diff --git a/backend/cmd/server/main.go b/backend/cmd/server/main.go
index 9b829f0..54474c7 100644
--- a/backend/cmd/server/main.go
+++ b/backend/cmd/server/main.go
@@ -8,7 +8,7 @@ import (
 
 func main() {
 
-	err, config := config.LoadApplicationConfig()
+	err, _ := config.LoadApplicationConfig()
 
 	if err != nil {
 		log.Fatalln(err)
diff --git a/backend/cmd/server/main_test.go b/backend/cmd/server/main_test.go
index ad00cff..7ef862f 100644
--- a/backend/cmd/server/main_test.go
+++ b/backend/cmd/server/main_test.go
@@ -4,17 +4,17 @@ import (
 	"fmt"
 	"testing"
 
-	"github.com/vaultdrop/backend/entities"
+	"github.com/vaultdrop/backend/models"
 )
 
 func TestUserCreation(t *testing.T) {
 
-	err, userAntoine := entities.NewUser("antoine")
+	err, userAntoine := models.NewUser("antoine")
 	if err != nil {
 		t.Errorf(`Error creating antoine user %v`, err)
 	}
 
-	err, userBob := entities.NewUser("bob")
+	err, userBob := models.NewUser("bob")
 	if err != nil {
 		t.Errorf(`Error creating bob user %v`, err)
 	}
@@ -25,16 +25,16 @@ func TestUserCreation(t *testing.T) {
 
 func TestCreateDocument(t *testing.T) {
 
-	err, document := entities.NewDocument("paper.pdf", entities.FILE)
+	err, document := models.NewDocument("paper.pdf", models.FILE, 1)
 	if err != nil {
 		t.Errorf(`Error creating document %v`, err)
 	}
 
-	err, directory := entities.NewDocument("bob", entities.DIRECTORY)
+	err, directory := models.NewDocument("bob", models.DIRECTORY, 1)
 	if err != nil {
 		t.Errorf(`Error creating bob directory %v`, err)
 	}
 
 	fmt.Println(document, directory)
 
-}
+}
\ No newline at end of file
diff --git a/backend/handlers/.gitkeep b/backend/handlers/.gitkeep
new file mode 100644
index 0000000..4dff090
--- /dev/null
+++ b/backend/handlers/.gitkeep
@@ -0,0 +1 @@
+# Gin HTTP handlers land here (bind the routes, current 501 stubs).
\ No newline at end of file
diff --git a/backend/models/clients.go b/backend/models/clients.go
index 24e51eb..6e6b68a 100644
--- a/backend/models/clients.go
+++ b/backend/models/clients.go
@@ -1,4 +1,4 @@
-package entities
+package models
 
 import "fmt"
 
@@ -13,7 +13,7 @@ func NewClient(clientVersion int) (error, Client) {
 	isCompatible := ServerClientIsCompatibleWithClient(clientVersion)
 
 	if !isCompatible {
-		return fmt.Errorf("You client version %n is not compatible with the server verison %n", clientVersion, SERVER_VERSION), nil
+		return fmt.Errorf("You client version %d is not compatible with the server verison %d", clientVersion, SERVER_VERSION), nil
 	}
 
 	client := ClientVerisonOne{
diff --git a/backend/models/documents.go b/backend/models/documents.go
index 6048da9..d3efc73 100644
--- a/backend/models/documents.go
+++ b/backend/models/documents.go
@@ -1,4 +1,4 @@
-package entities
+package models
 
 import (
 	"fmt"
diff --git a/backend/models/entities.go b/backend/models/entities.go
index 1899b98..2640e7f 100644
--- a/backend/models/entities.go
+++ b/backend/models/entities.go
@@ -1 +1 @@
-package entities
+package models
diff --git a/backend/models/users.go b/backend/models/users.go
index f48ec6b..bcab8ff 100644
--- a/backend/models/users.go
+++ b/backend/models/users.go
@@ -1,4 +1,4 @@
-package entities
+package models
 
