Spectral
A flexible JSON/YAML linter for creating automated style guides
...Spectral is open-source but is also baked into Stoplight, with extensions for VS Code and other integration options, giving you real-time feedback wherever you design APIs. Spectral can be used as a generic ruleset engine on any JSON or YAML data but was built with OpenAPI, AsyncAPI, and JSON Schema in mind. Use Spectral rules to target API descriptions for quality improvement or enforce API Style Guide rules, such as naming conventions for OpenAPI models or prohibiting integers in URLs.