We are the developers behind Fusio which is an open source API management system. We wanted to build an SDK generator for different languages, which builds an SDK based on the available schema. During this we have experienced the limitations of JSON Schema for code generators. Because of this we have started to develop TypeSchema. A JSON format which can be easily transformed into code and also other specification formats. This means we can also reuse any TypeSchema at an OpenAPI specification.
We envision a future where the code generation ecosystem just works. That means a user gets an OpenAPI document and he is able to use this document to generate high quality code for either client or server implementations.
The complete website is also opensource, you can check out our repository and take a look at the www folder, there is all code related to the website placed. If you want to take a look at the code generator you can check out the schema repository.
You can contact us directly in case you have a question regarding the project, or you can also take a look at our repository.
In our mission to improve code generation we write articles explaining our thoughts and background regarding TypeSchema and the hole API and code generation ecosystem. If you are interested you can take a look at the following articles:
TypeSchema is not designed to validate JSON data. This means our goal is not to introduce many keywords to be able to validate all possible JSON data. Instead we focusing on describing data in an elegant and simple way.
For code generators it is difficult to work with JSON Schema since it is
designed to validate JSON data. In JSON Schema you dont need to provide any
keywords i.e. {} is a valid JSON Schema which basically allows
every value and the defined keywords are applied based on the actual data. This
means you can interpret a schema only if you have also the actual data. A
code generator on the other hand needs to determine a concrete type of a
schema without the actual data.
JSON Schema has many keywords which contain logic like
dependencies, not, if/then/else which
are basically not needed for code generators and really complicates building
them. We have also explained some pitfalls in our
migration document.
TypeSchema does not work with JSON pointer. In TypeSchema you reference
every type simply by the name i.e. Student. In JSON Schema you
need to provide the path i.e. #/definitions/Student to the schema.
In TypeSchema you can also reference only local types. If you want to import a
remote schema you need to explicit declare it via $import.