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System design patterns

Sharding, load balancing, CAP tradeoffs, and scaling patterns — interview and production ready.

6 matches

Build a BFF (Backend for Frontend) Mock Aggregator in Python

A minimal HTTP server implementing the BFF pattern that aggregates user data and orders from two mock backends into a single JSON response.

bff http-server aggregation

Python

import json
from http.server import BaseHTTPRequestHandler, HTTPServer
from urllib.parse import urlparse


class MockBackendA:
    def get_user(self, user_id):
        return {"id": user_id, "name": "Alice", "service": "backend-a"}


class MockBackendB:
    def get_orders(self, user_id):
        return [
            {…

18 0 Open

System design patterns easy

How to Build an MVP Presenter View Mock in Python

A minimal MVP (Model-View-Presenter) mock showing a Presenter controlling a SlideDeck model with slide navigation and typed state via dataclasses.

dataclasses mvp design-patterns

Python

from dataclasses import dataclass, field
from typing import List


@dataclass
class SlideDeck:
    title: str
    slides: List[str] = field(default_factory=list)
    current_index: int = 0

    def next_slide(self) -> str:
        if self.current_index < len(self.slides) - 1:
            self.current_index += 1
      …

13 0 Open

System design patterns medium

How to Implement a Simple MVVM Binding Mock in Python

A minimal Python implementation of the MVVM pattern, mocking data binding so views auto-update when the view model changes.

mvvm binding observer pattern

Python

class BindingMock:
    def __init__(self, view_model):
        self.view_model = view_model
        self.subscribers = []

    def bind(self, property_name, callback):
        self.subscribers.append((property_name, callback))

    def set(self, property_name, value):
        setattr(self.view_model, property_name, va…

18 0 Open

System design patterns medium

Implement a Consistent Hash Ring in Python

Build a minimal consistent hash ring with virtual nodes to map keys to servers stably as nodes are added or removed.

consistent-hashing hashing distributed-systems

Python

import hashlib
import bisect


class ConsistentHashRing:
    def __init__(self, nodes=None, replicas=3):
        self.replicas = replicas
        self.ring = {}
        self.sorted_keys = []
        if nodes:
            for node in nodes:
                self.add_node(node)

    def _hash(self, key):
        return i…

15 0 Open

System design patterns medium

Microkernel Plug-in Core Mock in Python

Implements a minimal microkernel plug-in core that registers, unregisters, and executes synchronous or asynchronous plugins via a pluggable manager class.

microkernel plugin design-patterns

Python

import json
import abc
import inspect


class MicrokernelCore(abc.ABC):

    def __init__(self):
        self._plugins = {}

    def register(self, name, plugin):
        self._plugins[name] = plugin

    def unregister(self, name):
        return self._plugins.pop(name, None)

    def execute(self, name, *args, **kwa…

13 0 Open

System design patterns easy

Python MVC Pattern Example (Model-View-Controller)

A minimal, runnable Model-View-Controller (MVC) example in pure Python that separates data, presentation, and logic.

mvc design-pattern architecture

Python

class Model:
    def __init__(self):
        self.data = {"title": "Initial Title", "content": "Initial Content"}

    def get_data(self):
        return self.data

    def update_data(self, title=None, content=None):
        if title:
            self.data["title"] = title
        if content:
            self.data["c…

15 0 Open

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