1. Naming rules
2. Type rules
- 2.1. Use custom scalar types if you want to declare fields or args with specific semantic value.
- 2.2. Use Enum for fields which contain a specific set of values.
3. Field Rules (Output)
4. Argument rules (Input)
5. Rules of lists
6. Mutation rules
7. Rules of linkages between types (relationships)
- 7.1. GraphQL schema should be "hairy"
8. Authorization
- 8.1. Schema diffing based authorization
9. Other rules
- 10.1. Use markdown for documentation
A. Appendix
- A-1 Useful links
Credits

3. Field Rules (Output)

In GraphQL fields are used to describe the shape of data that will be transferred from the server to the client. They may be described as scalar types as well as complex structures - Object type (GraphQLObjectType).

3.1. Use semantic names for fields and avoid leaking of implementation details in fields names.

3.2. Use Non-Null field if field will always have a given field value.

3.3. Group as many related fields into custom Object type as possible.