The authors of the article, who work on the @neo4j/graphql library, were facing performance issues with their Node.js GraphQL server. To identify and fix these problems, they used a combination of tools and techniques, including measuring the performance of their server, load testing with K6, and using Clinic.js to analyze their code's performance. They found that the main bottleneck was not in the database or the library itself, but rather in the JavaScript code processing the GraphQL queries. By optimizing this code and using a more efficient GraphQL parser, such as Yoga instead of Apollo, they were able to significantly improve the server's performance. The article provides a detailed example of how these improvements can be made and offers practical advice for developers who want to optimize their own Node.js GraphQL servers.