Over a few years back, REST APIs were considered standard web APIs, which nowhave a strong competitor. REST APIs provide some excellent features like stateless serversand structured access to resources. However, over time, it doesn’t offer flexibility withthe access of data and client changing requirements. In 2015 GraphQL was introduced byFacebook, which overcomes the problems with the REST and provides more flexibility andefficiency to the client requirements. For example, remove the over and under fetching.To change the existing APIs into GraphQL APIs require considerable time and effort.Therefore, some server implementation tools are developed to reduce the developmentcost and time. A few of these tools generate GraphQL schema and server implementationsautomatically over a legacy database.This master thesis studies tools that automatically generate GraphQL server implementationover legacy databases and evaluate such generated GraphQL server’s performance.First, we find some GraphQL server implementation tools such as Hasura andPostGraphile and then compare the server’s performance using benchmark methodology.Secondly, we run an experiment on a computer system and use the performance metricsfor assessment. The results of our experiment concluded that PostGraphile has higherthroughput and low query execution time as compared to Hasura. In most of the querytemplates from the benchmark, PostGraphile outperforms Hasura.