@pulsadev/price-feed

Chainlink oracle price feed reader — real-time token prices, batch queries, built-in feed registry. Zero dependencies, pure RPC.

Read live token prices directly from Chainlink oracles. No API key, no CoinGecko, no rate limits. Just an RPC URL.

Features

• Real-time prices — read latestRoundData() from Chainlink aggregators
• Batch price queries — fetch ETH, BTC, LINK prices in parallel
• Built-in feed registry — 50+ Chainlink feed addresses across 7 chains
• Historical prices — getRoundData(roundId) for past price data
• Staleness detection — check if price data is stale based on heartbeat
• Feed metadata — query decimals and description from feed contracts
• Price formatting — raw answer to human-readable price conversion
• 7 chains — Ethereum, Polygon, Arbitrum, BSC, Avalanche, Optimism, Base
• Zero dependencies — ~9 KB bundled, ESM + CJS, pure TypeScript

Install

npm install @pulsadev/price-feed

Quick Start

Get a price

import { getPriceByPair } from '@pulsadev/price-feed'

const eth = await getPriceByPair('ETH/USD', {
  rpcUrl: 'https://ethereum-rpc.publicnode.com',
})

console.log(`ETH: $${eth.price}`)       // ETH: $2534.12
console.log(`Updated: ${eth.updatedAt}`) // Unix timestamp
console.log(`Stale: ${eth.stale}`)       // false

Batch prices

import { getPrices } from '@pulsadev/price-feed'

const prices = await getPrices(['ETH/USD', 'BTC/USD', 'LINK/USD'], {
  rpcUrl: 'https://ethereum-rpc.publicnode.com',
  chainId: 1,
})

prices.forEach(p => console.log(`${p.pair}: $${p.price}`))

All prices for a chain

import { getAllPrices } from '@pulsadev/price-feed'

const all = await getAllPrices({ rpcUrl: '...', chainId: 1 })
// Returns 20+ prices for all registered Ethereum feeds

Direct feed address

import { getPrice } from '@pulsadev/price-feed'

const data = await getPrice('0x5f4eC3Df9cbd43714FE2740f5E3616155c5b8419', {
  rpcUrl: '...',
})

Historical price

import { getHistoricalPrice } from '@pulsadev/price-feed'

const past = await getHistoricalPrice(feedAddress, roundId, { rpcUrl: '...' })

Staleness check

import { isStale } from '@pulsadev/price-feed'

if (isStale(priceData.updatedAt, 3600)) {
  console.log('Price is stale!')
}

Browse available feeds

import { getSupportedPairs, getFeedByPair, getSupportedChainIds } from '@pulsadev/price-feed'

getSupportedChainIds()        // [1, 56, 137, 42161, 43114, 10, 8453]
getSupportedPairs(1)          // ['ETH/USD', 'BTC/USD', 'LINK/USD', ...]
getFeedByPair(1, 'ETH/USD')   // { address, decimals, heartbeatSeconds }

API

Price Reading

| Function | Description | |----------|-------------| | getPrice(feedAddress, options) | Read latest price from feed | | getPriceByPair(pair, options) | Read price by pair name (e.g. 'ETH/USD') | | getPrices(pairs, options) | Batch read multiple pairs | | getAllPrices(options) | Read all registered feeds for a chain | | getHistoricalPrice(feed, roundId, options) | Read historical round data |

Feed Registry

| Function | Description | |----------|-------------| | getFeedByPair(chainId, pair) | Get feed config by pair name | | getFeedsByChain(chainId) | Get all feeds for a chain | | getSupportedPairs(chainId) | List available pairs | | getSupportedChainIds() | List supported chains |

Utilities

| Function | Description | |----------|-------------| | getFeedDecimals(feed, rpcUrl) | Query feed decimals | | getFeedDescription(feed, rpcUrl) | Query feed description | | isStale(updatedAt, threshold) | Check price staleness | | formatPrice(rawAnswer, decimals) | Convert raw to human-readable |

PriceData

interface PriceData {
  pair: string           // 'ETH/USD'
  price: number          // 2534.12
  decimals: number       // 8
  rawAnswer: bigint      // 253412000000n
  roundId: bigint        // round ID
  updatedAt: number      // Unix timestamp
  answeredInRound: bigint
  feed: Address          // feed contract address
  stale: boolean         // true if data exceeds heartbeat
}

Supported Chains

| Chain | Feeds | |-------|-------| | Ethereum (1) | 20 (ETH, BTC, LINK, USDC, USDT, DAI, UNI, AAVE, SOL, ARB, OP, ...) | | Polygon (137) | 5 | | Arbitrum (42161) | 5 | | BSC (56) | 4 | | Avalanche (43114) | 3 | | Optimism (10) | 4 | | Base (8453) | 2 |

License

MIT © Yuto Nakamura