ServiceStack supports of course the most-used two webservices formats: XML and JSON. By default, the ServiceStack.Text serializer is used for JSON - it's the fastest JSON serializer for .Net!

ServiceStack also provides a format called JSV:

JSV is a text-based format that is optimized for both size and speed.

In many ways it is similar to JavaScript, e.g. any List, Array, Collection of ints, longs, etc are stored in exactly the same way, i.e: [1,2,3,4,5]

Any IDictionary is serialized like JavaScript, i.e: {A:1,B:2,C:3,D:4}

Which also happens to be the same as C# POCO class with the values

new MyClass { A=1, B=2, C=3, D=4 }

{A:1,B:2,C:3,D:4}

JSV is white-space significant, which means normal string values can be serialized without quotes, e.g:

new MyClass { Foo="Bar", Greet="Hello World!"} is serialized as:

{Foo:Bar,Greet:Hello World!}

Any string with any of the following characters: []{}," is escaped using CSV-style escaping where the value is wrapped in double quotes, e.g:

new MyClass { Name = "Me, Junior" } is serialized as:

{Name:"Me, Junior"}

A value with a double-quote is escaped with another double quote e.g:

new MyClass { Size = "2\" x 1\"" } is serialized as:

{Size:"2"" x 1"""}