diff --git a/rebar.config b/rebar.config
index 754ce85..ad30ca8 100644
--- a/rebar.config
+++ b/rebar.config
@@ -3,8 +3,7 @@
 
 {deps, [
         {jiffy, "0.14.11"},
-        {erlexec, "1.7.1"},
-        {b64fast, "0.2.1"}
+        {erlexec, "1.7.1"}
        ]}.
 
 
@@ -30,20 +29,6 @@
     ]}
 ]}.
 
-{overrides,
- [{override, b64fast,
-   [
-    {plugins, [pc]},
-    {artifacts, ["priv/b64fast.so"]},
-    {so_name, "b64fast.so"},
-    {provider_hooks, [
-                      {post,
-                       [{compile, {pc, compile}},
-                        {clean, {pc, clean}}]}
-                     ]}
-   ]}
- ]}.
-
 {dialyzer, [
     {warnings, [unknown, no_return, error_handling]},
     {plt_apps, top_level_deps},
diff --git a/rebar.lock b/rebar.lock
index 49a106a..a0db0b9 100644
--- a/rebar.lock
+++ b/rebar.lock
@@ -1,10 +1,8 @@
 {"1.1.0",
-[{<<"b64fast">>,{pkg,<<"b64fast">>,<<"0.2.1">>},0},
- {<<"erlexec">>,{pkg,<<"erlexec">>,<<"1.7.1">>},0},
+[{<<"erlexec">>,{pkg,<<"erlexec">>,<<"1.7.1">>},0},
  {<<"jiffy">>,{pkg,<<"jiffy">>,<<"0.14.11">>},0}]}.
 [
 {pkg_hash,[
- {<<"b64fast">>, <<"EF67EFD73109BF52A83338A2DED30D0DC4EC1B11449B4C43DB970D3FC96CC9CD">>},
  {<<"erlexec">>, <<"6DDBD40FA202084ED0BDAF95A50C334ACAA5644AE213B903CD4094A78AE79734">>},
  {<<"jiffy">>, <<"919A87D491C5A6B5E3BBC27FAFEDC3A0761CA0B4C405394F121F582FD4E3F0E5">>}]}
 ].
diff --git a/src/erlmld.app.src b/src/erlmld.app.src
index f10253a..d78c437 100644
--- a/src/erlmld.app.src
+++ b/src/erlmld.app.src
@@ -20,8 +20,7 @@
     stdlib,
     crypto,
     erlexec,
-    jiffy,
-    b64fast]},
+    jiffy]},
   {modules, []},
   {env, [
          %% if nonzero, use a specific listen port instead of a random one:
@@ -89,6 +88,9 @@
          %% if true, don't fail if kcl encounters child shards with open parents, which
          %% can occur when processing dynamo streams on very large tables (requires
          %% patched KCL):
-         {ignore_unexpected_child_shards, false}
+         {ignore_unexpected_child_shards, false},
+
+         %% base64 decoder {mod, fun}
+         {base64_decoder, {base64, decode}}
         ]}
  ]}.
diff --git a/src/erlmld_wrk_statem.erl b/src/erlmld_wrk_statem.erl
index b28a6b7..d09af79 100644
--- a/src/erlmld_wrk_statem.erl
+++ b/src/erlmld_wrk_statem.erl
@@ -664,9 +664,9 @@ stream_record(Record, PartitionKey, Data, SequenceNumber) ->
 
 
 deaggregate_kpl_records(R, Records) ->
+    Base64Decoder = application:get_env(erlmld, base64_decoder, {base64, decode}),
     lists:flatmap(fun (#{<<"data">> := RecordData} = Record) ->
-                          %% note: b64fast will fail if the data contains whitespace.
-                          deaggregate_kpl_record(R, Record, b64fast:decode64(RecordData))
+                          deaggregate_kpl_record(R, Record, b64decode(Base64Decoder, RecordData))
                   end, Records).
 
 
@@ -730,6 +730,10 @@ encode_seqno_base(X) when is_atom(X), X /= undefined ->
     atom_to_binary(X, utf8).
 
 
+b64decode({M, F}, Data) ->
+    M:F(Data).
+
+
 %%%===================================================================
 %%% TESTS
 %%%===================================================================