System design patterns
Sharding, load balancing, CAP tradeoffs, and scaling patterns — interview and production ready.
How to Build an Adapter to Translate External API Responses in Python
Build an adapter class that translates a mock external API's response shape into your internal representation, keeping callers decoupled from the external contract.
import json
from typing import Dict, Any
class ExternalAPI:
"""Mock external service returning a different data shape."""
def get_user(self, user_id: int) -> Dict[str, Any]:
return {
"id": user_id,
"full_name": "Jane Doe",
"email_address": "jane@example.com",
…How to Migrate a Legacy Facade with the Strangler Fig Pattern in Python
Use a facade to wrap a legacy API and incrementally migrate callers to a modern interface, following the strangler fig pattern.
class LegacyAPI:
"""Simulates the legacy system's raw interface."""
def get_user(self, user_id):
return {"id": user_id, "name": "Alice", "legacy": True}
class UserService:
"""Facade that wraps the legacy system with a modern interface."""
def __init__(self, legacy_api=None):
self.lega…Browse by section
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System design patterns — Python code examples
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This page collects system design patterns snippets — short, copy-ready Python you can paste into our free online IDE and run without installing anything. Each sample includes a plain-English explanation and the full source code.
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Samples are quick reference — one concept per page. For step-by-step teaching, use our Python tutorials. To test yourself, try quizzes or coding challenges. Clean up style with the Python formatter.