diff --git a/Sources/Filters/KeyNameFilter.swift b/Sources/Filters/KeyNameFilter.swift
index b04e634..554033b 100644
--- a/Sources/Filters/KeyNameFilter.swift
+++ b/Sources/Filters/KeyNameFilter.swift
@@ -8,8 +8,8 @@ public struct KeyNameFilter {
     // MARK: Initialisers
     
     public init(
-        key: String?,
-        name: String?
+        key: String? = nil,
+        name: String? = nil
     ) {
         self.key = key
         self.name = name
diff --git a/Sources/Protocols/Service.swift b/Sources/Protocols/Service.swift
new file mode 100644
index 0000000..ab6fe6d
--- /dev/null
+++ b/Sources/Protocols/Service.swift
@@ -0,0 +1,14 @@
+import Foundation
+
+protocol Service {
+    
+    // MARK:  Functions
+    
+    func amiibos(filter: AmiiboFilter) async throws -> [Amiibo]
+    func amiiboSeries(filter: AmiiboSeriesFilter) async throws -> [AmiiboSeries]
+    func amiiboTypes(filter: AmiiboTypeFilter) async throws -> [AmiiboType]
+    func gameSeries(filter: GameSeriesFilter) async throws -> [GameSeries]
+    func characters(filter: CharacterFilter) async throws -> [Character]
+    func lastUpdated() async throws -> Date
+
+}