diff --git a/Makefile b/Makefile
index db73104..fb54db3 100644
--- a/Makefile
+++ b/Makefile
@@ -5,6 +5,7 @@ install:
 .PHONY: generate/examples
 generate/examples:
 	go generate ./examples/pingpong
+	go generate ./examples/oneof
 
 .PHONY: run/example/server
 run/example/server: install generate/examples
diff --git a/examples/oneof/oneof.go b/examples/oneof/oneof.go
new file mode 100644
index 0000000..6817d13
--- /dev/null
+++ b/examples/oneof/oneof.go
@@ -0,0 +1,4 @@
+package oneof
+
+// To regenerate the protocol buffer output for this package, run `go generate`
+//go:generate protoc --go_out=. --go_opt=paths=source_relative --rangerrpc_out=. oneof.proto
diff --git a/examples/oneof/oneof.pb.go b/examples/oneof/oneof.pb.go
new file mode 100644
index 0000000..51078f6
--- /dev/null
+++ b/examples/oneof/oneof.pb.go
@@ -0,0 +1,289 @@
+// Code generated by protoc-gen-go. DO NOT EDIT.
+// versions:
+// 	protoc-gen-go v1.26.0
+// 	protoc        v3.19.1
+// source: oneof.proto
+
+package oneof
+
+import (
+	protoreflect "google.golang.org/protobuf/reflect/protoreflect"
+	protoimpl "google.golang.org/protobuf/runtime/protoimpl"
+	reflect "reflect"
+	sync "sync"
+)
+
+const (
+	// Verify that this generated code is sufficiently up-to-date.
+	_ = protoimpl.EnforceVersion(20 - protoimpl.MinVersion)
+	// Verify that runtime/protoimpl is sufficiently up-to-date.
+	_ = protoimpl.EnforceVersion(protoimpl.MaxVersion - 20)
+)
+
+type OneOfRequest struct {
+	state         protoimpl.MessageState
+	sizeCache     protoimpl.SizeCache
+	unknownFields protoimpl.UnknownFields
+
+	// Types that are assignable to Options:
+	//	*OneOfRequest_Text
+	//	*OneOfRequest_Number
+	Options isOneOfRequest_Options `protobuf_oneof:"options"`
+}
+
+func (x *OneOfRequest) Reset() {
+	*x = OneOfRequest{}
+	if protoimpl.UnsafeEnabled {
+		mi := &file_oneof_proto_msgTypes[0]
+		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
+		ms.StoreMessageInfo(mi)
+	}
+}
+
+func (x *OneOfRequest) String() string {
+	return protoimpl.X.MessageStringOf(x)
+}
+
+func (*OneOfRequest) ProtoMessage() {}
+
+func (x *OneOfRequest) ProtoReflect() protoreflect.Message {
+	mi := &file_oneof_proto_msgTypes[0]
+	if protoimpl.UnsafeEnabled && x != nil {
+		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
+		if ms.LoadMessageInfo() == nil {
+			ms.StoreMessageInfo(mi)
+		}
+		return ms
+	}
+	return mi.MessageOf(x)
+}
+
+// Deprecated: Use OneOfRequest.ProtoReflect.Descriptor instead.
+func (*OneOfRequest) Descriptor() ([]byte, []int) {
+	return file_oneof_proto_rawDescGZIP(), []int{0}
+}
+
+func (m *OneOfRequest) GetOptions() isOneOfRequest_Options {
+	if m != nil {
+		return m.Options
+	}
+	return nil
+}
+
+func (x *OneOfRequest) GetText() string {
+	if x, ok := x.GetOptions().(*OneOfRequest_Text); ok {
+		return x.Text
+	}
+	return ""
+}
+
+func (x *OneOfRequest) GetNumber() int64 {
+	if x, ok := x.GetOptions().(*OneOfRequest_Number); ok {
+		return x.Number
+	}
+	return 0
+}
+
+type isOneOfRequest_Options interface {
+	isOneOfRequest_Options()
+}
+
+type OneOfRequest_Text struct {
+	Text string `protobuf:"bytes,1,opt,name=text,proto3,oneof"`
+}
+
+type OneOfRequest_Number struct {
+	Number int64 `protobuf:"varint,2,opt,name=number,proto3,oneof"`
+}
+
+func (*OneOfRequest_Text) isOneOfRequest_Options() {}
+
+func (*OneOfRequest_Number) isOneOfRequest_Options() {}
+
+type OneOfReply struct {
+	state         protoimpl.MessageState
+	sizeCache     protoimpl.SizeCache
+	unknownFields protoimpl.UnknownFields
+
+	// Types that are assignable to Options:
+	//	*OneOfReply_Text
+	//	*OneOfReply_Number
+	Options isOneOfReply_Options `protobuf_oneof:"options"`
+}
+
+func (x *OneOfReply) Reset() {
+	*x = OneOfReply{}
+	if protoimpl.UnsafeEnabled {
+		mi := &file_oneof_proto_msgTypes[1]
+		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
+		ms.StoreMessageInfo(mi)
+	}
+}
+
+func (x *OneOfReply) String() string {
+	return protoimpl.X.MessageStringOf(x)
+}
+
+func (*OneOfReply) ProtoMessage() {}
+
+func (x *OneOfReply) ProtoReflect() protoreflect.Message {
+	mi := &file_oneof_proto_msgTypes[1]
+	if protoimpl.UnsafeEnabled && x != nil {
+		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
+		if ms.LoadMessageInfo() == nil {
+			ms.StoreMessageInfo(mi)
+		}
+		return ms
+	}
+	return mi.MessageOf(x)
+}
+
+// Deprecated: Use OneOfReply.ProtoReflect.Descriptor instead.
