This is GitHub's original announcement of their public GraphQL API, which also explains some of the reasons they chose to use it.
Read this page in the docs of Shopify's public GraphQL API about why it wins over REST for their use cases.
Read about all the ways that GraphQL improved the page load speeds at Artsy by reducing payload sizes and number of requests.
Walmart released its own production-grade Clojure GraphQL implementation, and this blog post explains why GraphQL made sense for them.
In mid-2017, Yelp became one of the most notable companies to release a public GraphQL API, read the introduction and how to use it.
Read one of the first blog posts about GraphQL from Facebook, where Lee Byron talks about how it was a crucial part of Facebook's native mobile app push in 2012.
How Coursera enabled 1,000s of REST APIs across microservices to work with GraphQL, automatically.
Read how the new New York Times website uses GraphQL, easily binding data to React components with Relay.
This article describes the usage of GraphQL at Circle, the payment company. It describes how GraphQL solved their challenges and how they designed their payment schema and resolvers.
Why Astronomer implemented their newest feature and public API with GraphQL: Reducing requests, joining data across sources, and easy-to-use documentation.