ddd-playbook

Ubiquitous language is shared vocabulary between developers and stakeholders. Start by describing your domain in plain terms, define a single bounded context (the Todo Management boundary), identify the core aggregate, and list its invariants—the rules that must always hold true.

Invariants are business rules that must remain valid at all times. This guidance limits aggregates to up to five invariants to keep the domain model minimal and maintainable. Examples: a todo cannot be completed without a title, or a task cannot exist in two states simultaneously.

Propose a minimal aggregate with clearly defined invariants, then map each capability to a use-case contract. Update your domain model, invariants, and contracts iteratively as you discover new requirements. Keep the aggregate boundary tight to avoid over-modeling.

Yes. Domain-driven design applies directly to todo management. This guidance walks you through establishing a Todo Management bounded context, defining aggregates with invariants, and aligning use-case contracts to your actual capabilities and business rules.

Domain-driven design focuses on modeling the business domain first—its language, rules, and boundaries—before technology. Unlike layered or service-oriented approaches, DDD ensures your code reflects how stakeholders actually think about todos and their management.

No. This guidance deliberately avoids advanced patterns unless you ask for them. Start with one bounded context, a minimal aggregate, and up to five invariants. Master the fundamentals—ubiquitous language, aggregate design, and invariant enforcement—before exploring event sourcing or sagas.