RESTful API vs GraphQL in Production: Trade-offs, N+1 Problem & Caching Reality

+---------------------+-------------------------------+-------------------------------+
| Dimension           | RESTful API                   | GraphQL API                   |
+---------------------+-------------------------------+-------------------------------+
| Data Fetching       | Fixed endpoints (Over/Under)  | Exact field specification     |
| Network Roundtrips  | Multiple endpoints per page   | Single request payload        |
| HTTP Edge Caching   | Trivial (GET /resource/123)   | Complex (POST queries)        |
| Server Overhead     | Low (Direct ORM mapping)      | High (AST parsing & validation|
| Schema Evolution    | URI Versioning (/v1, /v2)     | Deprecation annotations       |
+---------------------+-------------------------------+-------------------------------+

Query: Get 100 Posts and their Authors
Naive Resolver:
1 query to fetch 100 posts
+ 100 individual queries to fetch each author! (💥 101 DB queries!)

import DataLoader from 'dataloader';

// Batch load authors in a single query: SELECT * FROM users WHERE id IN (...)
const authorLoader = new DataLoader<string, User>(async (authorIds) => {
  const users = await db.user.findMany({
    where: { id: { in: [...authorIds] } },
  });
  const userMap = new Map(users.map((u) => [u.id, u]));
  return authorIds.map((id) => userMap.get(id));
});