diff --git a/backend/src/Squidex.Domain.Apps.Entities/Apps/Commands/CreateApp.cs b/backend/src/Squidex.Domain.Apps.Entities/Apps/Commands/CreateApp.cs
index 5a97ddd7f..89a491519 100644
--- a/backend/src/Squidex.Domain.Apps.Entities/Apps/Commands/CreateApp.cs
+++ b/backend/src/Squidex.Domain.Apps.Entities/Apps/Commands/CreateApp.cs
@@ -13,7 +13,7 @@ namespace Squidex.Domain.Apps.Entities.Apps.Commands
     {
         public string Name { get; set; }
 
-        public string Template { get; set; }
+        public string? Template { get; set; }
 
         public CreateApp()
         {
diff --git a/backend/src/Squidex.Domain.Apps.Entities/Apps/Commands/UpdateClient.cs b/backend/src/Squidex.Domain.Apps.Entities/Apps/Commands/UpdateClient.cs
index e5808d6eb..854242be3 100644
--- a/backend/src/Squidex.Domain.Apps.Entities/Apps/Commands/UpdateClient.cs
+++ b/backend/src/Squidex.Domain.Apps.Entities/Apps/Commands/UpdateClient.cs
@@ -13,6 +13,6 @@ namespace Squidex.Domain.Apps.Entities.Apps.Commands
 
         public string Name { get; set; }
 
-        public string Role { get; set; }
+        public string? Role { get; set; }
     }
 }
diff --git a/backend/src/Squidex.Domain.Apps.Entities/Assets/Commands/AnnotateAsset.cs b/backend/src/Squidex.Domain.Apps.Entities/Assets/Commands/AnnotateAsset.cs
index 4d9059168..5ef8c77e0 100644
--- a/backend/src/Squidex.Domain.Apps.Entities/Assets/Commands/AnnotateAsset.cs
+++ b/backend/src/Squidex.Domain.Apps.Entities/Assets/Commands/AnnotateAsset.cs
@@ -11,9 +11,9 @@ namespace Squidex.Domain.Apps.Entities.Assets.Commands
 {
     public sealed class AnnotateAsset : AssetCommand
     {
-        public string FileName { get; set; }
+        public string? FileName { get; set; }
 
-        public string Slug { get; set; }
+        public string? Slug { get; set; }
 
         public HashSet<string> Tags { get; set; }
     }
diff --git a/backend/src/Squidex/Areas/Api/Controllers/Apps/Models/AppDto.cs b/backend/src/Squidex/Areas/Api/Controllers/Apps/Models/AppDto.cs
index 8192b050b..831a3b3a7 100644
--- a/backend/src/Squidex/Areas/Api/Controllers/Apps/Models/AppDto.cs
+++ b/backend/src/Squidex/Areas/Api/Controllers/Apps/Models/AppDto.cs
@@ -39,12 +39,12 @@ namespace Squidex.Areas.Api.Controllers.Apps.Models
         /// <summary>
         /// The optional label of the app.
         /// </summary>
-        public string Label { get; set; }
+        public string? Label { get; set; }
 
         /// <summary>
         /// The optional description of the app.
         /// </summary>
-        public string Description { get; set; }
+        public string? Description { get; set; }
 
         /// <summary>
         /// The version of the app.
diff --git a/backend/src/Squidex/Areas/Api/Controllers/Apps/Models/ClientDto.cs b/backend/src/Squidex/Areas/Api/Controllers/Apps/Models/ClientDto.cs
index 6781ee20b..d00146290 100644
--- a/backend/src/Squidex/Areas/Api/Controllers/Apps/Models/ClientDto.cs
+++ b/backend/src/Squidex/Areas/Api/Controllers/Apps/Models/ClientDto.cs
@@ -36,7 +36,7 @@ namespace Squidex.Areas.Api.Controllers.Apps.Models
         /// <summary>
         /// The role of the client.
         /// </summary>
-        public string Role { get; set; }
+        public string? Role { get; set; }
 
