Give each bounded context its own model and words

How to do it

One shared Customer type for billing, support and shipping grows a field for every team and breaks all of them on each change. In billing a customer has a VAT number and a payment method. In shipping it has an address. Let each context hold its own type, named with the words its business people use, and link them by ID. Write each context's terms in a short glossary file next to its code. This builds on Group code by feature and Keep internals private.

Examples

JavaScript example

// .dependency-cruiser.cjs
module.exports = {
  forbidden: [{
    name: 'contexts-use-public-entry-only',
    severity: 'error',
    from: { path: '^src/contexts/([^/]+)/' },
    to: { path: '^src/contexts/([^/]+)/(?!index\\.ts$)', pathNot: '^src/contexts/$1/' },
  }],
};

Java example

@ArchTest
static final ArchRule shippingUsesBillingApiOnly = noClasses()
    .that().resideInAPackage("com.example.shipping..")
    .should().dependOnClassesThat().resideInAPackage("com.example.billing.internal..");

How to check

An import rule, such as dependency-cruiser, import-linter or ArchUnit, fails the build when one context imports another context's internal files. Each context folder holds a glossary file.

Sources

• .NET architecture guide on designing a domain model
• .NET architectural principles on bounded contexts

Related rules

• ARC-65 Group code by feature in Clean code and architecture
• ARC-39 Keep internals private in Clean code and architecture