Architecture
How the pieces of an app fit together — frontends and backends, APIs, databases, queues and caches — and how to choose between designs.
84 posts · page 1 of 4
What Is a Load Balancer? Spreading Traffic Across Servers
A load balancer sits in front of several copies of your app and spreads requests between them, skipping any that are unhealthy. How it works, the common algorithms, sticky sessions, health checks, and why a small app probably doesn't need one yet.
What Is a Headless CMS? And Does Your App Need One?
A headless CMS is a content editor with no website attached — it stores your content and hands it to your app through an API. How it differs from WordPress, the popular options, when it beats Markdown files or your own database, and when it's overkill.
TanStack Query vs useEffect for Data Fetching in React
Fetching in useEffect looks simple until you need loading states, errors, caching, race conditions, refetching and mutations. What TanStack Query handles for you, side-by-side code, mutations with invalidation, and when server components or plain useEffect are still the right choice.
Stripe Subscriptions Explained: Products, Prices, Webhooks and Access
How Stripe Billing models subscriptions — customers, products, prices, subscriptions and invoices — which webhooks to handle, what each subscription status means for access, trials, upgrades and proration, failed payments and dunning, and the Customer Portal.
React State Management: useState vs Context vs Zustand vs Redux
Most React apps need less state management than they think. Sort your state into server, URL, form, local and global, then pick the lightest tool for each: useState, the URL, React Context, Zustand, Redux Toolkit or Jotai. Trade-offs, examples and common mistakes.
React Server Components Explained: "use client", "use server", and What Runs Where
Server Components render on the server and send no JavaScript; Client Components hydrate in the browser for interactivity. How the boundary works, what 'use client' and 'use server' actually mean, passing data across, common errors, and how to keep secrets and bundles where they belong.
Optimistic vs Pessimistic Locking: Preventing Lost Updates
Two users edit the same record and one silently overwrites the other. Pessimistic locking (SELECT FOR UPDATE) blocks the second writer; optimistic locking (a version column) detects the conflict. How each works, code for both, atomic updates that avoid locks entirely, and how to choose.
Next.js App Router vs Pages Router: Differences and Whether to Migrate
Next.js has two routers: the older pages/ directory and the newer app/ directory built on React Server Components. How routing, data fetching, layouts and API routes differ, which one new projects should use, and a sensible incremental migration path.
Message Queues Explained: When You Need One and Which to Use
A message queue lets one part of your system hand work to another without waiting. Queues vs pub/sub vs event streams, delivery guarantees, dead-letter queues, and an honest comparison of Postgres, Redis, RabbitMQ, SQS and Kafka for a small team.
HTTP/1.1 vs HTTP/2 vs HTTP/3: What Changed and Whether You Should Care
HTTP/2 multiplexed requests over one TCP connection; HTTP/3 moved to QUIC over UDP to escape TCP's head-of-line blocking and speed up handshakes. How each works, what they fix, what they break, how browsers discover HTTP/3, and what to actually configure for your app.
How Coding Agents Work: The Loop, the Tools, and the Context Behind Them
Under the hood, Claude Code, Codex and similar agents are a model in a loop with tools and a carefully managed context. The agent loop, tools, file editing, search, context compaction, subagents, permissions and sandboxing — and what it means for you.
GET vs POST (and PUT, PATCH, DELETE): HTTP Methods Explained
Every request to a web server has a method that says what it wants to do. GET reads, POST creates, PUT and PATCH update, DELETE removes. The differences that matter in practice — caching, safety, idempotency, where the data goes — and the mistakes AI-generated APIs make.
Flask vs Django vs FastAPI: Which Python Web Framework?
Three popular Python web frameworks with different philosophies. Django is batteries-included, Flask is minimal, FastAPI is built for typed, async APIs. What each gives you, the same endpoint in all three, and how to pick for your project.
Database Normalization Explained: 1NF, 2NF, 3NF in Plain English
Normalization means storing each fact once, so updates can't leave your data contradicting itself. What 1NF, 2NF and 3NF actually require, with one example table taken through each step, the anomalies they prevent, and when deliberately denormalizing is the right call.
API Authentication Methods: API Keys, Sessions, JWTs, OAuth and mTLS
How should clients prove who they are to your API? API keys for server-to-server, session cookies for your own web app, bearer tokens for mobile and SPAs, OAuth for third-party access, HMAC signatures for webhooks, mTLS for service meshes. When to use each and how to do it safely.
What Is RAG? Retrieval-Augmented Generation for Beginners
RAG lets an AI answer questions about your own documents by finding the relevant pieces first and handing them to the model. How retrieval-augmented generation works, step by step, when you need it, when you don't, and the mistakes that make it give bad answers.
What Is Python? What It's Used For and Why AI Loves It
Python is a popular, readable programming language used for websites, automation, data and AI. What Python is, what it looks like, what people build with it, how to run a Python file, and when an app should use Python instead of JavaScript.
What Is Latency? Why Distance Makes Your App Feel Slow
Latency is the delay before data arrives; bandwidth is how much can arrive at once. What latency is, why physical distance sets a floor on it, why round trips multiply it, latency vs bandwidth vs throughput, and practical ways to make an app feel faster for faraway users.
What Is Function Calling (Tool Calling) in AI? Explained With Examples
Function calling — also called tool calling or tool use — lets an AI model ask your code to do things: look up an order, check the weather, query a database. How it works step by step, a Claude example, why the model never runs your code itself, and how to keep it safe.
What Is an SDK? SDK vs API, Explained for Beginners
An SDK is a ready-made toolkit for using a service from your code. What an SDK contains, how it differs from an API, real examples from Stripe and Anthropic, how to install one, and why AI tools sometimes invent SDK functions that don't exist.
What Is a PWA? Progressive Web Apps Explained for Beginners
A progressive web app is a website that can be installed like an app, work offline and send notifications. What a PWA needs (manifest, service worker, HTTPS), what it can and can't do on iPhone and Android, and when it's a better first step than an app-store app.
UUID vs Auto-Increment IDs: Which Primary Key Should You Use?
Sequential integers or UUIDs for your primary keys? The real trade-offs — size, index performance, guessability, merging data, leaking business metrics — why UUIDv7 changes the answer, Postgres 18's uuidv7(), and the common hybrid of internal IDs plus public IDs.
Two-Factor Authentication Explained (and How to Add It to Your App)
What two-factor authentication is, how authenticator-app codes (TOTP) work, why SMS codes are the weakest option, where passkeys fit, and how to add 2FA to your own app — including recovery codes and the mistakes to avoid.
Subdomain vs Subdirectory: blog.example.com or example.com/blog?
Should your blog, docs or app live on a subdomain (app.example.com) or a subdirectory (example.com/app)? The technical differences, what it means for SEO, cookies and hosting, and sensible defaults for a small product.