diff --git a/modules/openapi-generator/src/main/resources/erlang-server/api.mustache b/modules/openapi-generator/src/main/resources/erlang-server/api.mustache
index f876b3a5361f..ba8f13854f61 100644
--- a/modules/openapi-generator/src/main/resources/erlang-server/api.mustache
+++ b/modules/openapi-generator/src/main/resources/erlang-server/api.mustache
@@ -108,7 +108,8 @@ for the `OperationID` operation.
         OperationID :: operation_id(),
         Code :: 200..599,
         Body :: jesse:json_term(),
-        ValidatorState :: jesse_state:state()) -> ok | no_return().
+        ValidatorState :: jesse_state:state()) ->
+    ok | {ok, term()} | [ok | {ok, term()}] | no_return().
 {{#apiInfo}}{{#apis}}{{#operations}}{{#operation}}{{#responses}}validate_response('{{operationId}}', {{code}}, Body, ValidatorState) ->
     validate_response_body('{{dataType}}', '{{baseType}}', Body, ValidatorState);
 {{/responses}}
@@ -393,7 +394,7 @@ to_list(V) when is_atom(V)    -> atom_to_list(V);
 to_list(V) when is_integer(V) -> integer_to_list(V);
 to_list(V) when is_float(V)   -> float_to_list(V).
 
--spec to_float(iodata()) -> number().
+-spec to_float(iodata()) -> float().
 to_float(V) ->
     binary_to_float(iolist_to_binary([V])).
 
@@ -438,7 +439,7 @@ get_openapi_path() ->
 
 -include_lib("kernel/include/file.hrl").
 
--spec priv_dir(Application :: atom()) -> file:filename().
+-spec priv_dir(Application :: atom()) -> file:name_all().
 priv_dir(AppName) ->
     case code:priv_dir(AppName) of
         Value when is_list(Value) ->
diff --git a/modules/openapi-generator/src/main/resources/erlang-server/rebar.config.mustache b/modules/openapi-generator/src/main/resources/erlang-server/rebar.config.mustache
index c2ecd8c9b78f..50cd482ca39b 100644
--- a/modules/openapi-generator/src/main/resources/erlang-server/rebar.config.mustache
+++ b/modules/openapi-generator/src/main/resources/erlang-server/rebar.config.mustache
@@ -6,7 +6,10 @@
     {jesse, "1.8.1"}
 ]}.
 
-{dialyzer, [{plt_extra_apps, [cowboy, cowlib, ranch, jesse]}]}.
+{dialyzer,
+ [{plt_extra_apps, [cowboy, cowlib, ranch, jesse]},
+  {warnings, [missing_return, unknown]}
+]}.
 
 {xref_checks,
  [undefined_function_calls, deprecated_function_calls, deprecated_functions]}.
diff --git a/samples/server/echo_api/erlang-server/rebar.config b/samples/server/echo_api/erlang-server/rebar.config
index c2ecd8c9b78f..50cd482ca39b 100644
--- a/samples/server/echo_api/erlang-server/rebar.config
+++ b/samples/server/echo_api/erlang-server/rebar.config
@@ -6,7 +6,10 @@
     {jesse, "1.8.1"}
 ]}.
 
-{dialyzer, [{plt_extra_apps, [cowboy, cowlib, ranch, jesse]}]}.
+{dialyzer,
+ [{plt_extra_apps, [cowboy, cowlib, ranch, jesse]},
+  {warnings, [missing_return, unknown]}
+]}.
 
