Content Negotiation in ASP.NET Web API

Content negotiation is the process that describe the in which format the response is provide by Web API according to the request.

The HTTP specification (RFC 2616) defines content negotiation as “the process of selecting the best representation for a given response when there are multiple representations available.” The primary mechanism for content negotiation in HTTP are these request headers:

1. Accept:Which media types are acceptable for the response, such as “application/json,” “application/xml,” or a custom media type such as "application/vnd.example+xml"
2. Accept-Charset: Which character sets are acceptable, such as UTF-8 or ISO 8859-1.
3. Accept-Encoding: Which content encodings are acceptable, such as gzip.
4. Accept-Language: The preferred natural language, such as “en-us”.

The server looks for above HTTP request details.