backend-development

1# Backend Development
2 
3## API Design
4 
5### RESTful Conventions
6```
7GET    /users          # List users
8POST   /users          # Create user
9GET    /users/:id      # Get user
10PUT    /users/:id      # Update user (full)
11PATCH  /users/:id      # Update user (partial)
12DELETE /users/:id      # Delete user
13 
14GET    /users/:id/posts  # List user's posts
15POST   /users/:id/posts  # Create post for user
16```
17 
18### Response Format
19```json
20{
21  "data": { ... },
22  "meta": {
23    "page": 1,
24    "per_page": 20,
25    "total": 100
26  }
27}
28```
29 
30### Error Format
31```json
32{
33  "error": {
34    "code": "VALIDATION_ERROR",
35    "message": "Invalid input",
36    "details": [
37      { "field": "email", "message": "Invalid format" }
38    ]
39  }
40}
41```
42 
43## Database Patterns
44 
45### Schema Design
46```sql
47-- Use UUIDs for public IDs
48CREATE TABLE users (
49  id SERIAL PRIMARY KEY,
50  public_id UUID DEFAULT gen_random_uuid() UNIQUE,
51  email VARCHAR(255) UNIQUE NOT NULL,
52  created_at TIMESTAMPTZ DEFAULT NOW(),
53  updated_at TIMESTAMPTZ DEFAULT NOW()
54);
55 
56-- Soft deletes
57ALTER TABLE users ADD COLUMN deleted_at TIMESTAMPTZ;
58 
59-- Indexes
60CREATE INDEX idx_users_email ON users(email);
61CREATE INDEX idx_users_created ON users(created_at DESC);
62```
63 
64### Query Patterns
65```sql
66-- Pagination with cursor
67SELECT * FROM posts
68WHERE created_at < $cursor
69ORDER BY created_at DESC
70LIMIT 20;
71 
72-- Efficient counting
73SELECT reltuples::bigint AS estimate
74FROM pg_class WHERE relname = 'users';
75```
76 
77## Authentication
78 
79### JWT Pattern
80```typescript
81…