         public static ClientDto FromClient(string id, AppClient client)
         {
diff --git a/backend/src/Squidex/Areas/Api/Controllers/Apps/Models/ContributorDto.cs b/backend/src/Squidex/Areas/Api/Controllers/Apps/Models/ContributorDto.cs
index cfad52a07..ba66b1efe 100644
--- a/backend/src/Squidex/Areas/Api/Controllers/Apps/Models/ContributorDto.cs
+++ b/backend/src/Squidex/Areas/Api/Controllers/Apps/Models/ContributorDto.cs
@@ -32,7 +32,7 @@ namespace Squidex.Areas.Api.Controllers.Apps.Models
         /// <summary>
         /// The role of the contributor.
         /// </summary>
-        public string Role { get; set; }
+        public string? Role { get; set; }
 
         public static ContributorDto FromIdAndRole(string id, string role)
         {
diff --git a/backend/src/Squidex/Areas/Api/Controllers/Apps/Models/CreateAppDto.cs b/backend/src/Squidex/Areas/Api/Controllers/Apps/Models/CreateAppDto.cs
index 52a769f50..7a849c274 100644
--- a/backend/src/Squidex/Areas/Api/Controllers/Apps/Models/CreateAppDto.cs
+++ b/backend/src/Squidex/Areas/Api/Controllers/Apps/Models/CreateAppDto.cs
@@ -23,7 +23,7 @@ namespace Squidex.Areas.Api.Controllers.Apps.Models
         /// <summary>
         /// Initialize the app with the inbuilt template.
         /// </summary>
-        public string Template { get; set; }
+        public string? Template { get; set; }
 
         public CreateApp ToCommand()
         {
diff --git a/backend/src/Squidex/Areas/Api/Controllers/Apps/Models/PatternDto.cs b/backend/src/Squidex/Areas/Api/Controllers/Apps/Models/PatternDto.cs
index 678bca542..ae3ed6355 100644
--- a/backend/src/Squidex/Areas/Api/Controllers/Apps/Models/PatternDto.cs
+++ b/backend/src/Squidex/Areas/Api/Controllers/Apps/Models/PatternDto.cs
@@ -36,7 +36,7 @@ namespace Squidex.Areas.Api.Controllers.Apps.Models
         /// <summary>
         /// The regex message.
         /// </summary>
-        public string Message { get; set; }
+        public string? Message { get; set; }
 
         public static PatternDto FromPattern(Guid id, AppPattern pattern, ApiController controller, string app)
         {
diff --git a/backend/src/Squidex/Areas/Api/Controllers/Apps/Models/UpdateAppDto.cs b/backend/src/Squidex/Areas/Api/Controllers/Apps/Models/UpdateAppDto.cs
index 7bd05b95a..13a356e80 100644
--- a/backend/src/Squidex/Areas/Api/Controllers/Apps/Models/UpdateAppDto.cs
+++ b/backend/src/Squidex/Areas/Api/Controllers/Apps/Models/UpdateAppDto.cs
@@ -15,12 +15,12 @@ namespace Squidex.Areas.Api.Controllers.Apps.Models
         /// <summary>
         /// The optional label of your app.
         /// </summary>
-        public string Label { get; set; }
+        public string? Label { get; set; }
 
         /// <summary>
         /// The optional description of your app.
         /// </summary>
-        public string Description { get; set; }
+        public string? Description { get; set; }
 
         public UpdateApp ToCommand()
         {
diff --git a/backend/src/Squidex/Areas/Api/Controllers/Apps/Models/UpdateClientDto.cs b/backend/src/Squidex/Areas/Api/Controllers/Apps/Models/UpdateClientDto.cs
index ab4b91eb8..44e949983 100644
--- a/backend/src/Squidex/Areas/Api/Controllers/Apps/Models/UpdateClientDto.cs
+++ b/backend/src/Squidex/Areas/Api/Controllers/Apps/Models/UpdateClientDto.cs
@@ -22,7 +22,7 @@ namespace Squidex.Areas.Api.Controllers.Apps.Models
         /// <summary>
         /// The role of the client.
         /// </summary>
-        public string Role { get; set; }
+        public string? Role { get; set; }
 
