Build Better APIs with Practical Contract Rules

Great APIs are predictable. The simplest way to achieve that is to design clear contracts and be strict about consistency.

#Start with stable naming

Use nouns for resources and keep naming patterns uniform across the API surface. If you use createdAt in one response, avoid switching to created_on elsewhere.

#Treat errors as first-class

Error payloads should have a consistent shape, for example:

{
  "code": "VALIDATION_ERROR",
  "message": "Email is required",
  "field": "email"
}

This reduces conditional logic in clients and makes troubleshooting easier.

#Version with intention

If a change breaks existing consumers, version explicitly and document migration steps. Contract safety is a feature, not optional polish.