diff --git a/JSONAPI.playground/Pages/Full Client & Server Example.xcplaygroundpage/Contents.swift b/JSONAPI.playground/Pages/Full Client & Server Example.xcplaygroundpage/Contents.swift
index eabd561..96a7168 100644
--- a/JSONAPI.playground/Pages/Full Client & Server Example.xcplaygroundpage/Contents.swift	
+++ b/JSONAPI.playground/Pages/Full Client & Server Example.xcplaygroundpage/Contents.swift	
@@ -37,7 +37,7 @@ typealias ToManyRelationship<Entity: Relatable> = JSONAPI.ToManyRelationship<Ent
 // JSON:API Documents for this particular API to have Metadata, Links,
 // useful Errors, or an APIDescription (The *SPEC* calls this
 // "API Description" the "JSON:API Object").
-typealias Document<PrimaryResourceBody: JSONAPI.ResourceBody, IncludeType: JSONAPI.Include> = JSONAPI.Document<PrimaryResourceBody, NoMetadata, NoLinks, IncludeType, NoAPIDescription, BasicJSONAPIError<String>>
+typealias Document<PrimaryResourceBody: JSONAPI.EncodableResourceBody, IncludeType: JSONAPI.Include> = JSONAPI.Document<PrimaryResourceBody, NoMetadata, NoLinks, IncludeType, NoAPIDescription, BasicJSONAPIError<String>>
 
 // MARK: Entity Definitions
 
diff --git a/JSONAPI.playground/Pages/Usage.xcplaygroundpage/Contents.swift b/JSONAPI.playground/Pages/Usage.xcplaygroundpage/Contents.swift
index e5434e5..5917bef 100644
--- a/JSONAPI.playground/Pages/Usage.xcplaygroundpage/Contents.swift
+++ b/JSONAPI.playground/Pages/Usage.xcplaygroundpage/Contents.swift
@@ -64,11 +64,11 @@ if case let .data(bodyData) = peopleResponse.body {
 
 // MARK: - Work in the abstract
 print("-----")
-func process<T: JSONAPIDocument>(document: T) {
-	guard case let .data(body) = document.body else {
+func process<T: CodableJSONAPIDocument>(document: T) {
+    guard let body = document.body.data else {
 		return
 	}
-	let x: T.Body.Data = body
+	let x: T.BodyData = body
 }
 process(document: peopleResponse)