diff --git a/pkg/api/annotation.go b/pkg/api/annotation.go
index 3678168515..fa7c6ac560 100644
--- a/pkg/api/annotation.go
+++ b/pkg/api/annotation.go
@@ -5,6 +5,7 @@ import (
 	"encoding/json"
 	"net/http"
 	"strconv"
+	"time"
 
 	"github.com/pyroscope-io/pyroscope/pkg/model"
 	"github.com/pyroscope-io/pyroscope/pkg/server/httputils"
@@ -42,9 +43,14 @@ func (h *AnnotationsHandler) CreateAnnotation(w http.ResponseWriter, r *http.Req
 		return
 	}
 
+	var timestamp time.Time
+	if params.Timestamp != 0 {
+		timestamp = attime.Parse(strconv.FormatInt(params.Timestamp, 10))
+	}
+
 	annotation, err := h.svc.CreateAnnotation(r.Context(), model.CreateAnnotation{
 		AppName:   params.AppName,
-		Timestamp: attime.Parse(strconv.FormatInt(params.Timestamp, 10)),
+		Timestamp: timestamp,
 		Content:   params.Content,
 	})
 	if err != nil {
diff --git a/pkg/api/annotation_test.go b/pkg/api/annotation_test.go
index f7a9fc94ec..8e4d765acb 100644
--- a/pkg/api/annotation_test.go
+++ b/pkg/api/annotation_test.go
@@ -8,17 +8,18 @@ import (
 	"time"
 
 	. "github.com/onsi/ginkgo/v2"
+	. "github.com/onsi/gomega"
 	"github.com/pyroscope-io/pyroscope/pkg/api/router"
 	"github.com/pyroscope-io/pyroscope/pkg/model"
 	"github.com/sirupsen/logrus"
 )
 
 type mockService struct {
-	createAnnotationResponse func() (*model.Annotation, error)
+	createAnnotationResponse func(params model.CreateAnnotation) (*model.Annotation, error)
 }
 
 func (m *mockService) CreateAnnotation(ctx context.Context, params model.CreateAnnotation) (*model.Annotation, error) {
-	return m.createAnnotationResponse()
+	return m.createAnnotationResponse(params)
 }
 
 var _ = Describe("AnnotationHandler", func() {
@@ -35,7 +36,7 @@ var _ = Describe("AnnotationHandler", func() {
 		When("all parameters are set", func() {
 			BeforeEach(func() {
 				svc = &mockService{
-					createAnnotationResponse: func() (*model.Annotation, error) {
+					createAnnotationResponse: func(params model.CreateAnnotation) (*model.Annotation, error) {
 						return &model.Annotation{
 							AppName:   "myApp",
 							Content:   "mycontent",
@@ -60,10 +61,39 @@ var _ = Describe("AnnotationHandler", func() {
 			})
 		})
 
+		When("timestamp is absent", func() {
+			It("it defaults to zero-value", func() {
+				svc = &mockService{
+					createAnnotationResponse: func(params model.CreateAnnotation) (m *model.Annotation, err error) {
+						// The service should receive a zero timestamp
+						Expect(params.Timestamp.IsZero()).To(BeTrue())
+
+						return &model.Annotation{
+							AppName:   "myApp",
+							Content:   "mycontent",
+							Timestamp: time.Unix(1662729099, 0),
+						}, nil
+					},
+				}
+
+				server = httptest.NewServer(newTestRouter(defaultUserCtx, router.Services{
+					Logger:             logrus.StandardLogger(),
+					AnnotationsService: svc,
+				}))
+
+				url := server.URL + "/annotations"
+
+				expectResponse(newRequest(http.MethodPost, url,
+					"annotation/create_request_no_timestamp.json"),
+					"annotation/create_response.json",
+					http.StatusCreated)
+			})
+		})
+
 		When("fields are invalid", func() {
 			BeforeEach(func() {
 				svc = &mockService{
-					createAnnotationResponse: func() (*model.Annotation, error) {
+					createAnnotationResponse: func(params model.CreateAnnotation) (*model.Annotation, error) {
 						return nil, model.ValidationError{errors.New("myerror")}
 					},
 				}
diff --git a/pkg/api/testdata/annotation/create_request_no_timestamp.json b/pkg/api/testdata/annotation/create_request_no_timestamp.json
new file mode 100644
index 0000000000..7506814067
--- /dev/null
+++ b/pkg/api/testdata/annotation/create_request_no_timestamp.json
@@ -0,0 +1,4 @@
+{
+  "appName": "myApp",
+  "content": "mycontent"
+}