Event Reference

The IFÁ Labs oracle contract emits events on every successful price update. These events are the foundation of any off-chain infrastructure built on top of IFÁ Labs — monitoring systems, subgraphs, alert pipelines, analytics dashboards, and historical price databases all depend on them. This page documents every event, its parameters, and how to consume it correctly in JavaScript, Python, and via on-chain indexing tools.

Events

`PriceUpdated`

Emitted every time a price is successfully pushed on-chain by the relayer network.

event PriceUpdated(
    bytes32 indexed assetId,
    int256          price,
    int8            decimal,
    uint64          timestamp
);

Parameters:

Parameter	Type	Indexed	Description
`assetId`	`bytes32`	Yes	The asset identifier — `keccak256(abi.encodePacked("SYMBOL/USD"))`. Indexed for efficient log filtering.
`price`	`int256`	No	The new scaled price value stored on-chain.
`decimal`	`int8`	No	Negative scaling exponent — typically `-18` for all current feeds.
`timestamp`	`uint64`	No	The block timestamp at the time of submission. Matches `lastUpdateTime` returned by `getAssetInfo`.

When it fires:

On every successful deviation-triggered update
On every successful heartbeat-triggered update
Never fires on failed or rejected submissions

Key properties:

assetId is indexed — you can filter logs for a specific asset without downloading all events
timestamp matches the lastUpdateTime field returned by getAssetInfo — the two values are always in sync
One event is emitted per asset per update — batch submissions emit one event per asset

Listening to Events

JavaScript — Real-Time with ethers.js

Listen for live price updates as they happen on-chain:

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

const ORACLE_ADDRESS = "0xA9F17344689C2c2328F94464998db1d3e35B80dC";
const RPC_WSS = "wss://base-mainnet.g.alchemy.com/v2/YOUR_API_KEY";

const ABI = [
  "event PriceUpdated(bytes32 indexed assetId, int256 price, int8 decimal, uint64 timestamp)"
];

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

// Asset IDs to monitor
const WATCHED_ASSETS = {
  "0x6ca0cef6107263f3b09a51448617b659278cff744f0e702c24a2f88c91e65a0d": "USDT/USD",
  "0xf989296bde68043d307a2bc0e59de3445defc5f292eb390b80d78162c8a6b13d": "USDC/USD",
  "0x83a18c73cf75a028a24b79cbedb3b8d8ba363b748a3210ddbcaa95eec3b87b3a": "CNGN/USD",
  "0x12373a3b1c4827c84bf6d7b11df100442695d0abfdb7a20d30a41d67d58e75a8": "ZARP/USD",
  "0xbc60b55b031dce1ee5679098bf2f35d66a94a566124e2b233324d2bafcc6d5b5": "BRZ/USD",
  "0x8c3fb07cab369fe230ca4e45d095f796c4c1a30131f1799766d4fec5ee1325c0": "ETH/USD",
};

oracle.on("PriceUpdated", (assetId, price, decimal, timestamp, event) => {
  const symbol     = WATCHED_ASSETS[assetId] ?? `Unknown (${assetId.slice(0, 10)}...)`;
  const exponent   = -Number(decimal);
  const humanPrice = (Number(price) / 10 ** exponent).toFixed(6);
  const updatedAt  = new Date(Number(timestamp) * 1000).toISOString();

  console.log(`[${updatedAt}] ${symbol}: $${humanPrice}`);
  console.log(`  tx: ${event.log.transactionHash}`);
});

console.log("Listening for IFÁ Labs price updates on Base Mainnet...");

WebSocket connections are required for real-time event listening. HTTP RPC providers do not support eth_subscribe. Use a dedicated WebSocket provider — Alchemy, QuickNode, or Infura — not the public Base RPC endpoint.

JavaScript — Historical Query with ethers.js

Query past price update events for a specific asset over a block range:

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

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

const ABI = [
  "event PriceUpdated(bytes32 indexed assetId, int256 price, int8 decimal, uint64 timestamp)"
];

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

const CNGN_ASSET_ID =
  "0x83a18c73cf75a028a24b79cbedb3b8d8ba363b748a3210ddbcaa95eec3b87b3a";

async function getPriceHistory(assetId, lookbackBlocks = 50000) {
  const currentBlock = await provider.getBlockNumber();
  const fromBlock    = currentBlock - lookbackBlocks;

  console.log(`Fetching CNGN/USD history from block ${fromBlock} to ${currentBlock}...`);

  const events = await oracle.queryFilter(
    oracle.filters.PriceUpdated(assetId),
    fromBlock,
    currentBlock
  );

  const history = events.map(event => ({
    blockNumber:  event.blockNumber,
    txHash:       event.transactionHash,
    price:        (Number(event.args.price) / 1e18).toFixed(6),
    timestamp:    new Date(Number(event.args.timestamp) * 1000).toISOString(),
  }));

  console.log(`Found ${history.length} updates:`);
  history.forEach(h => {
    console.log(`  Block ${h.blockNumber} | ${h.timestamp} | $${h.price}`);
  });

  return history;
}

getPriceHistory(CNGN_ASSET_ID);

