I am in the process of implementing an API Gateway as a point of access to several existing APIs that run as microservices.
Each microservice API is defined in OpenAPI and runs an instance of swagger-ui to document and expose endpoints. Everything is written in Ruby on Rails as separate API-only projects.
I'm looking at Kong or Tyk in the role of API Gateway. Is it possible with either project to run swagger-ui on the gateway to document available routes through the gateway and to allow authenticated users to try the various endpoints exposed by the different services in one place rather than per-service? If not, does either project provide such an interface in any form?
Yes for Tyk. You can design with Swagger-UI and import the generated OpenAPI specification into Tyk gateway for the routes. The gateway immediately populates the routes and start proxying API traffic. You can then choose to further enforce authentication or add middleware to these routes.
https://tyk.io/docs/getting-started/using-oas-definitions/create-an-oas-api/
For consumption, you can also publish APIs on to Tyk's developer portal with OpenAPI documentation.