diff --git a/src/Internal/Api/WhoAmI/Api.elm b/src/Internal/Api/WhoAmI/Api.elm
new file mode 100644
index 0000000..0be3a1b
--- /dev/null
+++ b/src/Internal/Api/WhoAmI/Api.elm
@@ -0,0 +1,47 @@
+module Internal.Api.WhoAmI.Api exposing (..)
+
+import Internal.Api.Request as R
+import Internal.Api.WhoAmI.V1.SpecObjects as SO1
+import Internal.Api.WhoAmI.V2.SpecObjects as SO2
+import Internal.Api.WhoAmI.V3.SpecObjects as SO3
+import Internal.Tools.Context exposing (Context)
+import Internal.Tools.Exceptions as X
+import Internal.Tools.SpecEnums as Enums
+import Task exposing (Task)
+
+
+type alias WhoAmIInputV1 =
+    ()
+
+
+type alias WhoAmIOutputV1 =
+    SO1.WhoAmIResponse
+
+
+type alias WhoAmIOutputV2 =
+    SO2.WhoAmIResponse
+
+
+type alias WhoAmIOutputV3 =
+    SO3.WhoAmIResponse
+
+
+whoAmIV1 : WhoAmIInputV1 -> Context { a | accessToken : (), baseUrl : () } -> Task X.Error WhoAmIOutputV1
+whoAmIV1 _ =
+    R.callApi "GET" "/_matrix/client/r0/account/whoami"
+        >> R.withAttributes [ R.accessToken ]
+        >> R.toTask SO1.whoAmIResponseDecoder
+
+
+whoAmIV2 : WhoAmIInputV1 -> Context { a | accessToken : (), baseUrl : () } -> Task X.Error WhoAmIOutputV2
+whoAmIV2 _ =
+    R.callApi "GET" "/_matrix/client/v3/account/whoami"
+        >> R.withAttributes [ R.accessToken ]
+        >> R.toTask SO2.whoAmIResponseDecoder
+
+
+whoAmIV3 : WhoAmIInputV1 -> Context { a | accessToken : (), baseUrl : () } -> Task X.Error WhoAmIOutputV3
+whoAmIV3 _ =
+    R.callApi "GET" "/_matrix/client/v3/account/whoami"
+        >> R.withAttributes [ R.accessToken ]
+        >> R.toTask SO3.whoAmIResponseDecoder
diff --git a/src/Internal/Api/WhoAmI/Main.elm b/src/Internal/Api/WhoAmI/Main.elm
new file mode 100644
index 0000000..0f65309
--- /dev/null
+++ b/src/Internal/Api/WhoAmI/Main.elm
@@ -0,0 +1,49 @@
+module Internal.Api.WhoAmI.Main exposing (..)
+
+import Internal.Api.WhoAmI.Api as Api
+import Internal.Api.WhoAmI.V2.Upcast as U2
+import Internal.Api.WhoAmI.V3.Upcast as U3
+import Internal.Tools.Context as Context exposing (Context, VBA)
+import Internal.Tools.Exceptions as X
+import Internal.Tools.VersionControl as VC
+import Task exposing (Task)
+
+
+whoAmI : Context (VBA a) -> WhoAmIInput -> Task X.Error WhoAmIOutput
+whoAmI context input =
+    VC.withBottomLayer
+        { current = Api.whoAmIV1
+        , version = "r0.3.0"
+        }
+        |> VC.sameForVersion "r0.4.0"
+        |> VC.sameForVersion "r0.5.0"
+        |> VC.sameForVersion "r0.6.0"
+        |> VC.sameForVersion "r0.6.1"
+        |> VC.addMiddleLayer
+            { downcast = identity
+            , current = Api.whoAmIV2
+            , upcast = \f c -> Task.map U2.upcastWhoAmIResponse (f c)
+            , version = "v1.1"
+            }
+        |> VC.addMiddleLayer
+            { downcast = identity
+            , current = Api.whoAmIV3
+            , upcast = \f c -> Task.map U3.upcastWhoAmIResponse (f c)
+            , version = "v1.2"
+            }
+        |> VC.sameForVersion "v1.3"
+        |> VC.sameForVersion "v1.4"
+        |> VC.sameForVersion "v1.5"
+        |> VC.sameForVersion "v1.6"
+        |> VC.mostRecentFromVersionList (Context.getVersions context)
+        |> Maybe.withDefault (always <| always <| Task.fail X.UnsupportedSpecVersion)
+        |> (|>) input
+        |> (|>) context
+
+
+type alias WhoAmIInput =
+    Api.WhoAmIInputV1
+
+
+type alias WhoAmIOutput =
+    Api.WhoAmIOutputV3
diff --git a/src/Internal/Api/WhoAmI/V1/SpecObjects.elm b/src/Internal/Api/WhoAmI/V1/SpecObjects.elm
new file mode 100644
index 0000000..547686b
--- /dev/null
+++ b/src/Internal/Api/WhoAmI/V1/SpecObjects.elm
@@ -0,0 +1,38 @@
+module Internal.Api.WhoAmI.V1.SpecObjects exposing
+    ( WhoAmIResponse
+    , encodeWhoAmIResponse
+    , whoAmIResponseDecoder
+    )
+
+{-| Automatically generated 'SpecObjects'
+
+Last generated at Unix time 1679665928
+
+-}
+
+import Internal.Tools.EncodeExtra exposing (maybeObject)
+import Json.Decode as D
+import Json.Encode as E
+
+
+{-| Response telling the user to whom their access token belongs.