+func (*OneOfReply) Descriptor() ([]byte, []int) {
+	return file_oneof_proto_rawDescGZIP(), []int{1}
+}
+
+func (m *OneOfReply) GetOptions() isOneOfReply_Options {
+	if m != nil {
+		return m.Options
+	}
+	return nil
+}
+
+func (x *OneOfReply) GetText() string {
+	if x, ok := x.GetOptions().(*OneOfReply_Text); ok {
+		return x.Text
+	}
+	return ""
+}
+
+func (x *OneOfReply) GetNumber() int64 {
+	if x, ok := x.GetOptions().(*OneOfReply_Number); ok {
+		return x.Number
+	}
+	return 0
+}
+
+type isOneOfReply_Options interface {
+	isOneOfReply_Options()
+}
+
+type OneOfReply_Text struct {
+	Text string `protobuf:"bytes,1,opt,name=text,proto3,oneof"`
+}
+
+type OneOfReply_Number struct {
+	Number int64 `protobuf:"varint,2,opt,name=number,proto3,oneof"`
+}
+
+func (*OneOfReply_Text) isOneOfReply_Options() {}
+
+func (*OneOfReply_Number) isOneOfReply_Options() {}
+
+var File_oneof_proto protoreflect.FileDescriptor
+
+var file_oneof_proto_rawDesc = []byte{
+	0x0a, 0x0b, 0x6f, 0x6e, 0x65, 0x6f, 0x66, 0x2e, 0x70, 0x72, 0x6f, 0x74, 0x6f, 0x12, 0x05, 0x6f,
+	0x6e, 0x65, 0x6f, 0x66, 0x22, 0x49, 0x0a, 0x0c, 0x4f, 0x6e, 0x65, 0x4f, 0x66, 0x52, 0x65, 0x71,
+	0x75, 0x65, 0x73, 0x74, 0x12, 0x14, 0x0a, 0x04, 0x74, 0x65, 0x78, 0x74, 0x18, 0x01, 0x20, 0x01,
+	0x28, 0x09, 0x48, 0x00, 0x52, 0x04, 0x74, 0x65, 0x78, 0x74, 0x12, 0x18, 0x0a, 0x06, 0x6e, 0x75,
+	0x6d, 0x62, 0x65, 0x72, 0x18, 0x02, 0x20, 0x01, 0x28, 0x03, 0x48, 0x00, 0x52, 0x06, 0x6e, 0x75,
+	0x6d, 0x62, 0x65, 0x72, 0x42, 0x09, 0x0a, 0x07, 0x6f, 0x70, 0x74, 0x69, 0x6f, 0x6e, 0x73, 0x22,
+	0x47, 0x0a, 0x0a, 0x4f, 0x6e, 0x65, 0x4f, 0x66, 0x52, 0x65, 0x70, 0x6c, 0x79, 0x12, 0x14, 0x0a,
+	0x04, 0x74, 0x65, 0x78, 0x74, 0x18, 0x01, 0x20, 0x01, 0x28, 0x09, 0x48, 0x00, 0x52, 0x04, 0x74,
+	0x65, 0x78, 0x74, 0x12, 0x18, 0x0a, 0x06, 0x6e, 0x75, 0x6d, 0x62, 0x65, 0x72, 0x18, 0x02, 0x20,
+	0x01, 0x28, 0x03, 0x48, 0x00, 0x52, 0x06, 0x6e, 0x75, 0x6d, 0x62, 0x65, 0x72, 0x42, 0x09, 0x0a,
+	0x07, 0x6f, 0x70, 0x74, 0x69, 0x6f, 0x6e, 0x73, 0x32, 0x37, 0x0a, 0x05, 0x4f, 0x6e, 0x65, 0x4f,
+	0x66, 0x12, 0x2e, 0x0a, 0x04, 0x45, 0x63, 0x68, 0x6f, 0x12, 0x13, 0x2e, 0x6f, 0x6e, 0x65, 0x6f,
+	0x66, 0x2e, 0x4f, 0x6e, 0x65, 0x4f, 0x66, 0x52, 0x65, 0x71, 0x75, 0x65, 0x73, 0x74, 0x1a, 0x11,
+	0x2e, 0x6f, 0x6e, 0x65, 0x6f, 0x66, 0x2e, 0x4f, 0x6e, 0x65, 0x4f, 0x66, 0x52, 0x65, 0x70, 0x6c,
+	0x79, 0x42, 0x23, 0x5a, 0x21, 0x67, 0x6f, 0x2e, 0x6d, 0x6f, 0x6e, 0x64, 0x6f, 0x6f, 0x2e, 0x69,
+	0x6f, 0x2f, 0x66, 0x61, 0x6c, 0x63, 0x6f, 0x6e, 0x2f, 0x65, 0x78, 0x61, 0x6d, 0x70, 0x6c, 0x65,
+	0x2f, 0x6f, 0x6e, 0x65, 0x6f, 0x66, 0x62, 0x06, 0x70, 0x72, 0x6f, 0x74, 0x6f, 0x33,
+}
+
+var (
+	file_oneof_proto_rawDescOnce sync.Once
+	file_oneof_proto_rawDescData = file_oneof_proto_rawDesc
+)
+
+func file_oneof_proto_rawDescGZIP() []byte {
+	file_oneof_proto_rawDescOnce.Do(func() {
+		file_oneof_proto_rawDescData = protoimpl.X.CompressGZIP(file_oneof_proto_rawDescData)
