Over the last few years, GraphQL has emerged as a very popular API specification that focuses on making data fetching easier for clients, whether the clients are a front-end or a third-party.

In a traditional REST-based API approach, the client makes a request, and the server dictates the response:

$ curl https://api.heroku.space/users/1 { "id": 1, "name": "Luke", "email": "luke@heroku.space", "addresses": [ { "street": "1234 Rodeo Drive", "city": "Los Angeles", "country": "USA" } ] } 

But, in GraphQL, the client determines precisely the data it wants from the server....

If your application is successful, there may come a time where you’re on an unsupported version of a dependency. In the case of the Heroku Platform API, this dependency was a very old version of Active Record from many years ago. Due to the complexity involved in the upgrade, this core piece of infrastructure had been pegged at version 2.3.18, which was released in March 2013. We're happy to announce that we've overcome the challenge and are now running Active Record 4.2.4, the latest version, in production. In this post, we'll describe the technical challenges we faced in the upgrade process and take a look at how your organization could benefit from upgrading legacy software...