# Python Backend Technology Stack Recommendations

This document provides curated recommendations for common technology choices in Python backend development.

## Web Frameworks

### FastAPI (Recommended for Modern APIs)
**Best for:** Microservices, RESTful APIs, async-first applications

**Pros:**
- Automatic OpenAPI/Swagger documentation
- Built-in request/response validation with Pydantic
- High performance (comparable to Node.js/Go)
- Native async/await support
- Type hints and IDE support
- Modern Python features

**Cons:**
- Smaller ecosystem compared to Django
- Less built-in features (need to integrate more libraries)
- Newer framework (less mature)

**When to use:**
- Building new REST or GraphQL APIs
- High-performance requirements
- Microservices architecture
- Team comfortable with modern Python

### Django (Recommended for Full-Featured Applications)
**Best for:** Monolithic applications, admin-heavy apps, rapid development

**Pros:**
- Batteries-included (ORM, admin, auth, forms, etc.)
- Massive ecosystem and community
- Battle-tested and mature
- Excellent documentation
- Built-in admin interface
- Strong security defaults

**Cons:**
- Heavier framework
- Less suitable for microservices
- Async support is newer and limited
- More opinionated structure

**When to use:**
- Building full-featured web applications
- Need admin interface out of the box
- Rapid prototyping
- Team prefers convention over configuration

### Flask (Recommended for Simple APIs)
**Best for:** Small to medium applications, prototypes, simple APIs

**Pros:**
- Lightweight and flexible
- Easy to learn
- Large ecosystem of extensions
- Minimal boilerplate
- Great for prototypes

**Cons:**
- Requires more setup for production
- No built-in async support (requires extensions)
- Need to choose and integrate many components
- Less structure by default

**When to use:**
- Small to medium applications
- Prototypes and MVPs
- Learning Python web development
- Need maximum flexibility

## Async Frameworks

### Comparison
| Feature | FastAPI | Starlette | Quart | aiohttp |
|---------|---------|-----------|-------|---------|
| Performance | Excellent | Excellent | Good | Excellent |
| Documentation | Excellent | Good | Good | Good |
| Ease of Use | Excellent | Good | Excellent | Moderate |
| Community | Growing | Moderate | Small | Moderate |
| Best For | APIs | Custom apps | Flask users | Low-level control |

## Database Solutions

### PostgreSQL (Recommended for Most Cases)
**Best for:** Production applications requiring ACID compliance

**Pros:**
- ACID compliant
- Rich feature set (JSONB, full-text search, etc.)
- Excellent performance
- Strong community
- Great for complex queries

**Libraries:**
- `asyncpg` - Fastest async driver
- `psycopg2` - Traditional sync driver
- `psycopg3` - Modern sync/async driver

### MySQL/MariaDB
**Best for:** Applications with heavy read operations

**Pros:**
- Fast read performance
- Wide hosting support
- Good replication
- Mature ecosystem

**Libraries:**
- `aiomysql` - Async driver
- `mysqlclient` - Sync driver (fastest)
- `PyMySQL` - Pure Python sync driver

### MongoDB
**Best for:** Flexible schema, document-oriented data

**Pros:**
- Schema flexibility
- Horizontal scaling
- Good for rapid development
- Rich query language

**Libraries:**
- `motor` - Async driver (recommended)
- `pymongo` - Sync driver

### Redis
**Best for:** Caching, sessions, real-time features

**Pros:**
- Extremely fast
- Rich data structures
- Pub/sub support
- Good for caching and sessions

**Libraries:**
- `redis-py` - Official client with async support
- `aioredis` - Async-first client (now merged into redis-py)

## ORM Solutions

### SQLAlchemy (Recommended)
**Best for:** Complex queries, database agnostic code

**Pros:**
- Most mature Python ORM
- Powerful query API
- Database agnostic
- Great documentation
- Good async support (2.0+)

**Cons:**
- Steeper learning curve
- More verbose than alternatives

```python
# Async SQLAlchemy 2.0
from sqlalchemy.ext.asyncio import create_async_engine, AsyncSession
from sqlalchemy.orm import declarative_base, sessionmaker

engine = create_async_engine("postgresql+asyncpg://user:pass@localhost/db")
AsyncSessionLocal = sessionmaker(engine, class_=AsyncSession, expire_on_commit=False)
```

### Tortoise ORM
**Best for:** Async-first applications, Django-like syntax

**Pros:**
- Built for async from the ground up
- Django-like API
- Easy to learn
- Good documentation

**Cons:**
- Smaller community
- Fewer features than SQLAlchemy
- Limited database support

```python
from tortoise import fields, models
from tortoise.contrib.fastapi import register_tortoise

class User(models.Model):
    id = fields.IntField(pk=True)
    email = fields.CharField(max_length=255, unique=True)
    name = fields.CharField(max_length=255)
```