         public UpdateClient ToCommand(string clientId)
         {
diff --git a/backend/src/Squidex/Areas/Api/Controllers/Apps/Models/UpdatePatternDto.cs b/backend/src/Squidex/Areas/Api/Controllers/Apps/Models/UpdatePatternDto.cs
index 4c225880f..384c1c909 100644
--- a/backend/src/Squidex/Areas/Api/Controllers/Apps/Models/UpdatePatternDto.cs
+++ b/backend/src/Squidex/Areas/Api/Controllers/Apps/Models/UpdatePatternDto.cs
@@ -29,7 +29,7 @@ namespace Squidex.Areas.Api.Controllers.Apps.Models
         /// <summary>
         /// The regex message.
         /// </summary>
-        public string Message { get; set; }
+        public string? Message { get; set; }
 
         public AddPattern ToAddCommand()
         {
diff --git a/backend/src/Squidex/Areas/Api/Controllers/Apps/Models/UpdateWorkflowDto.cs b/backend/src/Squidex/Areas/Api/Controllers/Apps/Models/UpdateWorkflowDto.cs
index c930cf146..215b858fd 100644
--- a/backend/src/Squidex/Areas/Api/Controllers/Apps/Models/UpdateWorkflowDto.cs
+++ b/backend/src/Squidex/Areas/Api/Controllers/Apps/Models/UpdateWorkflowDto.cs
@@ -19,7 +19,7 @@ namespace Squidex.Areas.Api.Controllers.Apps.Models
         /// <summary>
         /// The name of the workflow.
         /// </summary>
-        public string Name { get; set; }
+        public string? Name { get; set; }
 
         /// <summary>
         /// The workflow steps.
diff --git a/backend/src/Squidex/Areas/Api/Controllers/Apps/Models/WorkflowDto.cs b/backend/src/Squidex/Areas/Api/Controllers/Apps/Models/WorkflowDto.cs
index 56e51c565..299dd37b2 100644
--- a/backend/src/Squidex/Areas/Api/Controllers/Apps/Models/WorkflowDto.cs
+++ b/backend/src/Squidex/Areas/Api/Controllers/Apps/Models/WorkflowDto.cs
@@ -26,7 +26,7 @@ namespace Squidex.Areas.Api.Controllers.Apps.Models
         /// <summary>
         /// The name of the workflow.
         /// </summary>
-        public string Name { get; set; }
+        public string? Name { get; set; }
 
         /// <summary>
         /// The workflow steps.
diff --git a/backend/src/Squidex/Areas/Api/Controllers/Apps/Models/WorkflowStepDto.cs b/backend/src/Squidex/Areas/Api/Controllers/Apps/Models/WorkflowStepDto.cs
index 9ee0ecaf5..aece664c1 100644
--- a/backend/src/Squidex/Areas/Api/Controllers/Apps/Models/WorkflowStepDto.cs
+++ b/backend/src/Squidex/Areas/Api/Controllers/Apps/Models/WorkflowStepDto.cs
@@ -24,7 +24,7 @@ namespace Squidex.Areas.Api.Controllers.Apps.Models
         /// <summary>
         /// The optional color.
         /// </summary>
-        public string Color { get; set; }
+        public string? Color { get; set; }
 
         /// <summary>
         /// Indicates if updates should not be allowed.
diff --git a/backend/src/Squidex/Areas/Api/Controllers/Assets/Models/AnnotateAssetDto.cs b/backend/src/Squidex/Areas/Api/Controllers/Assets/Models/AnnotateAssetDto.cs
index a86ef6c85..2f2cd6b93 100644
--- a/backend/src/Squidex/Areas/Api/Controllers/Assets/Models/AnnotateAssetDto.cs
+++ b/backend/src/Squidex/Areas/Api/Controllers/Assets/Models/AnnotateAssetDto.cs
@@ -17,12 +17,12 @@ namespace Squidex.Areas.Api.Controllers.Assets.Models
         /// <summary>
         /// The new name of the asset.
         /// </summary>
-        public string FileName { get; set; }
+        public string? FileName { get; set; }
 
         /// <summary>
         /// The new slug of the asset.
         /// </summary>
-        public string Slug { get; set; }
+        public string? Slug { get; set; }
 
