diff --git a/pkg/handler/cors_test.go b/pkg/handler/cors_test.go
index 1979f546a..39b8c1722 100644
--- a/pkg/handler/cors_test.go
+++ b/pkg/handler/cors_test.go
@@ -21,7 +21,7 @@ func TestCORS(t *testing.T) {
 			},
 			Code: http.StatusOK,
 			ResHeader: map[string]string{
-				"Access-Control-Allow-Headers": "Authorization, Origin, X-Requested-With, X-Request-ID, X-HTTP-Method-Override, Content-Type, Upload-Length, Upload-Offset, Tus-Resumable, Upload-Metadata, Upload-Defer-Length, Upload-Concat",
+				"Access-Control-Allow-Headers": "Authorization, Origin, X-Requested-With, X-Request-ID, X-HTTP-Method-Override, Content-Type, Upload-Length, Upload-Offset, Tus-Resumable, Upload-Metadata, Upload-Defer-Length, Upload-Concat, Upload-Incomplete",
 				"Access-Control-Allow-Methods": "POST, HEAD, PATCH, OPTIONS, GET, DELETE",
 				"Access-Control-Max-Age":       "86400",
 				"Access-Control-Allow-Origin":  "tus.io",
@@ -43,7 +43,7 @@ func TestCORS(t *testing.T) {
 			},
 			Code: http.StatusOK,
 			ResHeader: map[string]string{
-				"Access-Control-Allow-Headers": "Authorization, Origin, X-Requested-With, X-Request-ID, X-HTTP-Method-Override, Content-Type, Upload-Length, Upload-Offset, Tus-Resumable, Upload-Metadata, Upload-Defer-Length, Upload-Concat",
+				"Access-Control-Allow-Headers": "Authorization, Origin, X-Requested-With, X-Request-ID, X-HTTP-Method-Override, Content-Type, Upload-Length, Upload-Offset, Tus-Resumable, Upload-Metadata, Upload-Defer-Length, Upload-Concat, Upload-Incomplete",
 				"Access-Control-Allow-Methods": "POST, HEAD, PATCH, OPTIONS",
 				"Access-Control-Max-Age":       "86400",
 				"Access-Control-Allow-Origin":  "tus.io",
@@ -64,7 +64,7 @@ func TestCORS(t *testing.T) {
 			},
 			Code: http.StatusMethodNotAllowed,
 			ResHeader: map[string]string{
-				"Access-Control-Expose-Headers": "Upload-Offset, Location, Upload-Length, Tus-Version, Tus-Resumable, Tus-Max-Size, Tus-Extension, Upload-Metadata, Upload-Defer-Length, Upload-Concat",
+				"Access-Control-Expose-Headers": "Upload-Offset, Location, Upload-Length, Tus-Version, Tus-Resumable, Tus-Max-Size, Tus-Extension, Upload-Metadata, Upload-Defer-Length, Upload-Concat, Upload-Incomplete",
 				"Access-Control-Allow-Origin":   "tus.io",
 			},
 		}).Run(handler, t)
diff --git a/pkg/handler/head_test.go b/pkg/handler/head_test.go
index b5c83bba2..c055400ec 100644
--- a/pkg/handler/head_test.go
+++ b/pkg/handler/head_test.go
@@ -146,4 +146,107 @@ func TestHead(t *testing.T) {
 			},
 		}).Run(handler, t)
 	})
+
+	SubTest(t, "ExperimentalProtocol", func(t *testing.T, _ *MockFullDataStore, _ *StoreComposer) {
+		SubTest(t, "IncompleteUpload", func(t *testing.T, store *MockFullDataStore, composer *StoreComposer) {
+			ctrl := gomock.NewController(t)
+			defer ctrl.Finish()
+			upload := NewMockFullUpload(ctrl)
+
+			gomock.InOrder(
+				store.EXPECT().GetUpload(context.Background(), "yes").Return(upload, nil),
+				upload.EXPECT().GetInfo(context.Background()).Return(FileInfo{
+					SizeIsDeferred: false,
+					Size:           10,
+					Offset:         5,
+				}, nil),
+			)
+
+			handler, _ := NewHandler(Config{
+				StoreComposer:              composer,
+				EnableExperimentalProtocol: true,
+			})
+
+			(&httpTest{
+				Method: "HEAD",
+				URL:    "yes",
+				ReqHeader: map[string]string{
+					"Upload-Draft-Interop-Version": "3",
+				},
+				Code: http.StatusNoContent,
+				ResHeader: map[string]string{
+					"Upload-Draft-Interop-Version": "3",
+					"Upload-Incomplete":            "?1",
+					"Upload-Offset":                "5",
+				},
+			}).Run(handler, t)
+		})
+
+		SubTest(t, "CompleteUpload", func(t *testing.T, store *MockFullDataStore, composer *StoreComposer) {
+			ctrl := gomock.NewController(t)
+			defer ctrl.Finish()
+			upload := NewMockFullUpload(ctrl)
+
