Elasticsearch.Net maps all the Elasticsearch API endpoints to methods. The reason it can do this is because all these methods are generated from the official client REST specification. This specification documents all the URL’s (paths and querystrings) but does not map any of the API request and response bodies.

client.GetSource("myindex","mytype","1",qs=>qs
    .Routing("routingvalue")
);

Which will do a GET request on /myindex/mytype/1/_source?routing=routingvalue. All the methods and arguments are fully documented based on the documentation of the specification.

As you can see, Elasticsearch.Net also strongly types the querystring parameters it knows exist on an endpoint with full Intellisense documentation. Unknown querystring parameters can still be added:

client.GetSource("myindex","mytype","1",qs=>qs
    .Routing("routingvalue")
    .Add("key","value")
);

The querystring parameter is always optional.

Providing a Request Bodyedit

Some endpoints need a request body which can be passed in a couple of ways

Stringedit

var myJson = @"{ ""hello"" : ""world"" }";

client.Index("myindex","mytype","1", myJson);

This will call POST on /myindex/mytype/1 with the provided string myJson passed verbatim as the request body

(Anonymous) Objectedit

var myJson = new { hello = "world" };
client.Index("myindex","mytype","1", myJson);

This will call POST on /myindex/mytype/1 where myJson will be serialized by the registered ISerializer

IEnumerable<object>edit

Some API endpoints in Elasticsearch follow a strict special json format.

line_of_json_with_no_enters \n
json_payload_with_enters
line_of_json_with_no_enters \n
json_payload_with_enters
line_of_json_with_no_enters \n
json_payload_with_enters

Examples of such endpoints are the bulk api. In Elasticsearch.Net you can call these with

var bulk = new object[]
{
    new { index = new { _index = "test", _type="type", _id = "1"  }},
    new { name = "my object's name" }
};

client.Bulk(bulk);

Elasticsearch.Net will know not to serialize the passed object as [] but instead serialize each item seperately and join them up with \n. No request in Elasticsearch expects an array as the root object for the request.