### Django ORM
**Best for:** Django projects

**Pros:**
- Integrated with Django
- Simple and intuitive
- Excellent documentation
- Good async support (3.1+)

**Cons:**
- Tied to Django
- Less powerful than SQLAlchemy for complex queries

## API Documentation

### OpenAPI/Swagger (FastAPI Built-in)
**Recommended for:** REST APIs

**Libraries:**
- FastAPI includes automatic generation
- `flasgger` for Flask
- `drf-spectacular` for Django REST Framework

### GraphQL

**Strawberry (Recommended for FastAPI)**
```python
import strawberry
from fastapi import FastAPI
from strawberry.fastapi import GraphQLRouter

@strawberry.type
class Query:
    @strawberry.field
    def hello(self) -> str:
        return "Hello World"

schema = strawberry.Schema(query=Query)
graphql_app = GraphQLRouter(schema)
```

**Other Options:**
- `Graphene` - Mature, works with Django
- `Ariadne` - Schema-first approach

## Authentication & Authorization

### JWT Authentication
**Libraries:**
- `python-jose[cryptography]` - Recommended for JWT
- `PyJWT` - Lightweight alternative

```python
from jose import JWTError, jwt
from datetime import datetime, timedelta

def create_access_token(data: dict):
    to_encode = data.copy()
    expire = datetime.utcnow() + timedelta(minutes=15)
    to_encode.update({"exp": expire})
    return jwt.encode(to_encode, SECRET_KEY, algorithm=ALGORITHM)
```

### OAuth2
**Libraries:**
- `authlib` - Comprehensive OAuth client/server
- `python-social-auth` - Social authentication

### Password Hashing
**Libraries:**
- `passlib[bcrypt]` - Recommended
- `argon2-cffi` - Most secure (memory-hard)

```python
from passlib.context import CryptContext

pwd_context = CryptContext(schemes=["bcrypt"], deprecated="auto")

def hash_password(password: str) -> str:
    return pwd_context.hash(password)

def verify_password(plain_password: str, hashed_password: str) -> bool:
    return pwd_context.verify(plain_password, hashed_password)
```

## Task Queues

### Celery (Recommended for Most Cases)
**Best for:** Complex workflows, scheduled tasks

**Pros:**
- Mature and battle-tested
- Rich feature set
- Good monitoring tools
- Supports multiple brokers

**Cons:**
- Complex configuration
- Heavy dependency

```python
from celery import Celery

app = Celery('tasks', broker='redis://localhost:6379/0')

@app.task
def process_data(data):
    # Long-running task
    pass
```

### RQ (Redis Queue)
**Best for:** Simple job queues

**Pros:**
- Simple to use
- Lightweight
- Good for simple tasks

**Cons:**
- Less features than Celery
- Only works with Redis

### Dramatiq
**Best for:** Alternatives to Celery

**Pros:**
- Simpler than Celery
- Good performance
- Type-safe

**Cons:**
- Smaller community

## Validation & Serialization

### Pydantic (Recommended)
**Best for:** Data validation, settings management

```python
from pydantic import BaseModel, EmailStr, validator

class User(BaseModel):
    id: int
    email: EmailStr
    name: str
    age: int

    @validator('age')
    def validate_age(cls, v):
        if v < 0:
            raise ValueError('Age must be positive')
        return v
```

### Marshmallow
**Best for:** Flask applications, complex serialization

## HTTP Clients

### httpx (Recommended)
**Best for:** Modern async/sync HTTP client

```python
import httpx

async with httpx.AsyncClient() as client:
    response = await client.get('https://api.example.com')
```

### aiohttp
**Best for:** Async-only applications

### requests
**Best for:** Sync-only applications (legacy)

## Testing

### pytest (Recommended)
**Essential plugins:**
- `pytest-asyncio` - Async test support
- `pytest-cov` - Coverage reporting
- `pytest-mock` - Mocking utilities
- `pytest-xdist` - Parallel testing

```python
import pytest
from httpx import AsyncClient

@pytest.mark.asyncio
async def test_create_user(client: AsyncClient):
    response = await client.post("/users", json={"email": "test@example.com"})
    assert response.status_code == 201
```

### Other Tools
- `coverage` - Code coverage
- `faker` - Test data generation
- `factory_boy` - Test fixtures
- `responses` - Mock HTTP requests

## Observability

### Logging
**Recommended:**
- `structlog` - Structured logging
- `python-json-logger` - JSON logging
- Built-in `logging` module

### Metrics
**Recommended:**
- `prometheus-client` - Prometheus metrics
- `statsd` - StatsD client

### Tracing
**Recommended:**
- `opentelemetry-api` + `opentelemetry-sdk` - OpenTelemetry
- `ddtrace` - DataDog APM
- `sentry-sdk` - Error tracking

```python
from opentelemetry import trace
from opentelemetry.sdk.trace import TracerProvider

trace.set_tracer_provider(TracerProvider())
tracer = trace.get_tracer(__name__)

with tracer.start_as_current_span("process_data"):
    # Your code here
    pass
```