+	})
+	return file_oneof_proto_rawDescData
+}
+
+var file_oneof_proto_msgTypes = make([]protoimpl.MessageInfo, 2)
+var file_oneof_proto_goTypes = []interface{}{
+	(*OneOfRequest)(nil), // 0: oneof.OneOfRequest
+	(*OneOfReply)(nil),   // 1: oneof.OneOfReply
+}
+var file_oneof_proto_depIdxs = []int32{
+	0, // 0: oneof.OneOf.Echo:input_type -> oneof.OneOfRequest
+	1, // 1: oneof.OneOf.Echo:output_type -> oneof.OneOfReply
+	1, // [1:2] is the sub-list for method output_type
+	0, // [0:1] is the sub-list for method input_type
+	0, // [0:0] is the sub-list for extension type_name
+	0, // [0:0] is the sub-list for extension extendee
+	0, // [0:0] is the sub-list for field type_name
+}
+
+func init() { file_oneof_proto_init() }
+func file_oneof_proto_init() {
+	if File_oneof_proto != nil {
+		return
+	}
+	if !protoimpl.UnsafeEnabled {
+		file_oneof_proto_msgTypes[0].Exporter = func(v interface{}, i int) interface{} {
+			switch v := v.(*OneOfRequest); i {
+			case 0:
+				return &v.state
+			case 1:
+				return &v.sizeCache
+			case 2:
+				return &v.unknownFields
+			default:
+				return nil
+			}
+		}
+		file_oneof_proto_msgTypes[1].Exporter = func(v interface{}, i int) interface{} {
+			switch v := v.(*OneOfReply); i {
+			case 0:
+				return &v.state
+			case 1:
+				return &v.sizeCache
+			case 2:
+				return &v.unknownFields
+			default:
+				return nil
+			}
+		}
+	}
+	file_oneof_proto_msgTypes[0].OneofWrappers = []interface{}{
+		(*OneOfRequest_Text)(nil),
+		(*OneOfRequest_Number)(nil),
+	}
+	file_oneof_proto_msgTypes[1].OneofWrappers = []interface{}{
+		(*OneOfReply_Text)(nil),
+		(*OneOfReply_Number)(nil),
+	}
+	type x struct{}
+	out := protoimpl.TypeBuilder{
+		File: protoimpl.DescBuilder{
+			GoPackagePath: reflect.TypeOf(x{}).PkgPath(),
+			RawDescriptor: file_oneof_proto_rawDesc,
+			NumEnums:      0,
+			NumMessages:   2,
+			NumExtensions: 0,
+			NumServices:   1,
+		},
+		GoTypes:           file_oneof_proto_goTypes,
+		DependencyIndexes: file_oneof_proto_depIdxs,
+		MessageInfos:      file_oneof_proto_msgTypes,
+	}.Build()
+	File_oneof_proto = out.File
+	file_oneof_proto_rawDesc = nil
+	file_oneof_proto_goTypes = nil
+	file_oneof_proto_depIdxs = nil
+}
diff --git a/examples/oneof/oneof.proto b/examples/oneof/oneof.proto
new file mode 100644
index 0000000..48ac0c2
--- /dev/null
+++ b/examples/oneof/oneof.proto
@@ -0,0 +1,22 @@
+syntax = "proto3";
+
+package oneof;
+option go_package = "go.mondoo.com/ranger-rpc/example/oneof";
+
+message OneOfRequest {
+  oneof options {
+    string text = 1;
+    int64 number = 2;
+  }
+}
+
+message OneOfReply {
+  oneof options {
+    string text = 1;
+    int64 number = 2;
+  }
+}
+
+service OneOf {
+  rpc Echo (OneOfRequest) returns (OneOfReply);
+}
diff --git a/examples/oneof/oneof.ranger.go b/examples/oneof/oneof.ranger.go
new file mode 100644
