COURSES + FIELD NOTES 12 courses · 8 disciplines EST. 2024

From a first script to a service in production.

WPSifero publishes courses and technical writing about programming. Five language courses — Python, JavaScript and TypeScript, PHP, SQL and Go — run from your first program to the parts you only meet under real traffic. Five more go deep into WordPress and WooCommerce, because that is where the two hardest things in this trade meet: a codebase you did not write, and a database under load.

Every course is text. No video, nothing to scrub through, nothing to re-watch at half speed. You read a lesson, type the code yourself, and finish with something that runs.

Browse the courses Read the articles

Curriculum status

$ wpsifero --curriculum

[ OK ]Go 1.24+18/18

[ OK ]Node 22 LTS+18/18

[ OK ]PHP 8.3+18/18

[ OK ]Python 3.12+18/18

[ OK ]MySQL · PostgreSQL · SQLite18/18

[ OK ]WordPress 7.0 · WooCommerce 11.218/18

[ OK ]WooCommerce 11.218/18

[ OK ]WordPress 7.018/18

[ OK ]WordPress 7.0 · PHP 8.5 · Claude Code · Codex · OpenCode18/18

[ OK ]WordPress 7.0 · Redis18/18

[ OK ]WordPress 7.018/18

[ OK ]WordPress 7.0 · PHP 8.3+18/18

$ _

Courses: 12
Lessons: 216
Articles: 107
Reading time: 134H 57M

01 Sector map

What you will find here

Three shelves: the languages, the platform, and the disciplines that apply to all of it.

LANG

The languages

Five courses, each running from your first program to the parts that only show up in production. Text, with a lab and a worked solution in every lesson.

Open the language courses

WP

WordPress and WooCommerce

The platform that runs a large share of the web, written against WordPress 7.0 and WooCommerce 11.2 rather than against tutorials from three versions ago.

Open the WordPress courses

DISC

The disciplines

The subjects that do not care which language you write: query budgets, cache invalidation, REST contracts, capability checks, accessibility, tooling.

Browse the articles

01 Lead transmission

This month's deep dive

Long-form work where the measurement matters more than the opinion.

Topic: WOO
Section: WooCommerce & Storefront
Published: 06 OCT 2026
Reading time: 7 MIN
Words: 1977W

Building Order Tracking in WooCommerce Without a Tracking Subscription

Most post-purchase support tickets are "where is my order". Here is the plugin architecture that answers them without shipping customer data to a tracking service.

Ana Ferreiro · @aferreiro

WooCommerce engineering

Covers the WooCommerce order lifecycle: checkout, HPOS, session handling, transactional email and the post-purchase layer where most storefront complaints actually originate.

Read the full analysis

02 Curriculum

Courses you read, not watch

12 complete text courses, 216 lessons, no video. Written to be read at your own pace and typed out rather than copied.

DEV05 COURSES

Programming track

Language and platform courses that start at a first script and end at the parts you only meet in production.

Go for Backend Services18 lessons · 10H 30M
JavaScript and TypeScript, from Script to Application18 lessons · 10H 15M
Modern PHP, from Syntax to Services18 lessons · 9H 21M
Python from First Script to Service18 lessons · 9H 25M
SQL and Relational Database Design18 lessons · 11H 10M

WP07 COURSES

WordPress track

Courses built against WordPress 7.0 and WooCommerce 11.2, covering plugin and block development through to performance and security.

Building the Sifero Courier Timeline Plugin18 lessons · 8H 50M
WooCommerce Extension Development18 lessons · 10H 35M
WordPress Block Themes and Full Site Editing18 lessons · 10H 00M
WordPress Development with AI Agents18 lessons · 10H 15M
WordPress Performance and Scaling18 lessons · 10H 25M
WordPress Plugin Development18 lessons · 8H 45M
WordPress Security and Hardening18 lessons · 10H 45M

Open the course catalogue How this material is written

02 Transmission log

Latest articles

Newest first. Every entry is tagged by discipline and carries an estimated reading time.