+			gomock.InOrder(
+				store.EXPECT().GetUpload(context.Background(), "yes").Return(upload, nil),
+				upload.EXPECT().GetInfo(context.Background()).Return(FileInfo{
+					SizeIsDeferred: false,
+					Size:           10,
+					Offset:         10,
+				}, nil),
+			)
+
+			handler, _ := NewHandler(Config{
+				StoreComposer:              composer,
+				EnableExperimentalProtocol: true,
+			})
+
+			(&httpTest{
+				Method: "HEAD",
+				URL:    "yes",
+				ReqHeader: map[string]string{
+					"Upload-Draft-Interop-Version": "3",
+				},
+				Code: http.StatusNoContent,
+				ResHeader: map[string]string{
+					"Upload-Draft-Interop-Version": "3",
+					"Upload-Incomplete":            "?0",
+					"Upload-Offset":                "10",
+				},
+			}).Run(handler, t)
+		})
+
+		SubTest(t, "DeferredLength", func(t *testing.T, store *MockFullDataStore, composer *StoreComposer) {
+			ctrl := gomock.NewController(t)
+			defer ctrl.Finish()
+			upload := NewMockFullUpload(ctrl)
+
+			gomock.InOrder(
+				store.EXPECT().GetUpload(context.Background(), "yes").Return(upload, nil),
+				upload.EXPECT().GetInfo(context.Background()).Return(FileInfo{
+					SizeIsDeferred: true,
+					Offset:         5,
+				}, nil),
+			)
+
+			handler, _ := NewHandler(Config{
+				StoreComposer:              composer,
+				EnableExperimentalProtocol: true,
+			})
+
+			(&httpTest{
+				Method: "HEAD",
+				URL:    "yes",
+				ReqHeader: map[string]string{
+					"Upload-Draft-Interop-Version": "3",
+				},
+				Code: http.StatusNoContent,
+				ResHeader: map[string]string{
+					"Upload-Draft-Interop-Version": "3",
+					"Upload-Incomplete":            "?1",
+					"Upload-Offset":                "5",
+				},
+			}).Run(handler, t)
+		})
+	})
 }
diff --git a/pkg/handler/patch_test.go b/pkg/handler/patch_test.go
index 3329a4524..6dd1690b0 100644
--- a/pkg/handler/patch_test.go
+++ b/pkg/handler/patch_test.go
@@ -683,4 +683,161 @@ func TestPatch(t *testing.T) {
 			ResBody: "an error while reading the body\n",
 		}).Run(handler, t)
 	})
+
+	SubTest(t, "ExperimentalProtocol", func(t *testing.T, _ *MockFullDataStore, _ *StoreComposer) {
+		SubTest(t, "CompleteUploadWithKnownSize", func(t *testing.T, store *MockFullDataStore, composer *StoreComposer) {
+			ctrl := gomock.NewController(t)
+			defer ctrl.Finish()
+			upload := NewMockFullUpload(ctrl)
+
+			gomock.InOrder(
+				store.EXPECT().GetUpload(context.Background(), "yes").Return(upload, nil),
+				upload.EXPECT().GetInfo(context.Background()).Return(FileInfo{
+					ID:             "yes",
+					Offset:         5,
+					Size:           10,
+					SizeIsDeferred: false,
+				}, nil),
+				upload.EXPECT().WriteChunk(context.Background(), int64(5), NewReaderMatcher("hello")).Return(int64(5), nil),
+				upload.EXPECT().FinishUpload(context.Background()),
+			)
+
+			handler, _ := NewHandler(Config{
+				StoreComposer:              composer,
+				EnableExperimentalProtocol: true,
+			})
+
+			(&httpTest{
+				Method: "PATCH",
+				URL:    "yes",
+				ReqHeader: map[string]string{
+					"Upload-Draft-Interop-Version": "3",
+					"Upload-Offset":                "5",
+					"Upload-Incomplete":            "?0",
+				},
+				ReqBody: strings.NewReader("hello"),
+				Code:    http.StatusNoContent,
+				ResHeader: map[string]string{
+					"Upload-Offset": "10",
+				},
+			}).Run(handler, t)
+		})
+		SubTest(t, "CompleteUploadWithUnknownSize", func(t *testing.T, store *MockFullDataStore, composer *StoreComposer) {
+			ctrl := gomock.NewController(t)
+			defer ctrl.Finish()
+			upload := NewMockFullUpload(ctrl)
+
+			gomock.InOrder(
+				store.EXPECT().GetUpload(context.Background(), "yes").Return(upload, nil),
+				upload.EXPECT().GetInfo(context.Background()).Return(FileInfo{
+					ID:             "yes",
+					Offset:         5,
+					Size:           0,
