Today’s crypto landscape can be daunting. As exchanges and tokens proliferate, keeping up with market data becomes a Sisyphean task.

The following sections give a simple guide to building an API that provides price feed data to your crypto-enabled application.

Nomics and Market Data

Accurately knowing the market price at any given time requires pulling from potentially dozens of exchange API’s and doing a few clever calculations.

Luckily, there is already a free service that has done the legwork for you.

Meet Nomics, the crypto market data API trusted here at TokenSoft. So much so in fact, we became an investor in 2018.

Nomics keeps prices extremely up-to-date, re-calculating every 10 seconds and weighting 24 hour volumes across leading exchanges. For the extra curious, check out an in-depth explanation of Nomic’s pricing methodology.

Here’s what we’ll cover

1- Setting up the GraphQL server with Node.js and NPM

2- Obtaining a free Nomics API key

3- Pulling (USD) price data from the Nomics API and caching the results

4- Exposing a GraphQL endpoint to query price data

Prerequisites

You should have Node.js and NPM installed on your machine. General JavaScript experience is assumed.

Full source code for this example can be referenced here.

1. Setting Up the GraphQL Server





2. Obtaining a Free Nomics API Key

Head on over to Nomics’ pricing page and select their free tier.


Fill out and submit the registration form.


You should receive an email with your API key shortly!


3. Pulling Price Data From the Nomics API





Final Thoughts

If you’ve made it this far, congratulations!

We’ve covered setting up a GraphQL server with a cached exchange rate endpoint.

Next steps could include supporting fiat pairs other than USD. Additionally, Nomics’ dashboard endpoint is a great place to expand your API to support metrics such as 24-hour volume or price movement. All source code for the above example can be found here.

If you are interested in working with or at TokenSoft Inc, feel free to reach out.