001 The second interface problem: who learns the builder, and who pays A page builder gives a client a second interface to learn, and they will use it for everything. What that does to content, handover and maintenance. WP Ana Ferreiro 19 OCT 2026 · 9M 002 A builder migration is a coverage number, not a switch Divi 5's migrator converts supported modules and leaves the rest on the old framework. How to count module coverage across pages before scheduling a migration. WP Tomas Lindqvist 19 OCT 2026 · 9M 003 How to inspect what a page builder stored in the database Three SQL queries show whether a WordPress site stores pages as shortcodes, blocks or both, and how to read the answer before quoting or accepting a migration. WP Tomas Lindqvist 19 OCT 2026 · 8M 004 Before making a Divi module global, ask three questions A global Divi module edits every page that uses it. The three questions to ask before making one, and the parts of a client site that should never be global. WP Devon Parker 19 OCT 2026 · 9M 005 Evaluating a page builder in an afternoon, on a staging site Six tests a team can run on a staging site in one afternoon, covering reusable headers, custom post types, content exports and the editor who changes a price. WP Priya Raghunathan 19 OCT 2026 · 9M 006 A Divi licence is a bet on how long the agency keeps building sites Both Divi plans cover unlimited websites, so yearly versus lifetime is a question of horizon, and the real agency cost is the interface clients must learn. WP Martin Kiel 19 OCT 2026 · 9M 007 Whose licence is the site running on when the client leaves An unlimited-site builder licence covers a client's site until the working relationship ends. Three arrangements, the year-two cost of each, and the clause to sign. WP Martin Kiel 19 OCT 2026 · 9M 008 The First Three Security Plugins a Small WordPress Site Should Install Most small WordPress sites are lost to three boring things: an unpatched plugin, a reused admin password, a theme from a forum. Here is the order to fix them. SEC Tomas Lindqvist 17 OCT 2026 · 9M 009 Comment spam is a security problem, not an inbox problem Comment forms are the most probed input on a WordPress site, and the spam is the visible fraction. What the traffic is doing and what each filter costs. SEC Tomas Lindqvist 17 OCT 2026 · 9M

Open the complete index (107 articles)

04 Sector map

Topics

Eight disciplines, each with its own archive and its own set of recurring failure modes.

WP30

WordPress Internals

Hooks, the database layer, cron, and the parts of core that decide how your plugin behaves under load.

WOO13

WooCommerce & Storefront

Order lifecycle, checkout, HPOS, sessions and the post-purchase communication layer.

PERF10

Performance

Query budgets, object caching, Core Web Vitals and measuring before you optimise.

API06

APIs & Integrations

REST design, webhooks, authentication, idempotency and talking to couriers and ERPs.

SEC10

Security & Hardening

Capability checks, nonces, sanitisation, SQL safety and threat modelling for plugins.

FE14

Frontend & Accessibility

Block themes, progressive enhancement, ARIA, and interfaces that work without JavaScript.

TOOL08

Tooling & Workflow

Local environments, static analysis, CI, release packaging and debugging technique.

INFRA16

Hosting & Infrastructure

Server configuration, caching layers, queues, observability and deployment practice.

05 Operating principle

What we publish, and what we refuse to

This section exists so readers and reviewers can hold us to a stated standard.

Every claim is reproducible

Performance numbers come from a stated environment. We publish the query count, the cache state and the sample size, because a benchmark without its conditions is an advertisement rather than a measurement.

Disagreement is documented

Where a recommended pattern has a cost, that cost appears in the same article rather than a follow-up. If an approach fails past a certain order volume, we say at which volume it fails.

No undisclosed interests

WPSifero maintains its own plugins. Whenever an article touches a product we build, the relationship is disclosed inside that article, at the top, in plain language.

Read the full editorial standards