No generic guides here. Each note is the diagnosis and fix for a problem genuinely encountered in a live system — symptoms, wrong diagnoses, root cause and a verified correction.
Diagnosis and fix records from problems encountered in live client systems. Topics: writing a meal-card (Multinet, Sodexo) payment gateway for WooCommerce and the security mistake in the return step; the deferred-JavaScript root cause behind the "your cart is empty" error in block checkout; which .htaccess directives silently produce 403s on OpenLiteSpeed; the five decisions that determine a restaurant POS architecture; and the four interventions that actually make WordPress fast.
These problems share a property: each is either absent from the available material or covered superficially. Someone searching the "your cart is empty" error typically meets the advice "clear your cache" — advice with no relationship at all to the real cause.
These notes fill that gap. Each follows the same structure:
The notes address two readers at once: the developer who wants to solve it themselves, and the business owner who wants to understand what is happening in their system. That is why each note opens with a non-technical short answer; detail and code come after.
For the real projects where these problems were solved, see the case studies.
The samples are simplified from working installations and the logic is directly applicable. Still, take a backup before trying them on your own system and run them in a staging environment where possible — especially for anything touching the payment flow.
Do not skip the diagnosis steps; the most common mistake is jumping to the fix because the symptom looks similar. For example, in the "empty cart" case, if you do not see 'wp is not defined' in the browser console, your root cause is different and that fix will not apply.
Yes. The notes come from problems met in live systems, so the section grows as new problems get solved.
Yes. The problems covered here fall directly within scope. Describe the symptom you are seeing and get in touch; diagnosis is usually quick, because the symptoms are quite distinctive.