When we audit codebases from clients switching to Ethersofts from another agency, the most common architectural mistake is tightly coupled frontend and backend code. The UI renders data that's generated in the same request cycle, making it impossible to add mobile apps, third-party integrations, or separate dashboards without duplicating business logic.
API-first architecture solves this by treating the API as the product. The frontend, mobile app, partner integrations, and admin tools all consume the same API. Business logic lives in one place, changes propagate everywhere, and adding new clients is trivial.
REST is sufficient for most applications. GraphQL adds value when clients need flexible queries — typically when a mobile app and web app need different data shapes from the same endpoint. Don't adopt GraphQL because it sounds modern; adopt it when your data access patterns demand it.
Rate limiting, versioning, and proper error responses are not optional. These are the things that separate a production API from a prototype. Every API we build at Ethersofts ships with OpenAPI documentation, rate limiting, structured error responses, and health check endpoints from day one.