 type User struct {
 	Username string
diff --git a/backend/ocr/engine.go b/backend/ocr/engine.go
new file mode 100644
index 0000000..3317f4f
--- /dev/null
+++ b/backend/ocr/engine.go
@@ -0,0 +1,10 @@
+package ocr
+
+import "context"
+
+// Engine extracts text from a document (image or PDF) located at filePath.
+// The V1 implementation is a Tesseract system call (OCR_LANG, défaut fra+eng);
+// swapping to a remote service later only changes the injection point.
+type Engine interface {
+	ExtractText(ctx context.Context, filePath string, lang string) (string, error)
+}
\ No newline at end of file
diff --git a/backend/repository/.gitkeep b/backend/repository/.gitkeep
new file mode 100644
index 0000000..a130b38
--- /dev/null
+++ b/backend/repository/.gitkeep
@@ -0,0 +1 @@
+# Postgres repositories land here (golang-migrate migrations, lib/pq).
\ No newline at end of file
diff --git a/backend/service/folders.go b/backend/service/folders.go
index 2903e3b..367ebfe 100644
--- a/backend/service/folders.go
+++ b/backend/service/folders.go
@@ -1,10 +1,10 @@
-package services
+package service
 
-import "github.com/vaultdrop/backend/entities"
+import "github.com/vaultdrop/backend/models"
 
-func (s *Services) CreateFolder(folderName string, destination *entities.Document) (error, *entities.Document) {
+func (s *Services) CreateFolder(folderName string, destination *models.Document) (error, *models.Document) {
 
-	err, directory := entities.NewDocument(folderName, entities.DIRECTORY)
+	err, directory := models.NewDocument(folderName, models.DIRECTORY, 1)
 	if err != nil {
 		return err, nil
 	}
diff --git a/backend/service/move.go b/backend/service/move.go
index 383c386..0e9ec85 100644
--- a/backend/service/move.go
+++ b/backend/service/move.go
@@ -1,18 +1,18 @@
-package services
+package service
 
 import (
 	"fmt"
 
-	"github.com/vaultdrop/backend/entities"
+	"github.com/vaultdrop/backend/models"
 )
 
-func (s *Services) MoveDocumentIntoDocument(from *entities.Document, to *entities.Document) error {
+func (s *Services) MoveDocumentIntoDocument(from *models.Document, to *models.Document) error {
 
-	if from.DocumentUUID == nil {
-		return fmt.Errorf(entities.ERROR_DOCUMENT_NOT_PERCISTED)
+	if from.UUID == nil {
+		return fmt.Errorf(models.ERROR_DOCUMENT_NOT_PERCISTED)
 	}
 
-	if to.DocumentType != entities.DIRECTORY {
+	if to.Type != models.DIRECTORY {
 		return fmt.Errorf("The destination document must be a directory")
 	}
 
@@ -26,7 +26,7 @@ func (s *Services) MoveDocumentIntoDocument(from *entities.Document, to *entitie
 
 	// Check if document exist and move the document into document if is directory
 
-	fmt.Println("To implement move to ", to.DocumentUUID)
+	fmt.Println("To implement move to ", to.UUID)
 
 	return nil
 
diff --git a/backend/service/move_test.go b/backend/service/move_test.go
index 3c0e4ab..a1f1089 100644
--- a/backend/service/move_test.go
+++ b/backend/service/move_test.go
@@ -1,24 +1,24 @@
-package services
+package service
 
 import (
 	"testing"
 
-	"github.com/vaultdrop/backend/entities"
+	"github.com/vaultdrop/backend/models"
 )
 
 func TestMoveDocument(t *testing.T) {
 
-	err, userAntoine := entities.NewUser("antoine")
+	err, userAntoine := models.NewUser("antoine")
 	if err != nil {
 		t.Errorf(`Error creating antoine user %v`, err)
 	}
 
 	fakeUUID := "dsqdsq"
-	err, document := entities.NewDocument("test.pdf", entities.FILE)
-	document.DocumentUUID = &fakeUUID
+	err, document := models.NewDocument("test.pdf", models.FILE, 1)
+	document.UUID = &fakeUUID
 
