Specif

Specif is a lightweight, text-based data specification language designed to describe data models, interfaces, and contracts between software components. It emphasizes readability for humans and machine parseability, aiming to complement existing schema languages with a concise syntax.

Its design centers on simple block-like definitions for types and services. Supported features include primitive and composite types, optional fields, default values, and constraints such as ranges or patterns. References to other types enable modular schemas, and versioning facilitates evolution without breaking changes. Specif documents are typically language-agnostic and can be used to generate code, documentation, or validation strategies.

An example specification might define a Person type and a UserService interface. For instance: type Person { name: string; age: int [optional, 0-120]; email: string [optional] } service UserService { getUser(id: string): Person }

History and usage: Specif emerged in the early 2010s through community-driven projects, later gaining traction in teams seeking lightweight API contracts. It remains a niche format, with a small ecosystem of parsers and code generators. Critics cite limited tooling and ecosystem as drawbacks when compared with more widespread formats such as OpenAPI or JSON Schema.

See also: OpenAPI, JSON Schema, API contract, Interface Definition Language.