         /// <summary>
         /// The new asset tags.
diff --git a/backend/src/Squidex/Areas/Api/Controllers/Assets/Models/AssetDto.cs b/backend/src/Squidex/Areas/Api/Controllers/Assets/Models/AssetDto.cs
index 185a2722a..30b5b4f15 100644
--- a/backend/src/Squidex/Areas/Api/Controllers/Assets/Models/AssetDto.cs
+++ b/backend/src/Squidex/Areas/Api/Controllers/Assets/Models/AssetDto.cs
@@ -34,7 +34,7 @@ namespace Squidex.Areas.Api.Controllers.Assets.Models
         /// <summary>
         /// The file hash.
         /// </summary>
-        public string FileHash { get; set; }
+        public string? FileHash { get; set; }
 
         /// <summary>
         /// The slug.
diff --git a/backend/src/Squidex/Areas/Api/Controllers/Rules/Models/RuleDto.cs b/backend/src/Squidex/Areas/Api/Controllers/Rules/Models/RuleDto.cs
index e70a1b718..b280cab79 100644
--- a/backend/src/Squidex/Areas/Api/Controllers/Rules/Models/RuleDto.cs
+++ b/backend/src/Squidex/Areas/Api/Controllers/Rules/Models/RuleDto.cs
@@ -61,7 +61,7 @@ namespace Squidex.Areas.Api.Controllers.Rules.Models
         /// <summary>
         /// Optional rule name.
         /// </summary>
-        public string Name { get; set; }
+        public string? Name { get; set; }
 
         /// <summary>
         /// The trigger properties.
diff --git a/backend/src/Squidex/Areas/Api/Controllers/Rules/Models/RuleElementDto.cs b/backend/src/Squidex/Areas/Api/Controllers/Rules/Models/RuleElementDto.cs
index 2ba8432d5..c146e2afa 100644
--- a/backend/src/Squidex/Areas/Api/Controllers/Rules/Models/RuleElementDto.cs
+++ b/backend/src/Squidex/Areas/Api/Controllers/Rules/Models/RuleElementDto.cs
@@ -29,22 +29,22 @@ namespace Squidex.Areas.Api.Controllers.Rules.Models
         /// <summary>
         /// Optional title.
         /// </summary>
-        public string Title { get; set; }
+        public string? Title { get; set; }
 
         /// <summary>
         /// The color for the icon.
         /// </summary>
-        public string IconColor { get; set; }
+        public string? IconColor { get; set; }
 
         /// <summary>
         /// The image for the icon.
         /// </summary>
-        public string IconImage { get; set; }
+        public string? IconImage { get; set; }
 
         /// <summary>
         /// The optional link to the product that is integrated.
         /// </summary>
-        public string ReadMore { get; set; }
+        public string? ReadMore { get; set; }
 
         /// <summary>
         /// The properties.
diff --git a/backend/src/Squidex/Areas/Api/Controllers/Rules/Models/RuleEventDto.cs b/backend/src/Squidex/Areas/Api/Controllers/Rules/Models/RuleEventDto.cs
index a513495ab..731fddec7 100644
--- a/backend/src/Squidex/Areas/Api/Controllers/Rules/Models/RuleEventDto.cs
+++ b/backend/src/Squidex/Areas/Api/Controllers/Rules/Models/RuleEventDto.cs
@@ -42,7 +42,7 @@ namespace Squidex.Areas.Api.Controllers.Rules.Models
         /// <summary>
         /// The last dump.
         /// </summary>
-        public string LastDump { get; set; }
+        public string? LastDump { get; set; }
 
         /// <summary>
         /// The number of calls.
diff --git a/backend/src/Squidex/Areas/Api/Controllers/Schemas/Models/AddFieldDto.cs b/backend/src/Squidex/Areas/Api/Controllers/Schemas/Models/AddFieldDto.cs
index b2330cfd8..bb8822ff6 100644
--- a/backend/src/Squidex/Areas/Api/Controllers/Schemas/Models/AddFieldDto.cs
+++ b/backend/src/Squidex/Areas/Api/Controllers/Schemas/Models/AddFieldDto.cs
@@ -23,7 +23,7 @@ namespace Squidex.Areas.Api.Controllers.Schemas.Models
         /// <summary>
         /// Determines the optional partitioning of the field.
         /// </summary>
-        public string Partitioning { get; set; }
+        public string? Partitioning { get; set; }
 
