Architecture documents, decision records, API specs and data models.
Solution Architecture Document
The structure of a system, the constraints that shaped it, and the trade-offs accepted.
Architecture Decision Record
One decision, its context, the options rejected, and what it costs — in under a page.
API Specification
The contract between two teams: resources, errors, versioning and what happens when it breaks.
Data Model Document
Entities, relationships, classification and retention — the parts of the schema that outlive the code.
Technical Design Document
How one component will actually be built — enough detail to review the idea before the code exists.