+					SizeIsDeferred: true,
+				}, nil),
+				upload.EXPECT().WriteChunk(context.Background(), int64(5), NewReaderMatcher("hello")).Return(int64(5), nil),
+				upload.EXPECT().GetInfo(context.Background()).Return(FileInfo{
+					ID:             "yes",
+					Offset:         10,
+					Size:           0,
+					SizeIsDeferred: true,
+				}, nil),
+				store.EXPECT().AsLengthDeclarableUpload(upload).Return(upload),
+				upload.EXPECT().DeclareLength(context.Background(), int64(10)),
+				upload.EXPECT().FinishUpload(context.Background()),
+			)
+
+			handler, _ := NewHandler(Config{
+				StoreComposer:              composer,
+				EnableExperimentalProtocol: true,
+			})
+
+			(&httpTest{
+				Method: "PATCH",
+				URL:    "yes",
+				ReqHeader: map[string]string{
+					"Upload-Draft-Interop-Version": "3",
+					"Upload-Offset":                "5",
+					"Upload-Incomplete":            "?0",
+				},
+				ReqBody: strings.NewReader("hello"),
+				Code:    http.StatusNoContent,
+				ResHeader: map[string]string{
+					"Upload-Offset": "10",
+				},
+			}).Run(handler, t)
+		})
+		SubTest(t, "ContinueUploadWithKnownSize", func(t *testing.T, store *MockFullDataStore, composer *StoreComposer) {
+			ctrl := gomock.NewController(t)
+			defer ctrl.Finish()
+			upload := NewMockFullUpload(ctrl)
+
+			gomock.InOrder(
+				store.EXPECT().GetUpload(context.Background(), "yes").Return(upload, nil),
+				upload.EXPECT().GetInfo(context.Background()).Return(FileInfo{
+					ID:             "yes",
+					Offset:         5,
+					Size:           10,
+					SizeIsDeferred: false,
+				}, nil),
+				upload.EXPECT().WriteChunk(context.Background(), int64(5), NewReaderMatcher("hel")).Return(int64(3), nil),
+			)
+
+			handler, _ := NewHandler(Config{
+				StoreComposer:              composer,
+				EnableExperimentalProtocol: true,
+			})
+
+			(&httpTest{
+				Method: "PATCH",
+				URL:    "yes",
+				ReqHeader: map[string]string{
+					"Upload-Draft-Interop-Version": "3",
+					"Upload-Offset":                "5",
+					"Upload-Incomplete":            "?1",
+				},
+				ReqBody: strings.NewReader("hel"),
+				Code:    http.StatusNoContent,
+				ResHeader: map[string]string{
+					"Upload-Offset": "8",
+				},
+			}).Run(handler, t)
+		})
+		SubTest(t, "ContinueUploadWithUnknownSize", func(t *testing.T, store *MockFullDataStore, composer *StoreComposer) {
+			ctrl := gomock.NewController(t)
+			defer ctrl.Finish()
+			upload := NewMockFullUpload(ctrl)
+
+			gomock.InOrder(
+				store.EXPECT().GetUpload(context.Background(), "yes").Return(upload, nil),
+				upload.EXPECT().GetInfo(context.Background()).Return(FileInfo{
+					ID:             "yes",
+					Offset:         5,
+					Size:           0,
+					SizeIsDeferred: true,
+				}, nil),
+				upload.EXPECT().WriteChunk(context.Background(), int64(5), NewReaderMatcher("hel")).Return(int64(3), nil),
+			)
+
+			handler, _ := NewHandler(Config{
+				StoreComposer:              composer,
+				EnableExperimentalProtocol: true,
+			})
+
+			(&httpTest{
+				Method: "PATCH",
+				URL:    "yes",
+				ReqHeader: map[string]string{
+					"Upload-Draft-Interop-Version": "3",
+					"Upload-Offset":                "5",
+					"Upload-Incomplete":            "?1",
+				},
+				ReqBody: strings.NewReader("hel"),
+				Code:    http.StatusNoContent,
+				ResHeader: map[string]string{
+					"Upload-Offset": "8",
+				},
+			}).Run(handler, t)
+		})
+	})
 }
diff --git a/pkg/handler/post_test.go b/pkg/handler/post_test.go
index 12425c276..43f5f70d2 100644
--- a/pkg/handler/post_test.go
+++ b/pkg/handler/post_test.go
@@ -544,4 +544,117 @@ func TestPost(t *testing.T) {
 			}).Run(handler, t)
 		})
 	})
+
+	SubTest(t, "ExperimentalProtocol", func(t *testing.T, _ *MockFullDataStore, _ *StoreComposer) {
+		SubTest(t, "CompleteUpload", func(t *testing.T, store *MockFullDataStore, composer *StoreComposer) {