Python — Real-Time with web3.py

from web3 import Web3
from web3.middleware import ExtraDataToPOAMiddleware
import json
import time

RPC_WSS       = "wss://base-mainnet.g.alchemy.com/v2/YOUR_API_KEY"
ORACLE_ADDRESS = "0xA9F17344689C2c2328F94464998db1d3e35B80dC"

ABI = json.loads('[{"anonymous":false,"inputs":[{"indexed":true,"name":"assetId","type":"bytes32"},{"indexed":false,"name":"price","type":"int256"},{"indexed":false,"name":"decimal","type":"int8"},{"indexed":false,"name":"timestamp","type":"uint64"}],"name":"PriceUpdated","type":"event"}]')

ASSET_SYMBOLS = {
    "0x6ca0cef6107263f3b09a51448617b659278cff744f0e702c24a2f88c91e65a0d": "USDT/USD",
    "0x83a18c73cf75a028a24b79cbedb3b8d8ba363b748a3210ddbcaa95eec3b87b3a": "CNGN/USD",
    "0x12373a3b1c4827c84bf6d7b11df100442695d0abfdb7a20d30a41d67d58e75a8": "ZARP/USD",
}

w3     = Web3(Web3.WebsocketProvider(RPC_WSS))
oracle = w3.eth.contract(address=ORACLE_ADDRESS, abi=ABI)

def handle_price_update(event):
    asset_id    = event["args"]["assetId"].hex()
    price       = event["args"]["price"]
    decimal     = event["args"]["decimal"]
    timestamp   = event["args"]["timestamp"]
    symbol      = ASSET_SYMBOLS.get(f"0x{asset_id}", f"Unknown ({asset_id[:10]}...)")
    human_price = price / (10 ** -decimal)

    print(f"[{symbol}] ${human_price:.6f} at {timestamp}")

event_filter = oracle.events.PriceUpdated.create_filter(from_block="latest")

print("Listening for IFÁ Labs price updates...")
while True:
    for event in event_filter.get_new_entries():
        handle_price_update(event)
    time.sleep(2)

Basescan — Manual Event Inspection

To inspect price update events without writing code:

Open the Events tab

Go to the contract on Basescan and click the Events tab: basescan.org/address/0xA9F17344689C2c2328F94464998db1d3e35B80dC#events

Filter by asset ID

Use the topic filter to narrow results to a specific asset. The assetId parameter is indexed — enter the bytes32 value for the asset you want to inspect as Topic 1.

Read the event data

Each row shows the transaction hash, block number, and decoded event parameters — price, decimal, and timestamp. The price field is the raw scaled integer — divide by 1e18 for the human-readable value.

Building a Price History Database

For analytics dashboards, historical price charts, or audit trails, persist PriceUpdated events to a database as they arrive:

const { ethers } = require("ethers");
const { Pool }   = require("pg"); // PostgreSQL client

const db = new Pool({ connectionString: process.env.DATABASE_URL });

// Create table if not exists
await db.query(`
  CREATE TABLE IF NOT EXISTS price_updates (
    id           SERIAL PRIMARY KEY,
    asset_id     TEXT        NOT NULL,
    symbol       TEXT,
    price        NUMERIC     NOT NULL,
    raw_price    TEXT        NOT NULL,
    decimal      INTEGER     NOT NULL,
    block_number BIGINT      NOT NULL,
    tx_hash      TEXT        NOT NULL,
    updated_at   TIMESTAMPTZ NOT NULL,
    created_at   TIMESTAMPTZ DEFAULT NOW()
  );

  CREATE INDEX IF NOT EXISTS idx_price_updates_asset_id
    ON price_updates(asset_id);

  CREATE INDEX IF NOT EXISTS idx_price_updates_updated_at
    ON price_updates(updated_at DESC);
`);

const ASSET_SYMBOLS = {
  "0x6ca0cef6107263f3b09a51448617b659278cff744f0e702c24a2f88c91e65a0d": "USDT/USD",
  "0xf989296bde68043d307a2bc0e59de3445defc5f292eb390b80d78162c8a6b13d": "USDC/USD",
  "0x83a18c73cf75a028a24b79cbedb3b8d8ba363b748a3210ddbcaa95eec3b87b3a": "CNGN/USD",
  "0x12373a3b1c4827c84bf6d7b11df100442695d0abfdb7a20d30a41d67d58e75a8": "ZARP/USD",
  "0xbc60b55b031dce1ee5679098bf2f35d66a94a566124e2b233324d2bafcc6d5b5": "BRZ/USD",
  "0x8c3fb07cab369fe230ca4e45d095f796c4c1a30131f1799766d4fec5ee1325c0": "ETH/USD",
};

oracle.on("PriceUpdated", async (assetId, price, decimal, timestamp, event) => {
  const exponent   = -Number(decimal);
  const humanPrice = Number(price) / 10 ** exponent;

  await db.query(
    `INSERT INTO price_updates
      (asset_id, symbol, price, raw_price, decimal, block_number, tx_hash, updated_at)
     VALUES ($1, $2, $3, $4, $5, $6, $7, to_timestamp($8))`,
    [
      assetId,
      ASSET_SYMBOLS[assetId] ?? null,
      humanPrice,
      price.toString(),
      Number(decimal),
      event.log.blockNumber,
      event.log.transactionHash,
      Number(timestamp),
    ]
  );

  console.log(`Persisted: ${ASSET_SYMBOLS[assetId]} = $${humanPrice.toFixed(6)}`);
});

