The Community plan of Apollo Engine offers schema registry and explorer tools. You can find them by clicking on the Explorer tab in the left-hand panel. If your setup has gone well, the page should look as follows:

Let's take a closer look at this screenshot:

• On the page, you see the last GraphQL schema that you have published. Each schema you publish has a unique version, as long as the schema includes changes.

• Beneath the version number, you can see your entire GraphQL schema. You can inspect all operations and types. All relations between types and operations are directly linked to each other.
• You can directly see the number of clients and various usage statistics next to each operation, type, and field.
• You can search through your GraphQL schema in the top bar and filter the usage statistics in the panel on the right.

You can also switch to the Deprecation tab at the top. This page gives you a list of fields that are deprecated. We won't use this page because we are using the latest field definitions, but it's vital if you're running an application for a longer time.

Having an overview of our schema is beneficial. In production, every new release of our application is likely to also bring changes to the GraphQL schema. With Apollo Engine, you can track those changes easily. This feature is called schema-change validation and is only included in the paid Team plan of Apollo Engine. It's worth the extra money because it allows you to track schema changes and also to compare how those fields are used. It allows us to draw conclusions about which clients and versions are being used at the moment.

I have created an example for you in the following screenshot:

Here, I published an initial version of our current GraphQL schema. Afterward, I added a demonstration type with one field, called example. On the right-hand side, you can see the schema difference between the initial and second releases of the GraphQL schema.

Viewing your schema inside Apollo Engine, including the history of all previous schemas, is very useful. In the next section, we'll cover how Apollo Engine enables you to get detailed metrics about the performance of your GraphQL API.