Okyline is a declarative, example-driven language for describing and validating JSON data.
An Okyline schema is a real example of data, enriched with built-in constraints. It remains readable while serving as an enforceable contract. A single Okyline contract expresses both the data structure (types, presence, enumerations, lengths, models, key uniqueness) and its cross-field business invariants (consistency, conditional requirements, exact decimal arithmetic, and ordering constraints) through a pure and deterministic expression language. It also defines version management and cross-schema composition (semantic versions, dependencies, imports, visibility), so that contracts can be shared and evolved across teams.
This repository hosts the official Okyline Language Specification (version 1.8.0, September 2026).
These are the official reference documents for Okyline 1.8.0:
- Core Specification - Okyline-Core-Language-Specification-v1.8.0.md
- Annex C - Expression Language - Okyline-Annex-C-Expression-language-v1.8.0.md
- Annex D - Internal Schema References - Okyline-Annex-D-Internal-References-v1.8.0.md
- Annex E - External Imports and Versioning - Okyline-Annex-E-External-Imports-v1.8.0.md
- Annex F - Virtual Fields - Okyline-Annex-F-Virtual-Fields-v1.8.0.md
Quick references and user guides are companion (non-normative) material, published on the documentation hub: https://community.okyline.design-hub.okyline.io/
The Okyline Language Specification is published under:
Creative Commons Attribution-ShareAlike 4.0 International (CC BY-SA 4.0)
https://creativecommons.org/licenses/by-sa/4.0/
Okyline Studio Free fully implements the Okyline 1.8.0 specification and provides:
- Visual Okyline schema editor
- Instant documentation generation
- Automatic JSON Schema transpilation
- Interactive JSON validation against a selected Okyline schema
Try it online:
https://community.studio.okyline.io/
All free Okyline resources (guides, documentation, studio) are available at:
https://community.okyline.design-hub.okyline.io/
https://www.akwatype.io
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