Domain-Driven Design in PHP 8.5: Building Maintainable and Scalable Applications

You open a controller and find two hundred lines staring back at you. A status check here, a total recalculated there, a rule you swear you've seen enforced somewhere else too - except this time it's spelled slightly differently. You didn't write this mess on purpose. Nobody does. It just happens, one deadline at a time, until the business logic your whole application depends on is scattered across a dozen files with no single place that actually owns it.

What if it didn't have to be this way?

What if an Order object simply refused to ship itself before it was paid - not because a service class remembered to check, but because it was never able to break that rule in the first place? That's the shift this book walks you through, chapter by chapter, using nothing but PHP you can write starting today.

• Why DDD, why now - what it actually fixes, and what it honestly doesn't
• PHP 8.5 as your foundation - readonly properties, enums, property hooks, and a type system built for modeling
• Entities and value objects - identity, immutability, and self-validation done right
• Aggregates - enforcing invariants without building a god object
• Domain services, repositories, and factories - the supporting cast, wired together with dependency injection
• Bounded contexts - taming a large application without losing your mind
• Application layer and CQRS - commands, queries, and events that don't fight each other
• Persistence, testing, and long-term maintenance - because a model that only works on day one isn't a model at all

You're a PHP developer, comfortable with objects and classes, who has felt that specific ache of a codebase where nobody's quite sure where a rule lives anymore. You don't need prior DDD experience - just a willingness to see PHP differently.

Your next feature request is coming, whether your codebase is ready or not. Every day you keep writing anemic models is a day the debt compounds. Open Chapter 1. Start where the problem actually starts - and build something your team will still trust a year from now.