diff --git a/pkg/africastalking/input.go b/pkg/africastalking/input.go
index 25c9ce5..db5050c 100644
--- a/pkg/africastalking/input.go
+++ b/pkg/africastalking/input.go
@@ -7,6 +7,10 @@ import (
 )
 
 func ConcatText(session *core.Session) string {
+	if session == nil {
+		return ""
+	}
+
 	inputs := make([]string, 0)
 	for _, step := range session.Steps {
 		inputs = append(inputs, step.Text)
diff --git a/pkg/africastalking/input_test.go b/pkg/africastalking/input_test.go
index db9de31..e4b3b20 100644
--- a/pkg/africastalking/input_test.go
+++ b/pkg/africastalking/input_test.go
@@ -8,6 +8,19 @@ import (
 	"github.com/stretchr/testify/assert"
 )
 
+func TestConcatTextWithNilSession(t *testing.T) {
+	got := africastalking.ConcatText(nil)
+	assert.Equal(t, "", got)
+}
+
+func TestConcatTextWithNilSteps(t *testing.T) {
+	got := africastalking.ConcatText(&core.Session{
+		Steps: nil,
+	})
+
+	assert.Equal(t, "", got)
+}
+
 func TestConcatText(t *testing.T) {
 	got := africastalking.ConcatText(&core.Session{
 		Steps: []*core.Step{