– Booking is modelled as an independent domain, not as an integration with one specific API. – DDD and SDD first, code second, so the architecture never depends on a provider. – Provider keys stay on the server and contracts plug in as modules, so new calendars are easy to add.

– Most WordPress projects fail not because of PHP, but because of language. – A shared domain language and bounded contexts keep the architecture from falling apart. – A context map turns plugin chaos into a scalable platform.

– Developers, stakeholders and the product owner share one vocabulary. – A single language reduces confusion across teams and simplifies maintenance. – Names in code reflect business concepts, not technical abstractions.

– When there are many actively used plugins, coordinating between them becomes the real pain. – 4WP.dev offers a modular framework for interconnected plugins. – Focus on Gutenberg blocks and built-in SEO in every module.

– Filters do not just change data — they also control system behaviour. – Boolean filters like `send_email_change_email` during a B2B migration prevent mass emails. – A scoped filter override is an architectural decision that depends on context (CRM sync).