diff --git a/apps/emqx_ft/src/emqx_ft.erl b/apps/emqx_ft/src/emqx_ft.erl
index e3f6cbe1c..064b6e066 100644
--- a/apps/emqx_ft/src/emqx_ft.erl
+++ b/apps/emqx_ft/src/emqx_ft.erl
@@ -45,7 +45,8 @@
     bytes/0,
     offset/0,
     filemeta/0,
-    segment/0
+    segment/0,
+    checksum/0
 ]).
 
 %% Number of bytes
@@ -57,6 +58,7 @@
 -type fileid() :: binary().
 -type transfer() :: {clientid(), fileid()}.
 -type offset() :: bytes().
+-type checksum() :: {_Algo :: atom(), _Digest :: binary()}.
 
 -type filemeta() :: #{
     %% Display name
@@ -68,7 +70,7 @@
     %% currently do not condider that an error (or, specifically, a signal that
     %% the resulting file is corrupted during transmission).
     size => _Bytes :: non_neg_integer(),
-    checksum => {sha256, <<_:256>>},
+    checksum => checksum(),
     expire_at := emqx_datetime:epoch_second(),
     %% TTL of individual segments
     %% Somewhat confusing that we won't know it on the nodes where the filemeta
diff --git a/apps/emqx_ft/src/emqx_ft_storage_exporter.erl b/apps/emqx_ft/src/emqx_ft_storage_exporter.erl
index 297762d28..444d686a8 100644
--- a/apps/emqx_ft/src/emqx_ft_storage_exporter.erl
+++ b/apps/emqx_ft/src/emqx_ft_storage_exporter.erl
@@ -39,10 +39,21 @@
 -type storage() :: emxt_ft_storage_fs:storage().
 -type transfer() :: emqx_ft:transfer().
 -type filemeta() :: emqx_ft:filemeta().
+-type checksum() :: emqx_ft:checksum().
 
 -type exporter_conf() :: map().
 -type export_st() :: term().
--opaque export() :: {module(), export_st()}.
+-type hash_state() :: term().
+-opaque export() :: #{
+    mod := module(),
+    st := export_st(),
+    hash := hash_state(),
+    filemeta := filemeta()
+}.
+
+%%------------------------------------------------------------------------------
+%% Behaviour
+%%------------------------------------------------------------------------------
 
 -callback start_export(exporter_conf(), transfer(), filemeta()) ->
     {ok, export_st()} | {error, _Reason}.
@@ -51,7 +62,7 @@
 -callback write(ExportSt :: export_st(), iodata()) ->
     {ok, ExportSt :: export_st()} | {error, _Reason}.
 
--callback complete(ExportSt :: export_st()) ->
+-callback complete(_ExportSt :: export_st(), _Checksum :: checksum()) ->
     ok | {error, _Reason}.
 
 -callback discard(ExportSt :: export_st()) ->
@@ -60,7 +71,9 @@
 -callback list(storage()) ->
     {ok, [emqx_ft_storage:file_info()]} | {error, _Reason}.
 
-%%
+%%------------------------------------------------------------------------------
+%% API
+%%------------------------------------------------------------------------------
 
 -spec start_export(storage(), transfer(), filemeta()) ->
     {ok, export()} | {error, _Reason}.
@@ -68,29 +81,43 @@ start_export(Storage, Transfer, Filemeta) ->
     {ExporterMod, ExporterConf} = exporter(Storage),
     case ExporterMod:start_export(ExporterConf, Transfer, Filemeta) of
         {ok, ExportSt} ->
-            {ok, {ExporterMod, ExportSt}};
+            {ok, #{
+                mod => ExporterMod,
+                st => ExportSt,
+                hash => init_checksum(Filemeta),
+                filemeta => Filemeta
+            }};
         {error, _} = Error ->
             Error
     end.
 
 -spec write(export(), iodata()) ->
     {ok, export()} | {error, _Reason}.
-write({ExporterMod, ExportSt}, Content) ->
+write(#{mod := ExporterMod, st := ExportSt, hash := Hash} = Export, Content) ->
     case ExporterMod:write(ExportSt, Content) of
         {ok, ExportStNext} ->
-            {ok, {ExporterMod, ExportStNext}};
+            {ok, Export#{
+                st := ExportStNext,
+                hash := update_checksum(Hash, Content)
+            }};
         {error, _} = Error ->
             Error
     end.
 
 -spec complete(export()) ->
     ok | {error, _Reason}.
-complete({ExporterMod, ExportSt}) ->
-    ExporterMod:complete(ExportSt).
+complete(#{mod := ExporterMod, st := ExportSt, hash := Hash, filemeta := Filemeta}) ->
+    case verify_checksum(Hash, Filemeta) of
+        {ok, Checksum} ->
+            ExporterMod:complete(ExportSt, Checksum);
+        {error, _} = Error ->
+            _ = ExporterMod:discard(ExportSt),
+            Error
+    end.
 
 -spec discard(export()) ->
     ok | {error, _Reason}.
-discard({ExporterMod, ExportSt}) ->
+discard(#{mod := ExporterMod, st := ExportSt}) ->
     ExporterMod:discard(ExportSt).
 
 -spec list(storage()) ->
@@ -99,7 +126,10 @@ list(Storage) ->
     {ExporterMod, ExporterOpts} = exporter(Storage),
     ExporterMod:list(ExporterOpts).
 
