What is "Standard Specification Language"?

[antoneskov]

"API Design/Design Principles/API First", first bullet. What is a "standard specification language"? Open API Specification? Isn't it too much REST specific? What about Non-REST APIs?

[oyron]

There are a number of standard specification languages:

REST: OpenAPI spec.
Async/event-based protocols like AMQP, MQTT, WebSocets, etc: AsyncAPI - https://www.asyncapi.com/
GraphQL has the spec built in: https://graphql.github.io/graphql-spec/
gRPC also has the spec built in - through it's usage of protocol buffers and the proto format: https://developers.google.com/protocol-buffers/docs/proto3