+-}
+type alias WhoAmIResponse =
+    { userId : String
+    }
+
+
+encodeWhoAmIResponse : WhoAmIResponse -> E.Value
+encodeWhoAmIResponse data =
+    maybeObject
+        [ ( "user_id", Just <| E.string data.userId )
+        ]
+
+
+whoAmIResponseDecoder : D.Decoder WhoAmIResponse
+whoAmIResponseDecoder =
+    D.map
+        (\a ->
+            { userId = a }
+        )
+        (D.field "user_id" D.string)
diff --git a/src/Internal/Api/WhoAmI/V1/SpecObjects.yaml b/src/Internal/Api/WhoAmI/V1/SpecObjects.yaml
new file mode 100644
index 0000000..68026f0
--- /dev/null
+++ b/src/Internal/Api/WhoAmI/V1/SpecObjects.yaml
@@ -0,0 +1,9 @@
+version: v1
+name: SpecObjects
+objects:
+  WhoAmIResponse:
+    description: Response telling the user to whom their access token belongs.
+    fields:
+      user_id:
+        type: string
+        required: true
diff --git a/src/Internal/Api/WhoAmI/V2/SpecObjects.elm b/src/Internal/Api/WhoAmI/V2/SpecObjects.elm
new file mode 100644
index 0000000..b25fd3d
--- /dev/null
+++ b/src/Internal/Api/WhoAmI/V2/SpecObjects.elm
@@ -0,0 +1,42 @@
+module Internal.Api.WhoAmI.V2.SpecObjects exposing
+    ( WhoAmIResponse
+    , encodeWhoAmIResponse
+    , whoAmIResponseDecoder
+    )
+
+{-| Automatically generated 'SpecObjects'
+
+Last generated at Unix time 1679665928
+
+-}
+
+import Internal.Tools.DecodeExtra exposing (opField)
+import Internal.Tools.EncodeExtra exposing (maybeObject)
+import Json.Decode as D
+import Json.Encode as E
+
+
+{-| Response telling the user to whom their access token belongs.
+-}
+type alias WhoAmIResponse =
+    { deviceId : Maybe String
+    , userId : String
+    }
+
+
+encodeWhoAmIResponse : WhoAmIResponse -> E.Value
+encodeWhoAmIResponse data =
+    maybeObject
+        [ ( "device_id", Maybe.map E.string data.deviceId )
+        , ( "user_id", Just <| E.string data.userId )
+        ]
+
+
+whoAmIResponseDecoder : D.Decoder WhoAmIResponse
+whoAmIResponseDecoder =
+    D.map2
+        (\a b ->
+            { deviceId = a, userId = b }
+        )
+        (opField "device_id" D.string)
+        (D.field "user_id" D.string)
diff --git a/src/Internal/Api/WhoAmI/V2/SpecObjects.yaml b/src/Internal/Api/WhoAmI/V2/SpecObjects.yaml
new file mode 100644
index 0000000..20997dc
--- /dev/null
+++ b/src/Internal/Api/WhoAmI/V2/SpecObjects.yaml
@@ -0,0 +1,12 @@
+version: v1
+name: SpecObjects
+objects:
+  WhoAmIResponse:
+    description: Response telling the user to whom their access token belongs.
