

Next Steps