diff --git a/src/Internal/Api/Credentials.elm b/src/Internal/Api/Credentials.elm
index c6b54c9..7bd89c2 100644
--- a/src/Internal/Api/Credentials.elm
+++ b/src/Internal/Api/Credentials.elm
@@ -24,6 +24,13 @@ accessToken (Credentials { access }) =
     access
 
 
+{-| Retrieves the access token type without the access token value in case the value is no longer valid.
+-}
+refreshedAccessToken : Credentials -> AccessToken
+refreshedAccessToken (Credentials { access }) =
+    Login.removeToken access
+
+
 {-| Add a new access token to the `Credentials` type.
 -}
 addToken : String -> Credentials -> Credentials
diff --git a/src/Internal/Api/GetEvent/Api.elm b/src/Internal/Api/GetEvent/Api.elm
index d044ffd..ac9c1dd 100644
--- a/src/Internal/Api/GetEvent/Api.elm
+++ b/src/Internal/Api/GetEvent/Api.elm
@@ -2,14 +2,13 @@ module Internal.Api.GetEvent.Api exposing (..)
 
 import Internal.Api.GetEvent.V1.SpecObjects as SO1
 import Internal.Api.Request as R
-import Internal.Tools.Context exposing (Context)
+import Internal.Tools.Context as Context exposing (Context)
 import Internal.Tools.Exceptions as X
 import Task exposing (Task)
 
 
 type alias GetEventInputV1 =
-    { eventId : String
-    , roomId : String
+    { roomId : String
     }
 
 
@@ -17,12 +16,13 @@ type alias GetEventOutputV1 =
     SO1.ClientEvent
 
 
-getEventInputV1 : GetEventInputV1 -> Context { a | accessToken : (), baseUrl : () } -> Task X.Error GetEventOutputV1
-getEventInputV1 data =
-    R.callApi "GET" "/_matrix/client/v3/rooms/{roomId}/event/{eventId}"
-        >> R.withAttributes
+getEventInputV1 : GetEventInputV1 -> Context { a | accessToken : (), baseUrl : (), sentEvent : () } -> Task X.Error GetEventOutputV1
+getEventInputV1 data context =
+    context
+        |> R.callApi "GET" "/_matrix/client/v3/rooms/{roomId}/event/{eventId}"
+        |> R.withAttributes
             [ R.accessToken
-            , R.replaceInUrl "eventId" data.eventId
+            , R.replaceInUrl "eventId" (Context.getSentEvent context)
             , R.replaceInUrl "roomId" data.roomId
             ]
-        >> R.toTask SO1.clientEventDecoder
+        |> R.toTask SO1.clientEventDecoder
diff --git a/src/Internal/Api/GetEvent/Main.elm b/src/Internal/Api/GetEvent/Main.elm
index 3c5c019..2585239 100644
--- a/src/Internal/Api/GetEvent/Main.elm
+++ b/src/Internal/Api/GetEvent/Main.elm
@@ -7,7 +7,7 @@ import Internal.Tools.VersionControl as VC
 import Task exposing (Task)
 
 
-getEvent : Context (VBA a) -> EventInput -> Task X.Error EventOutput
+getEvent : Context (VBA { a | sentEvent : () }) -> EventInput -> Task X.Error EventOutput
 getEvent context input =
     VC.withBottomLayer
         { current = Api.getEventInputV1
diff --git a/src/Internal/Api/Request.elm b/src/Internal/Api/Request.elm
index a110ab8..742800d 100644
--- a/src/Internal/Api/Request.elm
+++ b/src/Internal/Api/Request.elm
@@ -5,9 +5,7 @@ import Internal.Tools.Context as Context exposing (Context)
 import Internal.Tools.Exceptions as X
 import Json.Decode as D
 import Json.Encode as E
-import Process
 import Task exposing (Task)
-import Time
 import Url
 import Url.Builder as UrlBuilder
 
diff --git a/src/Internal/Api/Task.elm b/src/Internal/Api/Task.elm
index f5ed883..bece683 100644
--- a/src/Internal/Api/Task.elm
+++ b/src/Internal/Api/Task.elm
@@ -5,7 +5,7 @@ module Internal.Api.Task exposing (..)
 
