Can you explain the differences between REST and GraphQL APIs, and when you might prefer one over the other?

In my final year project, I developed a web application that allowed users to track their reading habits. I initially used a REST API to fetch data about books and authors. It was straightforward to set up with standard endpoints. However, as I added features, like tracking reading progress and adding reviews, I realized REST's rigid structure made it challenging to get all the necessary data with fewer requests. If I had used GraphQL, I could have designed queries to pull specific information in a single request, which would have streamlined the user experience and reduced load times. This experience taught me the importance of choosing the right API architecture based on project needs.

While volunteering for a local charity, I helped create a system to manage event registrations. We originally planned to use a REST API to handle the registrations, ticketing, and attendee information. However, the requirements changed, and we needed to include various user types and multiple events. I suggested using GraphQL, which allowed us to define flexible queries that could accommodate the diverse data needs of our users. This adaptability made it easier for the team to iterate on our design without restructuring the entire API, showing how GraphQL can be beneficial in dynamic environments.

In my first job at a tech startup, I was part of a team that developed a mobile application. We used REST APIs for the initial version due to its simplicity. However, as we scaled and added features, we faced challenges with multiple endpoints and data fetching inefficiencies. Transitioning to GraphQL allowed our developers to optimize data retrieval and reduce over-fetching, significantly improving app performance. This experience highlighted the importance of evolving our API strategy in response to user feedback and product growth, reinforcing my understanding of when to apply REST versus GraphQL in real-world applications.