Production notes from a builder who ships, operates, and occasionally breaks his own AI systems.
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A load balancer distributes incoming requests across multiple servers to prevent any single server from becoming a bottleneck. Learn how round-robin routing, health checks, and redundancy keep sites online during traffic spikes.
Symmetric encryption uses one shared key (fast, hard to distribute). Asymmetric uses a public/private pair (solves key distribution, but slow). Real systems use both—like HTTPS and JWTs.
An API gateway puts a single front door in front of all your services — one entrance every request has to pass through, including the bad ones. Here's the problem it solves, how it terminates TLS, authenticates, rate-limits, routes, and aggregates in one place, and why the same idea now guards your LLM calls too.
CORS isn't browser gatekeeping—it stops an attack where cross-site requests auto-attach your login cookies. Learn the threat, the same-origin policy, and the one-line server fix.
VPN and DNS both unblock content, but operate at different layers. VPN encrypts all traffic through a remote server; DNS only resolves names to IPs. Only VPN provides real privacy.
Encryption is reversible (lock and unlock with a key); hashing is one-way (no way back). Learn when to use each, why passwords must always be hashed, and how salt and slow hashing defeat brute-force attacks.
Why one login gives you two tokens: access tokens are short-lived and sent everywhere (small blast radius if stolen), refresh tokens are long-lived and server-tracked (enabling real logout). Together they escape the single-token security-vs-UX trade-off.
Stateless servers forget you after each request, scaling infinitely but requiring every call to carry full context. Stateful servers remember you, enabling natural continuity but pinning you to one node.
Should raw image and video bytes live inside your database or in object storage like S3? Stuffing files into a bytea/BLOB column keeps everything in one place and works for a weekend project — then backups drag terabytes through your most expensive tier and reads pull huge binaries through the connection pool. Here's why object storage plus a tiny DB reference plus short-lived pre-signed URLs is how the big apps actually store media — and how the same pattern serves model weights and generated media for LLM apps.
Production-shaped code you can clone, read, and run — the same patterns I write about.
