the engineering
notebook.

A critical PHP fix on a server whose Ubuntu no longer gets updates

PHP forgets, Python remembers. It comes down to the execution model

Cloudflare cached HTML instead of CSS: notes from moving a static site

Zero is not missing data: modelling "measured", "not provided" and "unreadable"

Go/no-go on 6 June 1944: what a release decision is made of

RAG ingestion in n8n: document versions, deletions and freshness metadata

The hidden cost of microservice boundaries: how to price a boundary before you draw it

AI agents as state graphs in LangGraph: checkpoints, interrupts and replay

Postgres with more than one writer: primary keys and how to migrate them

LLMs in a PHP application: queues, idempotency and validation instead of a Python rewrite

Singleton in PHP: what "one instance" means under PHP-FPM, Octane and PHPUnit

Factory Method in PHP: one place for a runtime choice of implementation

Ansible in production: idempotency, drift detection and safe rolling changes

State machines in PHP: an explicit order lifecycle with enums, locks and events

The Bridge pattern: separating what you send from how you send it

PHP references: what & actually does and where it breaks code

Design patterns in production PHP: what each one buys, what it costs, when to skip it