+			ctrl := gomock.NewController(t)
+			defer ctrl.Finish()
+			locker := NewMockFullLocker(ctrl)
+			lock := NewMockFullLock(ctrl)
+			upload := NewMockFullUpload(ctrl)
+
+			gomock.InOrder(
+				store.EXPECT().NewUpload(context.Background(), FileInfo{
+					SizeIsDeferred: false,
+					Size:           11,
+					MetaData: map[string]string{
+						"filename": "hello.txt",
+						"filetype": "text/plain",
+					},
+				}).Return(upload, nil),
+				upload.EXPECT().GetInfo(context.Background()).Return(FileInfo{
+					ID:             "foo",
+					SizeIsDeferred: false,
+					Size:           11,
+					MetaData: map[string]string{
+						"filename": "hello.txt",
+						"filetype": "text/plain",
+					},
+				}, nil),
+				locker.EXPECT().NewLock("foo").Return(lock, nil),
+				lock.EXPECT().Lock().Return(nil),
+				upload.EXPECT().WriteChunk(context.Background(), int64(0), NewReaderMatcher("hello world")).Return(int64(11), nil),
+				upload.EXPECT().FinishUpload(context.Background()).Return(nil),
+				lock.EXPECT().Unlock().Return(nil),
+			)
+
+			composer = NewStoreComposer()
+			composer.UseCore(store)
+			composer.UseLocker(locker)
+
+			handler, _ := NewHandler(Config{
+				StoreComposer:              composer,
+				BasePath:                   "/files/",
+				EnableExperimentalProtocol: true,
+			})
+
+			(&httpTest{
+				Method: "POST",
+				ReqHeader: map[string]string{
+					"Upload-Draft-Interop-Version": "3",
+					"Upload-Incomplete":            "?0",
+					"Content-Type":                 "text/plain; charset=utf-8",
+					"Content-Disposition":          "attachment; filename=hello.txt",
+				},
+				ReqBody: strings.NewReader("hello world"),
+				// TODO: httptest.Recorder only captures the first informational response, so must expect a 104 and not a 201 here.
+				Code: 104,
+				ResHeader: map[string]string{
+					"Upload-Draft-Interop-Version": "3",
+					"Location":                     "http://tus.io/files/foo",
+					"Upload-Offset":                "11",
+				},
+			}).Run(handler, t)
+		})
+
+		SubTest(t, "IncompleteUpload", func(t *testing.T, store *MockFullDataStore, composer *StoreComposer) {
+			ctrl := gomock.NewController(t)
+			defer ctrl.Finish()
+			locker := NewMockFullLocker(ctrl)
+			lock := NewMockFullLock(ctrl)
+			upload := NewMockFullUpload(ctrl)
+
+			gomock.InOrder(
+				store.EXPECT().NewUpload(context.Background(), FileInfo{
+					SizeIsDeferred: true,
+					MetaData:       map[string]string{},
+				}).Return(upload, nil),
+				upload.EXPECT().GetInfo(context.Background()).Return(FileInfo{
+					ID:             "foo",
+					SizeIsDeferred: true,
+				}, nil),
+				locker.EXPECT().NewLock("foo").Return(lock, nil),
+				lock.EXPECT().Lock().Return(nil),
+				upload.EXPECT().WriteChunk(context.Background(), int64(0), NewReaderMatcher("hello world")).Return(int64(11), nil),
+				lock.EXPECT().Unlock().Return(nil),
+			)
+
+			composer = NewStoreComposer()
+			composer.UseCore(store)
+			composer.UseLocker(locker)
+			composer.UseLengthDeferrer(store)
+
+			handler, _ := NewHandler(Config{
+				StoreComposer:              composer,
+				BasePath:                   "/files/",
+				EnableExperimentalProtocol: true,
+			})
+
+			(&httpTest{
+				Method: "POST",
+				ReqHeader: map[string]string{
+					"Upload-Draft-Interop-Version": "3",
+					"Upload-Incomplete":            "?1",
+				},
+				ReqBody: strings.NewReader("hello world"),
+				// TODO: httptest.Recorder only captures the first informational response, so must expect a 104 and not a 201 here.
+				Code: 104,
+				ResHeader: map[string]string{
+					"Upload-Draft-Interop-Version": "3",
+					"Location":                     "http://tus.io/files/foo",
+					"Upload-Offset":                "11",
+				},
+			}).Run(handler, t)
+		})
+	})
 }