--spec exporter(storage()) -> {module(), _ExporterOptions}.
+%%------------------------------------------------------------------------------
+%% Internal functions
+%%------------------------------------------------------------------------------
+
 exporter(Storage) ->
     case maps:get(exporter, Storage) of
         #{type := local} = Options ->
@@ -111,3 +141,22 @@ exporter(Storage) ->
 -spec without_type(exporter_conf()) -> exporter_conf().
 without_type(#{type := _} = Options) ->
     maps:without([type], Options).
+
+init_checksum(#{checksum := {Algo, _}}) ->
+    crypto:hash_init(Algo);
+init_checksum(#{}) ->
+    crypto:hash_init(sha256).
+
+update_checksum(Ctx, IoData) ->
+    crypto:hash_update(Ctx, IoData).
+
+verify_checksum(Ctx, #{checksum := {Algo, Digest} = Checksum}) ->
+    case crypto:hash_final(Ctx) of
+        Digest ->
+            {ok, Checksum};
+        Mismatch ->
+            {error, {checksum, Algo, binary:encode_hex(Mismatch)}}
+    end;
+verify_checksum(Ctx, #{}) ->
+    Digest = crypto:hash_final(Ctx),
+    {ok, {sha256, Digest}}.
diff --git a/apps/emqx_ft/src/emqx_ft_storage_exporter_fs.erl b/apps/emqx_ft/src/emqx_ft_storage_exporter_fs.erl
index 64c0e325a..fd1956009 100644
--- a/apps/emqx_ft/src/emqx_ft_storage_exporter_fs.erl
+++ b/apps/emqx_ft/src/emqx_ft_storage_exporter_fs.erl
@@ -24,7 +24,7 @@
 
 -export([start_export/3]).
 -export([write/2]).
--export([complete/1]).
+-export([complete/2]).
 -export([discard/1]).
 -export([list/1]).
 
@@ -50,12 +50,11 @@
 
 -type file_error() :: emqx_ft_storage_fs:file_error().
 
--type export() :: #{
+-type export_st() :: #{
     path := file:name(),
     handle := io:device(),
     result := file:name(),
-    meta := filemeta(),
-    hash := crypto:hash_state()
+    meta := filemeta()
 }.
 
 -type reader() :: pid().
@@ -92,7 +91,7 @@
 %%
 
 -spec start_export(options(), transfer(), filemeta()) ->
-    {ok, export()} | {error, file_error()}.
+    {ok, export_st()} | {error, file_error()}.
 start_export(Options, Transfer, Filemeta = #{name := Filename}) ->
     TempFilepath = mk_temp_absfilepath(Options, Transfer, Filename),
     ResultFilepath = mk_absfilepath(Options, Transfer, result, Filename),
@@ -103,47 +102,41 @@ start_export(Options, Transfer, Filemeta = #{name := Filename}) ->
                 path => TempFilepath,
                 handle => Handle,
                 result => ResultFilepath,
-                meta => Filemeta,
-                hash => init_checksum(Filemeta)
+                meta => Filemeta
             }};
         {error, _} = Error ->
             Error
     end.
 
--spec write(export(), iodata()) ->
-    {ok, export()} | {error, file_error()}.
-write(Export = #{handle := Handle, hash := Ctx}, IoData) ->
+-spec write(export_st(), iodata()) ->
+    {ok, export_st()} | {error, file_error()}.
+write(ExportSt = #{handle := Handle}, IoData) ->
     case file:write(Handle, IoData) of
         ok ->
-            {ok, Export#{hash := update_checksum(Ctx, IoData)}};
+            {ok, ExportSt};
         {error, _} = Error ->
-            _ = discard(Export),
+            _ = discard(ExportSt),
             Error
     end.
 
--spec complete(export()) ->
+-spec complete(export_st(), emqx_ft:checksum()) ->
     ok | {error, {checksum, _Algo, _Computed}} | {error, file_error()}.
 complete(
-    Export = #{
+    #{
         path := Filepath,
         handle := Handle,
         result := ResultFilepath,
-        meta := FilemetaIn,
-        hash := Ctx
-    }
+        meta := FilemetaIn
+    },
+    Checksum
 ) ->
-    case verify_checksum(Ctx, FilemetaIn) of
-        {ok, Filemeta} ->
-            ok = file:close(Handle),
-            _ = filelib:ensure_dir(ResultFilepath),
-            _ = file:write_file(mk_manifest_filename(ResultFilepath), encode_filemeta(Filemeta)),
-            file:rename(Filepath, ResultFilepath);
-        {error, _} = Error ->
-            _ = discard(Export),
-            Error
-    end.
+    Filemeta = FilemetaIn#{checksum => Checksum},
+    ok = file:close(Handle),
+    _ = filelib:ensure_dir(ResultFilepath),
+    _ = file:write_file(mk_manifest_filename(ResultFilepath), encode_filemeta(Filemeta)),
+    file:rename(Filepath, ResultFilepath).
 
--spec discard(export()) ->
+-spec discard(export_st()) ->
     ok.
 discard(#{path := Filepath, handle := Handle}) ->
     ok = file:close(Handle),
@@ -297,27 +290,6 @@ list(_Options) ->
 
 %%
 
-init_checksum(#{checksum := {Algo, _}}) ->
-    crypto:hash_init(Algo);
-init_checksum(#{}) ->
-    crypto:hash_init(sha256).
-
-update_checksum(Ctx, IoData) ->
-    crypto:hash_update(Ctx, IoData).
-
-verify_checksum(Ctx, Filemeta = #{checksum := {Algo, Digest}}) ->
-    case crypto:hash_final(Ctx) of
-        Digest ->
-            {ok, Filemeta};
-        Mismatch ->
-            {error, {checksum, Algo, binary:encode_hex(Mismatch)}}
-    end;
-verify_checksum(Ctx, Filemeta = #{}) ->
-    Digest = crypto:hash_final(Ctx),
-    {ok, Filemeta#{checksum => {sha256, Digest}}}.
-
-%%
-
 -define(PRELUDE(Vsn, Meta), [<<"filemeta">>, Vsn, Meta]).
 
 encode_filemeta(Meta) ->