 import Hash
 import Internal.Api.Chain as Chain
-import Internal.Api.Credentials exposing (Credentials)
+import Internal.Api.Credentials as Cred exposing (Credentials)
 import Internal.Api.GetEvent.Main exposing (EventInput)
 import Internal.Api.Invite.Main exposing (InviteInput)
 import Internal.Api.JoinedMembers.Main exposing (JoinedMembersInput)
@@ -19,10 +19,17 @@ type alias FutureTask =
     C.FutureTask
 
 
+type alias EventInput =
+    { eventId : String
+    , roomId : String
+    }
+
+
 getEvent : EventInput -> Credentials -> FutureTask
-getEvent data cred =
+getEvent { eventId, roomId } cred =
     C.makeVBA cred
-        |> Chain.andThen (C.getEvent data)
+        |> Chain.andThen (C.withSentEvent eventId)
+        |> Chain.andThen (C.getEvent { roomId = roomId })
         |> C.toTask
 
 
@@ -63,8 +70,9 @@ redact { eventId, extraTransactionNoise, reason, roomId } cred =
                     |> Hash.toString
             )
         |> Chain.andThen (C.redact { eventId = eventId, reason = reason, roomId = roomId })
+        |> Chain.andThen (C.withSentEvent eventId)
         |> Chain.andThen
-            (Chain.maybe <| C.getEvent { eventId = eventId, roomId = roomId })
+            (Chain.maybe <| C.getEvent { roomId = roomId })
         |> C.toTask
 
 
@@ -91,7 +99,8 @@ sendMessageEvent { content, eventType, extraTransactionNoise, roomId } cred =
                     |> Hash.toString
             )
         |> Chain.andThen (C.sendMessageEvent { content = content, eventType = eventType, roomId = roomId })
-        -- TODO: Get event from API to see what it looks like
+        |> Chain.andThen
+            (Chain.maybe <| C.getEvent { roomId = roomId })
         |> C.toTask
 
 
@@ -99,7 +108,8 @@ sendStateEvent : SendStateKeyInput -> Credentials -> FutureTask
 sendStateEvent data cred =
     C.makeVBA cred
         |> Chain.andThen (C.sendStateEvent data)
-        -- TODO: Get event from API to see what it looks like
+        |> Chain.andThen
+            (Chain.maybe <| C.getEvent { roomId = data.roomId })
         |> C.toTask
 
 
@@ -108,3 +118,12 @@ sync data cred =
     C.makeVBA cred
         |> Chain.andThen (C.sync data)
         |> C.toTask
+
+
+loginMaybeSync : SyncInput -> Credentials -> FutureTask
+loginMaybeSync data cred =
+    C.makeVB cred
+        |> Chain.andThen (C.accessToken (Cred.refreshedAccessToken cred))
+        |> Chain.andThen
+            (Chain.maybe <| C.sync data)
+        |> C.toTask
diff --git a/src/Internal/Api/VaultUpdate.elm b/src/Internal/Api/VaultUpdate.elm
index 8241b15..fdb6295 100644
--- a/src/Internal/Api/VaultUpdate.elm
+++ b/src/Internal/Api/VaultUpdate.elm
@@ -94,7 +94,7 @@ accessToken ctoken =
 
 {-| Get an event from the API.
 -}
-getEvent : GetEvent.EventInput -> IdemChain VaultUpdate (VBA a)
+getEvent : GetEvent.EventInput -> IdemChain VaultUpdate (VBA { a | sentEvent : () })
 getEvent input =
     toChain
         (\output ->
@@ -212,12 +212,12 @@ redact input =
 