Indexing with The Graph

For production-grade historical data access, index PriceUpdated events using The Graph:

// schema.graphql
type PriceUpdate @entity {
  id:          ID!
  assetId:     Bytes!
  symbol:      String
  price:       BigInt!
  decimal:     Int!
  humanPrice:  BigDecimal!
  timestamp:   BigInt!
  blockNumber: BigInt!
  txHash:      Bytes!
}

// mapping.ts
import { PriceUpdated } from "../generated/IfaPriceFeed/IfaPriceFeed";
import { PriceUpdate }  from "../generated/schema";
import { BigDecimal, BigInt } from "@graphprotocol/graph-ts";

const ASSET_SYMBOLS = new Map<string, string>();
ASSET_SYMBOLS.set(
  "0x6ca0cef6107263f3b09a51448617b659278cff744f0e702c24a2f88c91e65a0d",
  "USDT/USD"
);
ASSET_SYMBOLS.set(
  "0x83a18c73cf75a028a24b79cbedb3b8d8ba363b748a3210ddbcaa95eec3b87b3a",
  "CNGN/USD"
);
ASSET_SYMBOLS.set(
  "0x12373a3b1c4827c84bf6d7b11df100442695d0abfdb7a20d30a41d67d58e75a8",
  "ZARP/USD"
);

export function handlePriceUpdated(event: PriceUpdated): void {
  const id     = event.transaction.hash.toHex() + "-" + event.logIndex.toString();
  const update = new PriceUpdate(id);

  const exponent  = BigInt.fromI32(-event.params.decimal);
  const divisor   = BigInt.fromI32(10).pow(exponent.toI32() as u8);
  const humanPrice = new BigDecimal(event.params.price).div(
    new BigDecimal(divisor)
  );

  update.assetId     = event.params.assetId;
  update.symbol      = ASSET_SYMBOLS.has(event.params.assetId.toHex())
                         ? ASSET_SYMBOLS.get(event.params.assetId.toHex())
                         : null;
  update.price       = event.params.price;
  update.decimal     = event.params.decimal;
  update.humanPrice  = humanPrice;
  update.timestamp   = event.params.timestamp;
  update.blockNumber = event.block.number;
  update.txHash      = event.transaction.hash;

  update.save();
}

Event Monitoring Best Practices

Use WebSockets for real-time feeds, HTTP for historical queries. WebSocket providers support eth_subscribe for live event streaming. HTTP providers require polling with queryFilter — adequate for historical data but not for real-time monitoring. Store raw values alongside human-readable values. Always persist both raw_price (the unscaled int256) and the human-readable price in your database. The raw value is lossless — the human-readable conversion may lose precision depending on your numeric type. If you ever need to reprocess historical data, the raw value is the authoritative source. Index by assetId and updated_at. These are the two axes on which you will query price history — “all updates for CNGN/USD” and “all updates in the last 24 hours.” Both should be indexed in your database for acceptable query performance at scale. Handle WebSocket reconnections. WebSocket connections to RPC providers drop periodically. Any production event listener must implement reconnection logic — either manually or through a library that handles it automatically. Backfill from genesis block on first deployment. When deploying a price history database for the first time, backfill all historical PriceUpdated events from the oracle contract’s deployment block before switching to live streaming. Otherwise your historical data will have a gap.

Next Steps

ABI Download

Get the official ABI for use in your monitoring scripts and indexers.

Running Price Monitoring

Production-ready monitoring scripts built on the event patterns documented here.

INTRODUCTION

QUICKSTART

INTEGRATION GUIDES

CORE CONCEPTS

ONCHAIN REFERENCE

SECURITY & AUDITS

ADVANCED TOPICS

TROUBLESHOOTING

REFERENCE

SUPPORT & COMMUNITY

Events

`PriceUpdated`

Listening to Events

JavaScript — Real-Time with ethers.js

JavaScript — Historical Query with ethers.js

Python — Real-Time with web3.py

Basescan — Manual Event Inspection

Building a Price History Database

Indexing with The Graph

Event Monitoring Best Practices

Next Steps

ABI Download

Running Price Monitoring

​Events

​PriceUpdated

​Listening to Events

​JavaScript — Real-Time with ethers.js

​JavaScript — Historical Query with ethers.js

​Python — Real-Time with web3.py

​Basescan — Manual Event Inspection

​Building a Price History Database

​Indexing with The Graph

​Event Monitoring Best Practices

​Next Steps

ABI Download

Running Price Monitoring

Events

`PriceUpdated`

Listening to Events

JavaScript — Real-Time with ethers.js

JavaScript — Historical Query with ethers.js

Python — Real-Time with web3.py

Basescan — Manual Event Inspection

Building a Price History Database

Indexing with The Graph

Event Monitoring Best Practices

Next Steps