 {xref_checks,
  [undefined_function_calls, deprecated_function_calls, deprecated_functions]}.
diff --git a/samples/server/echo_api/erlang-server/src/openapi_api.erl b/samples/server/echo_api/erlang-server/src/openapi_api.erl
index fd60a684c82a..b796f2df4a36 100644
--- a/samples/server/echo_api/erlang-server/src/openapi_api.erl
+++ b/samples/server/echo_api/erlang-server/src/openapi_api.erl
@@ -108,7 +108,8 @@ for the `OperationID` operation.
         OperationID :: operation_id(),
         Code :: 200..599,
         Body :: jesse:json_term(),
-        ValidatorState :: jesse_state:state()) -> ok | no_return().
+        ValidatorState :: jesse_state:state()) ->
+    ok | {ok, term()} | [ok | {ok, term()}] | no_return().
 validate_response('TestAuthHttpBasic', 200, Body, ValidatorState) ->
     validate_response_body('binary', 'string', Body, ValidatorState);
 validate_response('TestAuthHttpBearer', 200, Body, ValidatorState) ->
@@ -872,7 +873,7 @@ to_list(V) when is_atom(V)    -> atom_to_list(V);
 to_list(V) when is_integer(V) -> integer_to_list(V);
 to_list(V) when is_float(V)   -> float_to_list(V).
 
--spec to_float(iodata()) -> number().
+-spec to_float(iodata()) -> float().
 to_float(V) ->
     binary_to_float(iolist_to_binary([V])).
 
@@ -917,7 +918,7 @@ get_openapi_path() ->
 
 -include_lib("kernel/include/file.hrl").
 
--spec priv_dir(Application :: atom()) -> file:filename().
+-spec priv_dir(Application :: atom()) -> file:name_all().
 priv_dir(AppName) ->
     case code:priv_dir(AppName) of
         Value when is_list(Value) ->
diff --git a/samples/server/petstore/erlang-server/rebar.config b/samples/server/petstore/erlang-server/rebar.config
index c2ecd8c9b78f..50cd482ca39b 100644
--- a/samples/server/petstore/erlang-server/rebar.config
+++ b/samples/server/petstore/erlang-server/rebar.config
@@ -6,7 +6,10 @@
     {jesse, "1.8.1"}
 ]}.
 
-{dialyzer, [{plt_extra_apps, [cowboy, cowlib, ranch, jesse]}]}.
+{dialyzer,
+ [{plt_extra_apps, [cowboy, cowlib, ranch, jesse]},
+  {warnings, [missing_return, unknown]}
+]}.
 
 {xref_checks,
  [undefined_function_calls, deprecated_function_calls, deprecated_functions]}.
diff --git a/samples/server/petstore/erlang-server/src/openapi_api.erl b/samples/server/petstore/erlang-server/src/openapi_api.erl
index f74f29beeff6..16ad18e97823 100644
--- a/samples/server/petstore/erlang-server/src/openapi_api.erl
+++ b/samples/server/petstore/erlang-server/src/openapi_api.erl
@@ -108,7 +108,8 @@ for the `OperationID` operation.
         OperationID :: operation_id(),
         Code :: 200..599,
         Body :: jesse:json_term(),
-        ValidatorState :: jesse_state:state()) -> ok | no_return().
+        ValidatorState :: jesse_state:state()) ->
+    ok | {ok, term()} | [ok | {ok, term()}] | no_return().
 validate_response('AddPet', 200, Body, ValidatorState) ->
     validate_response_body('Pet', 'Pet', Body, ValidatorState);
 validate_response('AddPet', 405, Body, ValidatorState) ->
@@ -719,7 +720,7 @@ to_list(V) when is_atom(V)    -> atom_to_list(V);
 to_list(V) when is_integer(V) -> integer_to_list(V);
 to_list(V) when is_float(V)   -> float_to_list(V).
 
--spec to_float(iodata()) -> number().
+-spec to_float(iodata()) -> float().
 to_float(V) ->
     binary_to_float(iolist_to_binary([V])).
 
@@ -764,7 +765,7 @@ get_openapi_path() ->
 
 -include_lib("kernel/include/file.hrl").
 
--spec priv_dir(Application :: atom()) -> file:filename().
+-spec priv_dir(Application :: atom()) -> file:name_all().
 priv_dir(AppName) ->
     case code:priv_dir(AppName) of
         Value when is_list(Value) ->