index 0000000..a35cce7
--- /dev/null
+++ b/examples/oneof/oneof.ranger.go
@@ -0,0 +1,111 @@
+// Code generated by protoc-gen-rangerrpc version DO NOT EDIT.
+// source: oneof.proto
+
+package oneof
+
+import (
+	"context"
+	"errors"
+	"net/http"
+	"net/url"
+	"strings"
+
+	ranger "go.mondoo.com/ranger-rpc"
+	"go.mondoo.com/ranger-rpc/metadata"
+	jsonpb "google.golang.org/protobuf/encoding/protojson"
+	pb "google.golang.org/protobuf/proto"
+)
+
+// service interface definition
+
+type OneOf interface {
+	Echo(context.Context, *OneOfRequest) (*OneOfReply, error)
+}
+
+// client implementation
+
+type OneOfClient struct {
+	ranger.Client
+	httpclient ranger.HTTPClient
+	prefix     string
+}
+
+func NewOneOfClient(addr string, client ranger.HTTPClient) (*OneOfClient, error) {
+	base, err := url.Parse(ranger.SanitizeUrl(addr))
+	if err != nil {
+		return nil, err
+	}
+
+	u, err := url.Parse("./OneOf")
+	if err != nil {
+		return nil, err
+	}
+
+	return &OneOfClient{
+		httpclient: client,
+		prefix:     base.ResolveReference(u).String(),
+	}, nil
+}
+func (c *OneOfClient) Echo(ctx context.Context, in *OneOfRequest) (*OneOfReply, error) {
+	out := new(OneOfReply)
+	err := c.DoClientRequest(ctx, c.httpclient, strings.Join([]string{c.prefix, "/Echo"}, ""), in, out)
+	return out, err
+}
+
+// server implementation
+
+type OneOfServerOption func(s *OneOfServer)
+
+func WithUnknownFieldsForOneOfServer() OneOfServerOption {
+	return func(s *OneOfServer) {
+		s.allowUnknownFields = true
+	}
+}
+
+func NewOneOfServer(handler OneOf, opts ...OneOfServerOption) http.Handler {
+	srv := &OneOfServer{
+		handler: handler,
+	}
+
+	for i := range opts {
+		opts[i](srv)
+	}
+
+	service := ranger.Service{
+		Name: "OneOf",
+		Methods: map[string]ranger.Method{
+			"Echo": srv.Echo,
+		},
+	}
+	return ranger.NewRPCServer(&service)
+}
+
+type OneOfServer struct {
+	handler            OneOf
+	allowUnknownFields bool
+}
+
+func (p *OneOfServer) Echo(ctx context.Context, reqBytes *[]byte) (pb.Message, error) {
+	var req OneOfRequest
+	var err error
+
+	md, ok := metadata.FromIncomingContext(ctx)
+	if !ok {
+		return nil, errors.New("could not access header")
+	}
+
+	switch md.First("Content-Type") {
+	case "application/protobuf", "application/octet-stream", "application/grpc+proto":
+		err = pb.Unmarshal(*reqBytes, &req)
+	default:
+		// handle case of empty object
+		if len(*reqBytes) > 0 {
+			err = jsonpb.UnmarshalOptions{DiscardUnknown: true}.Unmarshal(*reqBytes, &req)
+		}
+	}
+
+	if err != nil {
+		return nil, err
+	}
+	return p.handler.Echo(ctx, &req)
+}
diff --git a/examples/oneof/oneof_test.go b/examples/oneof/oneof_test.go
new file mode 100644
index 0000000..5034158
--- /dev/null
+++ b/examples/oneof/oneof_test.go
@@ -0,0 +1,115 @@
+package oneof
+
+import (
+	"bytes"
+	"context"
+	"io/ioutil"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	jsonpb "google.golang.org/protobuf/encoding/protojson"
