diff --git a/addons/es/verifactu/verifactu.go b/addons/es/verifactu/verifactu.go
index 4ead855c..569e1b6a 100644
--- a/addons/es/verifactu/verifactu.go
+++ b/addons/es/verifactu/verifactu.go
@@ -17,6 +17,11 @@ const (
 const (
 	// StampQR contains the URL included in the QR code.
 	StampQR cbc.Key = "verifactu-qr"
+
+	// QRPrefix is the compulsory text to appear above the QR code.
+	QRPrefix string = "QR tributario:"
+	// QRSuffix is the compulsory text to appear below the QR code.
+	QRSuffix string = "VERI*FACTU"
 )
 
 func init() {
diff --git a/go.mod b/go.mod
index 7cfe15c1..ae8195dc 100644
--- a/go.mod
+++ b/go.mod
@@ -7,6 +7,7 @@ toolchain go1.22.5
 require (
 	cloud.google.com/go v0.110.2
 	github.com/Masterminds/semver/v3 v3.2.1
+	github.com/asaskevich/govalidator v0.0.0-20230301143203-a9d515a09cc2
 	github.com/google/go-cmp v0.6.0
 	github.com/google/uuid v1.6.0
 	github.com/imdario/mergo v0.3.16
@@ -23,7 +24,6 @@ require (
 )
 
 require (
-	github.com/asaskevich/govalidator v0.0.0-20230301143203-a9d515a09cc2 // indirect
 	github.com/bahlo/generic-list-go v0.2.0 // indirect
 	github.com/buger/jsonparser v1.1.1 // indirect
 	github.com/davecgh/go-spew v1.1.1 // indirect