## Security

### Security Headers
```python
from fastapi.middleware.trustedhost import TrustedHostMiddleware
from fastapi.middleware.cors import CORSMiddleware

app.add_middleware(TrustedHostMiddleware, allowed_hosts=["example.com"])
app.add_middleware(
    CORSMiddleware,
    allow_origins=["https://example.com"],
    allow_credentials=True,
    allow_methods=["*"],
    allow_headers=["*"],
)
```

### Security Libraries
- `bandit` - Security linting
- `safety` - Dependency vulnerability scanning
- `python-dotenv` - Environment variable management

## Development Tools

### Code Quality
- `ruff` - Fast linter and formatter (recommended)
- `black` - Code formatter
- `isort` - Import sorting
- `mypy` - Static type checking
- `pylint` - Comprehensive linting

### Dependency Management
- `poetry` - Recommended for modern projects
- `pdm` - Fast alternative to poetry
- `pip-tools` - Minimal approach (pip-compile)

### Pre-commit Hooks
```yaml
# .pre-commit-config.yaml
repos:
  - repo: https://github.com/astral-sh/ruff-pre-commit
    rev: v0.1.6
    hooks:
      - id: ruff
        args: [--fix]
      - id: ruff-format

  - repo: https://github.com/pre-commit/mirrors-mypy
    rev: v1.7.1
    hooks:
      - id: mypy
```

## Deployment

### ASGI Servers
- `uvicorn` - Recommended for FastAPI
- `hypercorn` - HTTP/2 support
- `daphne` - Django channels

### WSGI Servers
- `gunicorn` - Recommended for Django/Flask
- `uwsgi` - Alternative option

### Production Setup
```bash
# Uvicorn with Gunicorn (recommended for production)
gunicorn main:app -w 4 -k uvicorn.workers.UvicornWorker
```

## Configuration Management

### Pydantic Settings (Recommended)
```python
from pydantic_settings import BaseSettings

class Settings(BaseSettings):
    database_url: str
    redis_url: str
    secret_key: str

    class Config:
        env_file = ".env"
```

### python-decouple
Simple alternative for basic configuration

## Message Brokers

### RabbitMQ
**Best for:** Complex routing, guaranteed delivery

**Libraries:**
- `aio-pika` - Async AMQP client

### Apache Kafka
**Best for:** Event streaming, high throughput

**Libraries:**
- `aiokafka` - Async Kafka client
- `confluent-kafka` - High-performance client

### Redis Pub/Sub
**Best for:** Simple pub/sub, low latency

**Libraries:**
- `redis-py` with pub/sub support

## Recommended Stack Combinations

### Modern Microservices Stack
- Framework: FastAPI
- Database: PostgreSQL (asyncpg)
- ORM: SQLAlchemy 2.0 (async)
- Cache: Redis
- Task Queue: Celery or Dramatiq
- Validation: Pydantic
- Testing: pytest + httpx
- Observability: OpenTelemetry + Sentry
- Deployment: Uvicorn + Docker + Kubernetes

### Traditional Monolith Stack
- Framework: Django
- Database: PostgreSQL (psycopg2)
- ORM: Django ORM
- Cache: Redis
- Task Queue: Celery
- API: Django REST Framework
- Testing: pytest-django
- Deployment: Gunicorn + Docker

### Lightweight API Stack
- Framework: Flask or FastAPI
- Database: PostgreSQL or MongoDB
- ORM: SQLAlchemy or Motor
- Testing: pytest
- Deployment: Uvicorn or Gunicorn

## Version Recommendations (as of 2025)

```toml
# pyproject.toml
[tool.poetry.dependencies]
python = "^3.11"  # Python 3.11+ recommended for performance
fastapi = "^0.110.0"
uvicorn = {extras = ["standard"], version = "^0.27.0"}
sqlalchemy = "^2.0.25"
asyncpg = "^0.29.0"
pydantic = "^2.5.0"
pydantic-settings = "^2.1.0"
redis = "^5.0.1"
celery = "^5.3.4"
python-jose = {extras = ["cryptography"], version = "^3.3.0"}
passlib = {extras = ["bcrypt"], version = "^1.7.4"}
httpx = "^0.26.0"
structlog = "^24.1.0"
opentelemetry-api = "^1.22.0"
opentelemetry-sdk = "^1.22.0"
sentry-sdk = "^1.39.0"

[tool.poetry.group.dev.dependencies]
pytest = "^7.4.4"
pytest-asyncio = "^0.23.3"
pytest-cov = "^4.1.0"
ruff = "^0.1.9"
mypy = "^1.8.0"
```

This technology stack provides battle-tested, production-ready solutions for Python backend development in 2025.