[dcre]

You said it yourself — the “official” generator is awful and very hard to modify or extend (well, you didn’t say that, but I’m saying it) and while there are many alternatives, they’re not always easy to find. I had some success with swagger-typescript-api[1], but eventually got tired of it and wrote my own generator. Despite looking around quite a bit at what’s available, I never heard of openapi-codegen, which looks quite good.

I think it’s a pretty big problem for many devs that so many of the options are mediocre and they’re quite difficult to evaluate unless you have a lot of experience, and even then it takes a lot of time.

[1]: https://github.com/acacode/swagger-typescript-api

[handrews]

Technically, there isn't an "official" OpenAPI 3.x tool of any sort. SmartBear/Swagger is no more official than any other vendor with 3.0+ (obviously it's different for the versions named "Swagger"!). I am working on an official parser/linter (oascomply) on a contract for the OpenAPI Initiative to set a baseline to help tool developers implement consistent support for the spec. However, this is more about the parts of OAS outside of the Schema Object.