-	err, folder := entities.NewDocument("orga", entities.DIRECTORY)
-	folder.DocumentUUID = &fakeUUID
+	err, folder := models.NewDocument("orga", models.DIRECTORY, 1)
+	folder.UUID = &fakeUUID
 
 	service := New(userAntoine)
 
@@ -32,14 +32,14 @@ func TestMoveDocument(t *testing.T) {
 
 func TestMoveDocumentToAFile(t *testing.T) {
 
-	err, userAntoine := entities.NewUser("antoine")
+	err, userAntoine := models.NewUser("antoine")
 	if err != nil {
 		t.Errorf(`Error creating antoine user %v`, err)
 	}
 
-	err, document := entities.NewDocument("test.pdf", entities.FILE)
+	err, document := models.NewDocument("test.pdf", models.FILE, 1)
 
-	err, notAFolder := entities.NewDocument("orga", entities.FILE)
+	err, notAFolder := models.NewDocument("orga", models.FILE, 1)
 
 	service := New(userAntoine)
 
@@ -49,4 +49,4 @@ func TestMoveDocumentToAFile(t *testing.T) {
 		t.Error(err)
 	}
 
-}
+}
\ No newline at end of file
diff --git a/backend/service/services.go b/backend/service/services.go
index b9db9b5..f00b11d 100644
--- a/backend/service/services.go
+++ b/backend/service/services.go
@@ -1,14 +1,12 @@
-package services
+package service
 
-import "github.com/vaultdrop/backend/entities"
-
-// import "github.com/vaultdrop/backend/entities"
+import "github.com/vaultdrop/backend/models"
 
 type Services struct {
-	ConnectedUser *entities.User
+	ConnectedUser *models.User
 }
 
-func New(connectedUser *entities.User) *Services {
+func New(connectedUser *models.User) *Services {
 
 	return &Services{
 		ConnectedUser: connectedUser,
@@ -16,18 +14,18 @@ func New(connectedUser *entities.User) *Services {
 
 }
 
-func UserCanReadDocument(connectedUser *entities.User, document *entities.Document) (bool, string) {
+func UserCanReadDocument(connectedUser *models.User, document *models.Document) (bool, string) {
 	return true, ""
 }
 
-func UserCanEditDocument(connectedUser *entities.User, document *entities.Document) (bool, string) {
+func UserCanEditDocument(connectedUser *models.User, document *models.Document) (bool, string) {
 	return true, ""
 }
 
-func UserCanDeleteDocument(connectedUser *entities.User, document *entities.Document) (bool, string) {
+func UserCanDeleteDocument(connectedUser *models.User, document *models.Document) (bool, string) {
 	return true, ""
 }
 
-func UserCanCreateDocument(connectedUser *entities.User, document *entities.Document) (bool, string) {
+func UserCanCreateDocument(connectedUser *models.User, document *models.Document) (bool, string) {
 	return true, ""
 }
diff --git a/backend/service/upload.go b/backend/service/upload.go
index 448a905..ae3af36 100644
--- a/backend/service/upload.go
+++ b/backend/service/upload.go
@@ -1,18 +1,18 @@
-package services
+package service
 
 import (
 	"fmt"
 
-	"github.com/vaultdrop/backend/entities"
+	"github.com/vaultdrop/backend/models"
 )
 
-func (s *Services) UploadDocument(file *string, destination *entities.Document) error {
+func (s *Services) UploadDocument(file *string, destination *models.Document) error {
 
 	if canEdit, _ := UserCanEditDocument(s.ConnectedUser, destination); !canEdit {
 		return fmt.Errorf("Can not edit")
 	}
 
-	entities.NewDocument("test", entities.FILE)
+	models.NewDocument("test", models.FILE, 1)
 
 	return nil
 
diff --git a/backend/uploads/.gitkeep b/backend/uploads/.gitkeep
new file mode 100644
index 0000000..083694e
--- /dev/null
+++ b/backend/uploads/.gitkeep
@@ -0,0 +1 @@
+# Uploaded files (MAX_FILE_SIZE_MB = 50 by default).
\ No newline at end of file