+)
+
+// custom implementation
+type oneOfServerImpl struct{}
+
+func (s *oneOfServerImpl) Echo(ctx context.Context, in *OneOfRequest) (*OneOfReply, error) {
+	resp := &OneOfReply{}
+	if in.GetNumber() != 0 {
+		resp.Options = &OneOfReply_Number{
+			Number: in.GetNumber(),
+		}
+	}
+	if in.GetText() != "" {
+		resp.Options = &OneOfReply_Text{
+			Text: in.GetText(),
+		}
+	}
+	return resp, nil
+}
+
+func TestOneOf(t *testing.T) {
+	mux := http.NewServeMux()
+	mux.Handle("/api/", http.StripPrefix("/api", NewOneOfServer(&oneOfServerImpl{})))
+	server := httptest.NewServer(mux)
+	defer server.Close()
+
+	client, err := NewOneOfClient(server.URL+"/api/", &http.Client{})
+	assert.Nil(t, err)
+
+	t.Run("Echo text", func(t *testing.T) {
+		resp, err := client.Echo(context.Background(), &OneOfRequest{Options: &OneOfRequest_Text{Text: "Example"}})
+		require.Nil(t, err)
+		assert.Equal(t, "Example", resp.GetText())
+	})
+
+	t.Run("Echo number", func(t *testing.T) {
+		resp, err := client.Echo(context.Background(), &OneOfRequest{Options: &OneOfRequest_Number{Number: 42}})
+		require.Nil(t, err)
+		assert.Equal(t, int64(42), resp.GetNumber())
+	})
+}
+
+func TestOneOfJSON(t *testing.T) {
+	mux := http.NewServeMux()
+	mux.Handle("/", NewOneOfServer(&oneOfServerImpl{}))
+	server := httptest.NewServer(mux)
+	defer server.Close()
+
+	client := &http.Client{}
+
+	header := make(http.Header)
+	header.Set("Accept", "application/json")
+	header.Set("Content-Type", "application/json")
+
+	t.Run("Echo text", func(t *testing.T) {
+		in := &OneOfRequest{Options: &OneOfRequest_Text{Text: "Example"}}
+		buf, err := jsonpb.Marshal(in)
+		require.Nil(t, err)
+
+		reader := bytes.NewReader(buf)
+		req, err := http.NewRequest("POST", server.URL+"/OneOf/Echo", reader)
+		require.Nil(t, err)
+		req.Header = header
+
+		resp, err := client.Do(req)
+		require.Nil(t, err)
+		defer resp.Body.Close()
+		assert.Equal(t, "200 OK", resp.Status)
+
+		// check response
+		r := &OneOfReply{}
+		data, err := ioutil.ReadAll(resp.Body)
+		require.NoError(t, err)
+		err = jsonpb.Unmarshal(data, r)
+		assert.Nil(t, err)
+		assert.Equal(t, "Example", r.GetText())
+	})
+
+	t.Run("Echo number", func(t *testing.T) {
+		in := &OneOfRequest{Options: &OneOfRequest_Number{Number: 42}}
+		buf, err := jsonpb.Marshal(in)
+		assert.Nil(t, err)
+
+		reader := bytes.NewReader(buf)
+		req, err := http.NewRequest("POST", server.URL+"/OneOf/Echo", reader)
+		require.Nil(t, err)
+		req.Header = header
+
+		resp, err := client.Do(req)
+		require.Nil(t, err)
+		defer resp.Body.Close()
+		assert.Equal(t, "200 OK", resp.Status)
+
+		// check response
+		r := &OneOfReply{}
+		data, err := ioutil.ReadAll(resp.Body)
+		require.NoError(t, err)
+		err = jsonpb.Unmarshal(data, r)
+		assert.Nil(t, err)
+		assert.Equal(t, int64(42), r.GetNumber())
+	})
+}