 {-| Send a message event to a room.
 -}
-sendMessageEvent : SendMessageEvent.SendMessageEventInput -> TaskChain VaultUpdate (VBAT a) (VBA a)
+sendMessageEvent : SendMessageEvent.SendMessageEventInput -> TaskChain VaultUpdate (VBAT a) (VBA { a | sentEvent : () })
 sendMessageEvent input =
     toChain
         (\output ->
             Chain.TaskChainPiece
-                { contextChange = Context.removeTransactionId
+                { contextChange = Context.removeTransactionId >> Context.setSentEvent output.eventId
                 , messages = [ MessageEventSent input output ]
                 }
         )
@@ -227,12 +227,12 @@ sendMessageEvent input =
 
 {-| Send a state key event to a room.
 -}
-sendStateEvent : SendStateKey.SendStateKeyInput -> IdemChain VaultUpdate (VBA a)
+sendStateEvent : SendStateKey.SendStateKeyInput -> TaskChain VaultUpdate (VBA a) (VBA { a | sentEvent : () })
 sendStateEvent input =
     toChain
         (\output ->
             Chain.TaskChainPiece
-                { contextChange = identity
+                { contextChange = Context.setSentEvent output.eventId
                 , messages = [ StateEventSent input output ]
                 }
         )
@@ -279,6 +279,18 @@ withBaseUrl baseUrl =
         |> always
 
 
+{-| Create a task that inserts an event id into the context, as if it were just sent.
+-}
+withSentEvent : String -> TaskChain VaultUpdate a { a | sentEvent : () }
+withSentEvent sentEvent =
+    { contextChange = Context.setSentEvent sentEvent
+    , messages = []
+    }
+        |> Chain.TaskChainPiece
+        |> Task.succeed
+        |> always
+
+
 {-| Create a task that inserts a transaction id into the context.
 -}
 withTransactionId : (Int -> String) -> TaskChain VaultUpdate a { a | transactionId : () }
diff --git a/src/Internal/Room.elm b/src/Internal/Room.elm
index 2bb98da..feb737d 100644
--- a/src/Internal/Room.elm
+++ b/src/Internal/Room.elm
@@ -4,7 +4,7 @@ module Internal.Room exposing (..)
 -}
 
 import Dict
-import Internal.Api.Credentials as Credentials exposing (Credentials)
+import Internal.Api.Credentials exposing (Credentials)
 import Internal.Api.Sync.V2.SpecObjects as Sync
 import Internal.Api.Task as Api
 import Internal.Api.VaultUpdate exposing (VaultUpdate)
diff --git a/src/Internal/Tools/Context.elm b/src/Internal/Tools/Context.elm
index 4938f8a..a7a959d 100644
--- a/src/Internal/Tools/Context.elm
+++ b/src/Internal/Tools/Context.elm
@@ -22,6 +22,7 @@ type Context a
     = Context
         { accessToken : String
         , baseUrl : String
+        , sentEvent : String
         , transactionId : String
         , usernameAndPassword : Maybe UsernameAndPassword
         , versions : List String
@@ -51,6 +52,7 @@ init =
     Context
         { accessToken = L.accessToken
         , baseUrl = L.baseUrl
+        , sentEvent = L.eventId
         , transactionId = L.transactionId
         , usernameAndPassword = Nothing
         , versions = L.versions
@@ -71,6 +73,13 @@ getBaseUrl (Context { baseUrl }) =
     baseUrl
 
 
+{-| Get the event that has been sent to the API recently.
+-}
+getSentEvent : Context { a | sentEvent : () } -> String
+getSentEvent (Context { sentEvent }) =
+    sentEvent
+
+
 {-| Get the transaction id from the Context.
 -}
 getTransactionId : Context { a | transactionId : () } -> String
@@ -106,6 +115,13 @@ setBaseUrl baseUrl (Context data) =
     Context { data | baseUrl = baseUrl }
 