         /// <summary>
         /// The field properties.
diff --git a/backend/src/Squidex/Areas/Api/Controllers/Schemas/Models/ChangeCategoryDto.cs b/backend/src/Squidex/Areas/Api/Controllers/Schemas/Models/ChangeCategoryDto.cs
index 29e497ec6..6e3764d19 100644
--- a/backend/src/Squidex/Areas/Api/Controllers/Schemas/Models/ChangeCategoryDto.cs
+++ b/backend/src/Squidex/Areas/Api/Controllers/Schemas/Models/ChangeCategoryDto.cs
@@ -15,7 +15,7 @@ namespace Squidex.Areas.Api.Controllers.Schemas.Models
         /// <summary>
         /// The name of the category.
         /// </summary>
-        public string Name { get; set; }
+        public string? Name { get; set; }
 
         public ChangeCategory ToCommand()
         {
diff --git a/backend/src/Squidex/Areas/Api/Controllers/Schemas/Models/FieldDto.cs b/backend/src/Squidex/Areas/Api/Controllers/Schemas/Models/FieldDto.cs
index b222fc132..6a361104b 100644
--- a/backend/src/Squidex/Areas/Api/Controllers/Schemas/Models/FieldDto.cs
+++ b/backend/src/Squidex/Areas/Api/Controllers/Schemas/Models/FieldDto.cs
@@ -59,7 +59,7 @@ namespace Squidex.Areas.Api.Controllers.Schemas.Models
         /// <summary>
         /// The nested fields.
         /// </summary>
-        public List<NestedFieldDto> Nested { get; set; }
+        public List<NestedFieldDto>? Nested { get; set; }
 
         public static NestedFieldDto FromField(NestedField field)
         {
diff --git a/backend/src/Squidex/Areas/Api/Controllers/Schemas/Models/FieldPropertiesDto.cs b/backend/src/Squidex/Areas/Api/Controllers/Schemas/Models/FieldPropertiesDto.cs
index 0c127730b..17a0a07bf 100644
--- a/backend/src/Squidex/Areas/Api/Controllers/Schemas/Models/FieldPropertiesDto.cs
+++ b/backend/src/Squidex/Areas/Api/Controllers/Schemas/Models/FieldPropertiesDto.cs
@@ -61,6 +61,7 @@ namespace Squidex.Areas.Api.Controllers.Schemas.Models
         /// <summary>
         /// Tags for automation processes.
         /// </summary>
+        [Required]
         public ReadOnlyCollection<string> Tags { get; set; }
 
         public abstract FieldProperties ToProperties();
diff --git a/backend/src/Squidex/Areas/Api/Controllers/Schemas/Models/SchemaPropertiesDto.cs b/backend/src/Squidex/Areas/Api/Controllers/Schemas/Models/SchemaPropertiesDto.cs
index ecff3be2d..e85346a73 100644
--- a/backend/src/Squidex/Areas/Api/Controllers/Schemas/Models/SchemaPropertiesDto.cs
+++ b/backend/src/Squidex/Areas/Api/Controllers/Schemas/Models/SchemaPropertiesDto.cs
@@ -16,17 +16,18 @@ namespace Squidex.Areas.Api.Controllers.Schemas.Models
         /// Optional label for the editor.
         /// </summary>
         [StringLength(100)]
-        public string Label { get; set; }
+        public string? Label { get; set; }
 
         /// <summary>
         /// Hints to describe the schema.
         /// </summary>
         [StringLength(1000)]
-        public string Hints { get; set; }
+        public string? Hints { get; set; }
 
         /// <summary>
         /// Tags for automation processes.
         /// </summary>
+        [Required]
         public ReadOnlyCollection<string> Tags { get; set; }
     }
 }
diff --git a/backend/src/Squidex/Areas/Api/Controllers/Schemas/Models/SchemaScriptsDto.cs b/backend/src/Squidex/Areas/Api/Controllers/Schemas/Models/SchemaScriptsDto.cs
index 3e2fd8a2d..bf00dd8e0 100644
--- a/backend/src/Squidex/Areas/Api/Controllers/Schemas/Models/SchemaScriptsDto.cs
+++ b/backend/src/Squidex/Areas/Api/Controllers/Schemas/Models/SchemaScriptsDto.cs
@@ -16,27 +16,27 @@ namespace Squidex.Areas.Api.Controllers.Schemas.Models
         /// <summary>
         /// The script that is executed for each query when querying contents.
         /// </summary>
-        public string Query { get; set; }
+        public string? Query { get; set; }
 