+    fields:
+      user_id:
+        type: string
+        required: true
+      device_id:
+        type: string
+        required: false
diff --git a/src/Internal/Api/WhoAmI/V2/Upcast.elm b/src/Internal/Api/WhoAmI/V2/Upcast.elm
new file mode 100644
index 0000000..ae84171
--- /dev/null
+++ b/src/Internal/Api/WhoAmI/V2/Upcast.elm
@@ -0,0 +1,9 @@
+module Internal.Api.WhoAmI.V2.Upcast exposing (..)
+
+import Internal.Api.WhoAmI.V1.SpecObjects as PO
+import Internal.Api.WhoAmI.V2.SpecObjects as SO
+
+
+upcastWhoAmIResponse : PO.WhoAmIResponse -> SO.WhoAmIResponse
+upcastWhoAmIResponse old =
+    { userId = old.userId, deviceId = Nothing }
diff --git a/src/Internal/Api/WhoAmI/V3/SpecObjects.elm b/src/Internal/Api/WhoAmI/V3/SpecObjects.elm
new file mode 100644
index 0000000..8c23bd5
--- /dev/null
+++ b/src/Internal/Api/WhoAmI/V3/SpecObjects.elm
@@ -0,0 +1,45 @@
+module Internal.Api.WhoAmI.V3.SpecObjects exposing
+    ( WhoAmIResponse
+    , encodeWhoAmIResponse
+    , whoAmIResponseDecoder
+    )
+
+{-| Automatically generated 'SpecObjects'
+
+Last generated at Unix time 1679665928
+
+-}
+
+import Internal.Tools.DecodeExtra exposing (opField, opFieldWithDefault)
+import Internal.Tools.EncodeExtra exposing (maybeObject)
+import Json.Decode as D
+import Json.Encode as E
+
+
+{-| Response telling the user to whom their access token belongs.
+-}
+type alias WhoAmIResponse =
+    { deviceId : Maybe String
+    , isGuest : Bool
+    , userId : String
+    }
+
+
+encodeWhoAmIResponse : WhoAmIResponse -> E.Value
+encodeWhoAmIResponse data =
+    maybeObject
+        [ ( "device_id", Maybe.map E.string data.deviceId )
+        , ( "is_guest", Just <| E.bool data.isGuest )
+        , ( "user_id", Just <| E.string data.userId )
+        ]
+
+
+whoAmIResponseDecoder : D.Decoder WhoAmIResponse
+whoAmIResponseDecoder =
+    D.map3
+        (\a b c ->
+            { deviceId = a, isGuest = b, userId = c }
+        )
+        (opField "device_id" D.string)
+        (opFieldWithDefault "is_guest" False D.bool)
+        (D.field "user_id" D.string)
diff --git a/src/Internal/Api/WhoAmI/V3/SpecObjects.yaml b/src/Internal/Api/WhoAmI/V3/SpecObjects.yaml
new file mode 100644
index 0000000..814e4bb
--- /dev/null
+++ b/src/Internal/Api/WhoAmI/V3/SpecObjects.yaml
@@ -0,0 +1,16 @@
+version: v1
+name: SpecObjects
+objects:
+  WhoAmIResponse:
+    description: Response telling the user to whom their access token belongs.
+    fields:
+      user_id:
+        type: string
+        required: true
+      device_id:
+        type: string
+        required: false
+      is_guest:
+        type: bool
+        required: false
+        default: false
diff --git a/src/Internal/Api/WhoAmI/V3/Upcast.elm b/src/Internal/Api/WhoAmI/V3/Upcast.elm
new file mode 100644
index 0000000..6b921a6
--- /dev/null
+++ b/src/Internal/Api/WhoAmI/V3/Upcast.elm
@@ -0,0 +1,9 @@
+module Internal.Api.WhoAmI.V3.Upcast exposing (..)
+
+import Internal.Api.WhoAmI.V2.SpecObjects as PO
+import Internal.Api.WhoAmI.V3.SpecObjects as SO
+
+
+upcastWhoAmIResponse : PO.WhoAmIResponse -> SO.WhoAmIResponse
+upcastWhoAmIResponse old =
+    { deviceId = old.deviceId, isGuest = False, userId = old.userId }