 
+{-| Insert a sent event id into the context.
+-}
+setSentEvent : String -> Context a -> Context { a | sentEvent : () }
+setSentEvent sentEvent (Context data) =
+    Context { data | sentEvent = sentEvent }
+
+
 {-| Insert a transaction id into the context.
 -}
 setTransactionId : String -> Context a -> Context { a | transactionId : () }
@@ -134,6 +150,13 @@ removeBaseUrl (Context data) =
     Context data
 
 
+{-| Remove the sent event's id from the Context
+-}
+removeSentEvent : Context { a | sentEvent : () } -> Context a
+removeSentEvent (Context data) =
+    Context data
+
+
 {-| Remove the transaction id from the Context
 -}
 removeTransactionId : Context { a | transactionId : () } -> Context a
diff --git a/src/Internal/Tools/LoginValues.elm b/src/Internal/Tools/LoginValues.elm
index 8a3e5a9..e877b34 100644
--- a/src/Internal/Tools/LoginValues.elm
+++ b/src/Internal/Tools/LoginValues.elm
@@ -79,3 +79,20 @@ addUsernameAndPassword { username, password } t =
                 , password = password
                 , token = token
                 }
+
+
+removeToken : AccessToken -> AccessToken
+removeToken t =
+    case t of
+        NoAccess ->
+            NoAccess
+
+        AccessToken _ ->
+            NoAccess
+
+        UsernameAndPassword { username, password } ->
+            UsernameAndPassword
+                { username = username
+                , password = password
+                , token = Nothing
+                }
diff --git a/src/Internal/Vault.elm b/src/Internal/Vault.elm
index b0bd2f6..f57d0aa 100644
--- a/src/Internal/Vault.elm
+++ b/src/Internal/Vault.elm
@@ -9,12 +9,12 @@ This file combines the internal functions with the API endpoints to create a ful
 
 import Dict
 import Internal.Api.Credentials as Credentials exposing (Credentials)
+import Internal.Api.Sync.Main exposing (SyncInput)
 import Internal.Api.Task as Api
 import Internal.Api.VaultUpdate exposing (VaultUpdate(..))
 import Internal.Event as Event
 import Internal.Room as Room
 import Internal.Tools.Exceptions as X
-import Internal.Values.Event as IEvent
 import Internal.Values.Room as IRoom
 import Internal.Values.StateManager as StateManager
 import Internal.Values.Vault as Internal
@@ -195,14 +195,44 @@ updateWith vaultUpdate ((Vault ({ cred, context } as data)) as credentials) =
 -}
 sync : Vault -> Task X.Error VaultUpdate
 sync (Vault { cred, context }) =
-    Api.sync
-        { filter = Nothing
-        , fullState = Nothing
-        , setPresence = Nothing
-        , since = Internal.getSince cred
-        , timeout = Just 30
-        }
-        context
+    let
+        syncInput : SyncInput
+        syncInput =
+            { filter = Nothing
+            , fullState = Nothing
+            , setPresence = Nothing
+            , since = Internal.getSince cred
+            , timeout = Just 30
+            }
+    in
+    Api.sync syncInput context
+        -- TODO: The sync function is described as "updating all the tokens".
+        -- TODO: For this reason, (only) the sync function should handle errors
+        -- TODO: that indicate that the user's access tokens have expired.
+        -- TODO: This implementation needs to be tested.
+        |> Task.onError
+            (\err ->
+                case err of
+                    X.UnsupportedSpecVersion ->
+                        Task.fail err
+
+                    X.SDKException _ ->
+                        Task.fail err
+
+                    X.InternetException _ ->
+                        Task.fail err
+
+                    -- TODO: The login should be different when soft_logout.
+                    -- TODO: Add support for refresh token.
+                    X.ServerException (X.M_UNKNOWN_TOKEN { soft_logout }) ->
+                        Api.loginMaybeSync syncInput context
+
+                    X.ServerException (X.M_MISSING_TOKEN { soft_logout }) ->
+                        Api.loginMaybeSync syncInput context
+
+                    X.ServerException _ ->
+                        Task.fail err
+            )
 
 
 {-| Get a list of all synchronised rooms.