         /// <summary>
         /// The script that is executed when creating a content.
         /// </summary>
-        public string Create { get; set; }
+        public string? Create { get; set; }
 
         /// <summary>
         /// The script that is executed when updating a content.
         /// </summary>
-        public string Update { get; set; }
+        public string? Update { get; set; }
 
         /// <summary>
         /// The script that is executed when deleting a content.
         /// </summary>
-        public string Delete { get; set; }
+        public string? Delete { get; set; }
 
         /// <summary>
         /// The script that is executed when change a content status.
         /// </summary>
-        public string Change { get; set; }
+        public string? Change { get; set; }
 
         public ConfigureScripts ToCommand()
         {
diff --git a/backend/src/Squidex/Areas/Api/Controllers/Schemas/Models/UpdateSchemaDto.cs b/backend/src/Squidex/Areas/Api/Controllers/Schemas/Models/UpdateSchemaDto.cs
index f2d23b23b..34436fd50 100644
--- a/backend/src/Squidex/Areas/Api/Controllers/Schemas/Models/UpdateSchemaDto.cs
+++ b/backend/src/Squidex/Areas/Api/Controllers/Schemas/Models/UpdateSchemaDto.cs
@@ -19,13 +19,13 @@ namespace Squidex.Areas.Api.Controllers.Schemas.Models
         /// Optional label for the editor.
         /// </summary>
         [StringLength(100)]
-        public string Label { get; set; }
+        public string? Label { get; set; }
 
         /// <summary>
         /// Hints to describe the schema.
         /// </summary>
         [StringLength(1000)]
-        public string Hints { get; set; }
+        public string? Hints { get; set; }
 
         /// <summary>
         /// Tags for automation processes.
diff --git a/backend/src/Squidex/Areas/Api/Controllers/Schemas/Models/UpsertSchemaDto.cs b/backend/src/Squidex/Areas/Api/Controllers/Schemas/Models/UpsertSchemaDto.cs
index be7290131..c53b55793 100644
--- a/backend/src/Squidex/Areas/Api/Controllers/Schemas/Models/UpsertSchemaDto.cs
+++ b/backend/src/Squidex/Areas/Api/Controllers/Schemas/Models/UpsertSchemaDto.cs
@@ -37,7 +37,7 @@ namespace Squidex.Areas.Api.Controllers.Schemas.Models
         /// <summary>
         /// The category.
         /// </summary>
-        public string Category { get; set; }
+        public string? Category { get; set; }
 
         /// <summary>
         /// Set it to true to autopublish the schema.
diff --git a/backend/src/Squidex/Areas/Api/Controllers/Schemas/Models/UpsertSchemaFieldDto.cs b/backend/src/Squidex/Areas/Api/Controllers/Schemas/Models/UpsertSchemaFieldDto.cs
index a42fee220..53b872400 100644
--- a/backend/src/Squidex/Areas/Api/Controllers/Schemas/Models/UpsertSchemaFieldDto.cs
+++ b/backend/src/Squidex/Areas/Api/Controllers/Schemas/Models/UpsertSchemaFieldDto.cs
@@ -37,7 +37,7 @@ namespace Squidex.Areas.Api.Controllers.Schemas.Models
         /// <summary>
         /// Determines the optional partitioning of the field.
         /// </summary>
-        public string Partitioning { get; set; }
+        public string? Partitioning { get; set; }
 
         /// <summary>
         /// The field properties.
@@ -48,6 +48,6 @@ namespace Squidex.Areas.Api.Controllers.Schemas.Models
         /// <summary>
         /// The nested fields.
         /// </summary>
-        public List<UpsertSchemaNestedFieldDto> Nested { get; set; }
+        public List<UpsertSchemaNestedFieldDto>? Nested { get; set; }
     }
 }
\ No newline at end of file