Product Specification
A written description of how a product behaves, feature by feature, scenario by scenario. Distinct from a technical spec, which describes implementation.
A product specification answers the question “how does this product behave?” without requiring the reader to understand how it's built. It describes behaviour in terms of what a user sees, what they do, and how the product responds, not classes, functions, or database schemas.
Traditional product specs are written once, before development, and then abandoned. They describe what was planned, not what shipped. A spec read from the code is different: it reflects the product as it shipped, and updates on every release.
The audience matters. A product spec is read by product managers, customer success teams, engineering managers, and stakeholders. It isn't read by compilers. That's why the format matters: structured enough to be unambiguous, plain enough that nobody needs a glossary.
Related terms
- CONCEPT
Living Documentation
The mechanism behind product observability: a spec derived from the code rather than written separately, so it moves with the product instead of falling out of sync.
- SPEC
Scenario
A single plain-language description of how a product behaves in a specific situation. The atomic unit of a Specsight spec.
- SPEC
Feature
A logical grouping of scenarios that represents a meaningful unit of the product, like “Document Upload” or “User Authentication.” features form the structure of a Specsight spec.