Limestone API

Limestone API is a Javascript library for fetching trusted token pricing data from Limestone data ecosystem.

It is a Javascript wrapper for Limestone HTTP Api.

✅ Why Limestone API

✓ Secure

Limestone pricing data is secured on Arweave and protected by the provider's collateral. Learn more

✓ Easy to use

You don't need any API keys. Just install the npm package and add a single line of code. Quick start

✓ 150+ tokens

We support BTC, ETH, AR, EUR, and many other crypto and fiat currencies. All supported tokens

✓ TypeScript Support

Limestone API is fully written in Typescript and then compiled to JavaScript. Source code

📦 Installation

Using npm

npm install limestone-api

Using yarn

yarn add limestone-api

🤖 Usage

Importing

// Using Node.js `require()`
const limestone = require('limestone-api');

// Using ES6 imports
import limestone from 'limestone-api';

Get the latest price for a single token

const price = await limestone.getPrice("AR");

console.log(price.value); // latest price value for AR token (in USD)
console.log(price.timestamp); // the exact timestamp of the price

💡 Note: All the prices are denominated in USD. You can fetch price data for BTC, ETH, AR, EUR and any other of 158 supported tokens.

{
  value: 123.23, // Number: Price value in USD
  timestamp: 1617146511173, // Number: Timestamp (ms) for price
  provider: "I-5rWUehEv-MjdK9gFw09RxfSLQX9DIHxG614Wf8qo0", // String: Provider arweave address
  permawebTx: "V8FUU0BG4kVOJwKWHzgkn1aEFm-eanhqqEXfPFY7pmI", // String: Arweave transaction id
  source: {"coingecko": 123,"sushiswap": 123.23,"uniswap": 123.35}, // Object: Prices from different sources
}

// As async/await is only a syntactic sugar on Javascript
// Promises you can use them in a "standard" way
const price = limestone.getPrice("AR").then((price) => {
  console.log(price.value); // latest price value for AR token
});

Get the latest prices for several tokens

To fetch prices for several tokens use the getPrice method and pass an array with any subset of supported tokens.

const prices = await limestone.getPrice(["BTC", "ETH", "AR", "EUR"]);

console.log(prices); // Example output below
/*
{
  "BTC": {
    value: 58953.39,
    timestamp: 1617152802779,
    ...
  },
  "ETH": {
    value: 1856.75,
    timestamp: 1617152802779,
    ...
  },
  ...
}
*/


console.log(prices["BTC"].value); // latest price value for BTC
console.log(prices["ETH"].value); // latest price value for ETH
console.log(prices["AR"].value); // latest price value for AR

Get prices for all available tokens

To fetch the latest prices for all available tokens use the getAllPrices method.

const prices = await limestone.getAllPrices();

console.log(prices); // Example output below
/*
{
  "BTC": {...},
  "ETH": {...},
  ...
}
*/

console.log(prices["AR"].value); // latest price value for AR
console.log(prices["EUR"].value); // latest price value for EUR
console.log(Object.keys(prices).length); // 158

Get the historical price for a single token

To get the historical price use the getHistoricalPrice method.

const price = await limestone.getHistoricalPrice("AR", {
  date: "2021-03-30T12:35:09", // Any convertable to date type
});

console.log(price.value); // AR price for specific time

💡 Note: date argument must be convertable to Date type. You may pass date (e.g. new Date(2021-04-01)), timestamp (e.g. 1617709771289), or just string (e.g. 2021-04-01 or 2021-04-01T12:30:58).

Get the historical price for several tokens

To fetch the historical price for several tokens pass an array of symbols to getHistoricalPrice method.

const symbols = ["AR", "BTC", "UNI", "ETH", "EUR"];
const prices = await limestone.getHistoricalPrice(symbols, {
  date: "2021-03-30T12:35:09",
});

console.log(prices["BTC"].value); // BTC price for specific time

Get the historical prices in a time range

To fetch the historical prices in a time range specify token symbol as the first argument of the getHistoricalPrice method, and startDate, endDate and interval as fields of the second argument.

💡 Note: currently Limestone API supports fetching historical prices in a time range only for a single token.

const prices = await limestone.getHistoricalPrice("AR", {
  startDate: "2021-03-29T12:35:09",
  endDate: "2021-03-30T12:35:09",
  interval: 3600 * 1000, // 1 hour
});

console.log(prices); // Example output below
/*
[
  {
    value: 28.8,
    timestamp: 1617016995624,
    ...
  },
  {
    value: 28.59,
    timestamp: 1617014111705,
    ...
  },
  ...
]
*/

💡 Note: startDate and endDate argument must be convertable to Date type.

Verify signature

All prices saved in Limestone have a signature, thanks to which you always can verify if the price data has been submitted by the trusted provider.

To do so you can set verifySignature option to true in getPrice, getHistoricalPrice or getAllPrices methods. If signature is invalid - error will be thrown.

const price = await limestone.getPrice("AR", {
  verifySignature: true,
});
console.log(price.value);

Get prices from Arweave

By default, Limestone API fetches data from the Limestone cache layer. It works way faster than fetching directly from Arweave Blockchain. Even so, thanks to signature verification prices data is still trusted and secure.

We strongly recommend using the default fetching mechanism. But if you want to fetch data directly from Arweave you can do it by initialising a new LimestoneApi client and setting useCache option to false.

const LimestoneApi = require("limestone-api/lib/limestone-api");

const limestoneArweaveClient = LimestoneApi.default.init({
  useCache: false,
});

const price = await limestoneArweaveClient.getPrice("AR");

console.log(price.value); // AR price value fetched directly from Arweave

📅 Roadmap

Fluent Interface

We currently work on a fluent interface to make Limestone API even easier to use. You can see examples of fluent interface usage and let us know what you think (we would be very grateful 😉).

🚀 Examples

• Discord bot
• Web app

💬 Contributing

Pull requests are welcome. For major changes, please open an issue first to discuss what you would like to change.

Please make sure to update tests as appropriate.

📜 License

This software is licensed under the MIT © Limestone