In the Resource Linkage section of json:api specification I found that you can fetch a related resource object with a url like this, http://example.com/articles/1/author, making reference to "the author of the article with id 1".
In the site complete example we can see that the author has id 9.
// ...
{
"type": "articles",
"id": "1",
"attributes": {
"title": "Rails is Omakase"
},
"relationships": {
"author": {
"links": {
"self": "http://example.com/articles/1/relationships/author",
"related": "http://example.com/articles/1/author"
},
"data": { "type": "people", "id": "9" }
}
},
"links": {
"self": "http://example.com/articles/1"
}
}
// ...
So, if I understood it, I would be able to request the same resource with two different urls:
http://example.com/articles/1/author
http://example.com/authors/9
Is this ok?
Wouldn't this be considerated duplicate content?
The article you have linked talks about duplicated content in the context of a website. JSON:API specification is about an API. A website is typically meant to be read and consumed by humans. An API is meant for programs to be consumed. The SEO concerns raised by that article are not applyable to an API cause search engines like Google does not care about API responses. They may care about the website build based on the data fetch of that API. That website should have a unique URL or a rel="canonical" attribute.