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Every EasySpawn article, newest first — deploying AI-built apps, Claude Code, databases, security, and the infrastructure underneath.
422 posts · page 7 of 18
Python vs JavaScript: Which Should a Beginner Choose?
Python and JavaScript are the two most popular first languages. How they differ in what they're for, how they look, speed, jobs and AI support — and a simple way to choose based on what you actually want to build.
Python Virtual Environments Explained: venv, pip, and uv for Beginners
Why every Python project needs its own virtual environment, how to create and activate one with venv on Windows, Mac and Linux, requirements.txt, the "externally-managed-environment" error, and why many people now use uv instead.
Primary Key vs Foreign Key: What's the Difference?
Primary keys identify each row; foreign keys link rows between tables. What each one does, examples in SQL, composite and unique keys, what ON DELETE CASCADE really means, and why AI-generated schemas sometimes skip foreign keys — and why you shouldn't.
PostgreSQL vs MySQL: Which Database Should You Choose?
Postgres and MySQL are the two most popular open-source databases. How they differ on features, JSON, extensions, performance, hosting and ecosystem — and why most new apps (and AI app builders) default to Postgres.
Postgres VACUUM and Table Bloat: How It Works and How to Keep It Under Control
Why Postgres tables bloat, what VACUUM and autovacuum actually do, tuning autovacuum for large tables, what blocks cleanup (long transactions, replication slots), transaction ID wraparound, and how to reclaim space without VACUUM FULL's exclusive lock.
Postgres Table Partitioning: When It Helps, When It Hurts, and How to Do It
Declarative partitioning in PostgreSQL: range, list and hash partitions, partition pruning, primary key and unique constraint rules, dropping old data instantly, automating new partitions, converting an existing table, and the cases where partitioning makes things slower.
Reading Postgres EXPLAIN ANALYZE: A Practical Guide to Query Plans
How to read a Postgres query plan: EXPLAIN vs EXPLAIN ANALYZE, BUFFERS, costs vs actual times, loops, scan and join types, spotting bad row estimates, sorts spilling to disk — plus pg_stat_statements and auto_explain for finding the queries worth fixing.
Postgres "Deadlock Detected": Why It Happens and How to Prevent It
ERROR: deadlock detected. How Postgres deadlocks happen, how to read the log detail, the common causes — inconsistent lock ordering, batch updates, foreign keys, upserts — and the fixes: consistent ordering, shorter transactions, explicit locking, and safe retries.
Postgres Connection Strings Explained: Format, Examples, and Common Errors
What every part of a PostgreSQL connection string (DATABASE_URL) means, how to write one, special characters in passwords, sslmode options, pooled vs direct connections (including Supabase's ports), and how to fix the errors people hit most.
Postgres Advisory Locks: Distributed Locking Without Redis
Advisory locks let your application lock arbitrary things — a job, a customer, a migration — using Postgres. Session vs transaction locks, blocking vs try-locks, turning strings into lock keys, the connection-pooler trap, and patterns for singleton cron jobs and per-entity mutexes.
PM2 vs systemd: How to Keep a Node.js App Running on a Server
When you run node app.js over SSH and log out, your app dies. How PM2 and systemd keep it running, restart it after crashes and reboots, handle logs and environment variables — with working configs for both, and where Docker fits.
pgvector Tutorial: Vector Search in Postgres for RAG and Semantic Search
Add semantic search and RAG to your app without a separate vector database. A hands-on pgvector guide: install the extension, store embeddings, query by cosine distance, add HNSW indexes, filter results correctly, choose dimensions and halfvec, and know when you've outgrown it.
Password Reset and Email Verification Flows Done Right
Password resets are one of the most attacked parts of any app. How to build reset and email-verification flows securely: token generation and hashing, expiry, account enumeration, host header poisoning, invalidating sessions, and the UX details that reduce support tickets.
The OWASP Top 10 (2025) Explained for Beginners and App Builders
The OWASP Top 10 is the most widely used list of web application security risks. All ten 2025 categories in plain English — from broken access control to supply chain failures — with what each looks like in an AI-built app and how to prevent it.
How to Optimize Images for the Web: Formats, Sizes, and Lazy Loading
Images are usually the heaviest part of a page. Which format to use (WebP vs AVIF vs JPEG vs PNG vs SVG), how big to make them, responsive images with srcset, lazy loading done right, and the one image you should never lazy-load.
npm vs pnpm vs Yarn vs Bun: Which Package Manager Should You Use?
Four JavaScript package managers install the same packages in different ways. How npm, pnpm, Yarn and Bun differ on speed, disk space, lockfiles and safety, which lockfile belongs to which, and why mixing them breaks things.
npm ERESOLVE "Unable to Resolve Dependency Tree": What It Means and How to Fix It
npm ERR! code ERESOLVE means two packages disagree about which version of a third they need. How to read the error, what peer dependencies are, the safe fixes in order, and when --legacy-peer-deps or --force are (and aren't) acceptable.
npm audit Explained: What the Warnings Mean and What to Actually Do
"found 14 vulnerabilities (3 moderate, 2 high)" — should you panic? How npm audit works, what the severity levels mean, why npm audit fix sometimes does nothing, why --force is risky, and how to tell real risks from noise.
Node.js vs Bun vs Deno: Which JavaScript Runtime in 2026?
Three runtimes run JavaScript outside the browser. How Node.js, Bun and Deno differ on speed, compatibility, TypeScript support, security and built-in tools — and why most apps should still start on Node.js.
Finding Memory Leaks in Node.js: Heap Snapshots, Retainers, and Common Culprits
Your Node.js server's memory climbs until it crashes. How to confirm a leak, read process.memoryUsage, capture heap snapshots in production safely, compare them in Chrome DevTools, follow retainer chains, and fix the usual causes: unbounded caches, listeners, timers and closures.
Next.js Hydration Errors: What They Mean and How to Fix Them
"Hydration failed because the server rendered HTML didn't match the client" — what hydration is, the usual culprits (dates, random values, window, browser extensions, invalid HTML, theme switchers), and the correct fix for each.
Mixed Content Errors: Why Your HTTPS Site Loads Things Over HTTP (and How to Fix It)
"Mixed Content: The page was loaded over HTTPS, but requested an insecure resource." What mixed content is, why browsers block it, how to find every http:// URL, and the fixes — including apps behind a proxy that generate http links.
Magic Link Login: How Passwordless Email Sign-In Works (and Its Pitfalls)
Magic links let people log in by clicking a link in their email — no password. How they work, when they're a good fit, the security details that matter (expiry, single use, token hashing), and the real-world problems: spam filters, email scanners and phones vs laptops.
Linux File Permissions Explained: chmod 755, 644, and "Permission Denied"
What rwxr-xr-x means, how chmod numbers like 755, 644 and 600 work, chmod +x for scripts, chown, the correct permissions for SSH keys, and why chmod 777 is never the right fix for "Permission denied".