diff --git a/go.mod b/go.mod
index 505be65..be69b7a 100644
--- a/go.mod
+++ b/go.mod
@@ -10,6 +10,7 @@ require (
 	github.com/gorilla/websocket v1.4.2
 	github.com/pkg/errors v0.9.1
 	github.com/status-im/keycard-go v0.3.3
+	github.com/tyler-smith/go-bip39 v1.0.1-0.20181017060643-dbb3b84ba2ef
 	go.uber.org/zap v1.27.0
 	golang.org/x/crypto v0.32.0
 	golang.org/x/text v0.21.0
diff --git a/go.sum b/go.sum
index 0c6d458..0d7872f 100644
--- a/go.sum
+++ b/go.sum
@@ -38,6 +38,8 @@ github.com/status-im/keycard-go v0.3.3 h1:qk/JHSkT9sMka+lVXrTOIVSgHIY7lDm46wrUqT
 github.com/status-im/keycard-go v0.3.3/go.mod h1:wlp8ZLbsmrF6g6WjugPAx+IzoLrkdf9+mHxBEeo3Hbg=
 github.com/stretchr/testify v1.8.4 h1:CcVxjf3Q8PM0mHUKJCdn+eZZtm5yQwehR5yeSVQQcUk=
 github.com/stretchr/testify v1.8.4/go.mod h1:sz/lmYIOXD/1dqDmKjjqLyZ2RngseejIcXlSw2iwfAo=
+github.com/tyler-smith/go-bip39 v1.0.1-0.20181017060643-dbb3b84ba2ef h1:wHSqTBrZW24CsNJDfeh9Ex6Pm0Rcpc7qrgKBiL44vF4=
+github.com/tyler-smith/go-bip39 v1.0.1-0.20181017060643-dbb3b84ba2ef/go.mod h1:sJ5fKU0s6JVwZjjcUEX2zFOnvq0ASQ2K9Zr6cf67kNs=
 go.uber.org/goleak v1.3.0 h1:2K3zAYmnTNqV73imy9J1T3WC+gmCePx2hEGkimedGto=
 go.uber.org/goleak v1.3.0/go.mod h1:CoHD4mav9JJNrW/WLlf7HGZPjdw8EucARQHekz1X6bE=
 go.uber.org/multierr v1.10.0 h1:S0h4aNzvfcFsC3dRF1jLoaov7oRaKqRGC/pUEJ2yvPQ=
diff --git a/pkg/session/service.go b/pkg/session/service.go
index d674969..ba5c17f 100644
--- a/pkg/session/service.go
+++ b/pkg/session/service.go
@@ -1,9 +1,6 @@
 package session
 
 import (
-	goerrors "errors"
-
-	"github.com/go-playground/validator/v10"
 	"github.com/pkg/errors"
 
 	"github.com/status-im/status-keycard-go/internal"
@@ -12,18 +9,8 @@ import (
 
 var (
 	errKeycardServiceNotStarted = errors.New("keycard service not started")
-	validate                    = validator.New()
 )
 
-func validateRequest(v interface{}) error {
-	err := validate.Struct(v)
-	if err != nil {
-		errs := err.(validator.ValidationErrors)
-		return goerrors.Join(errs)
-	}
-	return nil
-}
-
 type KeycardService struct {
 	keycardContext *internal.KeycardContextV2
 	simulateError  error
@@ -191,7 +178,7 @@ func (s *KeycardService) GenerateMnemonic(args *GenerateMnemonicRequest, reply *
 }
 
 type LoadMnemonicRequest struct {
-	Mnemonic   string `json:"mnemonic" validate:"required"`
+	Mnemonic   string `json:"mnemonic" validate:"required,mnemonic"`
 	Passphrase string `json:"passphrase"`
 }
 
diff --git a/pkg/session/validate.go b/pkg/session/validate.go
new file mode 100644
index 0000000..1f829c0
--- /dev/null
+++ b/pkg/session/validate.go
@@ -0,0 +1,35 @@
+package session
+
+import (
+	goerrors "errors"
+
+	"github.com/go-playground/validator/v10"
+	"github.com/tyler-smith/go-bip39"
+)
+
+var (
+	validate = validator.New()
+)
+
+func init() {
+	// Register the custom validation function
+	err := validate.RegisterValidation("mnemonic", isMnemonic)
+	if err != nil {
+		panic(err)
+	}
+}
+
+func validateRequest(v interface{}) error {
+	err := validate.Struct(v)
+	if err != nil {
+		errs := err.(validator.ValidationErrors)
+		return goerrors.Join(errs)
+	}
+	return nil
+}
+
+// Custom validation function to check if a string is a list of space-separated words
+func isMnemonic(fl validator.FieldLevel) bool {
+	mnemonic := fl.Field().String()
+	return bip39.IsMnemonicValid(mnemonic)
+}