diff --git a/go.mod b/go.mod
index 1f5bcc264..cff93d4c8 100644
--- a/go.mod
+++ b/go.mod
@@ -179,7 +179,7 @@ require (
 	github.com/modern-go/reflect2 v1.0.2 // indirect
 	github.com/muesli/clusters v0.0.0-20200529215643-2700303c1762 // indirect
 	github.com/muesli/kmeans v0.3.1 // indirect
-	github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2 // indirect
+	github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2
 	github.com/prometheus/client_golang v1.19.1
 	github.com/prometheus/client_model v0.6.1 // indirect
 	github.com/prometheus/common v0.54.0 // indirect
diff --git a/internal/api/grpc/admin/import_integration_test.go b/internal/api/grpc/admin/import_integration_test.go
new file mode 100644
index 000000000..1ee7d7d88
--- /dev/null
+++ b/internal/api/grpc/admin/import_integration_test.go
@@ -0,0 +1,492 @@
+//go:build integration
+
+package admin_test
+
+import (
+	"testing"
+	"time"
+
+	"github.com/brianvoe/gofakeit/v6"
+	"github.com/google/uuid"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	"github.com/zitadel/zitadel/internal/integration"
+	"github.com/zitadel/zitadel/pkg/grpc/admin"
+	"github.com/zitadel/zitadel/pkg/grpc/management"
+	v1 "github.com/zitadel/zitadel/pkg/grpc/v1"
+)
+
+func TestServer_ImportData(t *testing.T) {
+	orgIDs := generateIDs(10)
+	projectIDs := generateIDs(10)
+	userIDs := generateIDs(10)
+	grantIDs := generateIDs(10)
+
+	tests := []struct {
+		name    string
+		req     *admin.ImportDataRequest
+		want    *admin.ImportDataResponse
+		wantErr bool
+	}{
+		{
+			name: "success",
+			req: &admin.ImportDataRequest{
+				Data: &admin.ImportDataRequest_DataOrgs{
+					DataOrgs: &admin.ImportDataOrg{
+						Orgs: []*admin.DataOrg{
+							{
+								OrgId: orgIDs[0],
+								Org: &management.AddOrgRequest{
+									Name: gofakeit.ProductName(),
+								},
+								Projects: []*v1.DataProject{
+									{
+										ProjectId: projectIDs[0],
+										Project: &management.AddProjectRequest{
+											Name:                 gofakeit.AppName(),
+											ProjectRoleAssertion: true,
+										},
+									},
+									{
+										ProjectId: projectIDs[1],
+										Project: &management.AddProjectRequest{
+											Name:                 gofakeit.AppName(),
+											ProjectRoleAssertion: false,
+										},
+									},
+								},
+								ProjectRoles: []*management.AddProjectRoleRequest{
+									{
+										ProjectId:   projectIDs[0],
+										RoleKey:     "role1",
+										DisplayName: "role1",
+									},
+									{
+										ProjectId:   projectIDs[0],
+										RoleKey:     "role2",
+										DisplayName: "role2",
+									},
+									{
+										ProjectId:   projectIDs[1],
+										RoleKey:     "role3",
+										DisplayName: "role3",
+									},
+									{
+										ProjectId:   projectIDs[1],
+										RoleKey:     "role4",
+										DisplayName: "role4",
+									},
+								},
+								HumanUsers: []*v1.DataHumanUser{
+									{
+										UserId: userIDs[0],
+										User: &management.ImportHumanUserRequest{
+											UserName: gofakeit.Username(),
+											Profile: &management.ImportHumanUserRequest_Profile{
+												FirstName:         gofakeit.FirstName(),
+												LastName:          gofakeit.LastName(),
+												DisplayName:       gofakeit.Username(),
+												PreferredLanguage: gofakeit.LanguageBCP(),
+											},
+											Email: &management.ImportHumanUserRequest_Email{
+												Email:           gofakeit.Email(),
+												IsEmailVerified: true,
+											},
+										},
+									},
+									{
+										UserId: userIDs[1],
+										User: &management.ImportHumanUserRequest{
+											UserName: gofakeit.Username(),
+											Profile: &management.ImportHumanUserRequest_Profile{
+												FirstName:         gofakeit.FirstName(),
+												LastName:          gofakeit.LastName(),
+												DisplayName:       gofakeit.Username(),
+												PreferredLanguage: gofakeit.LanguageBCP(),
+											},
+											Email: &management.ImportHumanUserRequest_Email{
+												Email:           gofakeit.Email(),
+												IsEmailVerified: true,
+											},
+										},
+									},
+								},
+								ProjectGrants: []*v1.DataProjectGrant{
+									{
+										GrantId: grantIDs[0],
+										ProjectGrant: &management.AddProjectGrantRequest{
+											ProjectId:    projectIDs[0],
+											GrantedOrgId: orgIDs[1],
+											RoleKeys:     []string{"role1", "role2"},
+										},
+									},
+									{
+										GrantId: grantIDs[1],
+										ProjectGrant: &management.AddProjectGrantRequest{
+											ProjectId:    projectIDs[1],
+											GrantedOrgId: orgIDs[1],
+											RoleKeys:     []string{"role3", "role4"},
+										},
+									},
+									{
+										GrantId: grantIDs[2],
+										ProjectGrant: &management.AddProjectGrantRequest{
+											ProjectId:    projectIDs[0],
+											GrantedOrgId: orgIDs[2],
+											RoleKeys:     []string{"role1", "role2"},
+										},
+									},
+									{
+										GrantId: grantIDs[3],
+										ProjectGrant: &management.AddProjectGrantRequest{
+											ProjectId:    projectIDs[1],
+											GrantedOrgId: orgIDs[2],
+											RoleKeys:     []string{"role3", "role4"},
+										},
+									},
+								},
+							},
+							{
+								OrgId: orgIDs[1],
+								Org: &management.AddOrgRequest{
+									Name: gofakeit.ProductName(),
+								},
+								UserGrants: []*management.AddUserGrantRequest{
+									{
+										UserId:         userIDs[0],
+										ProjectId:      projectIDs[0],
+										ProjectGrantId: grantIDs[0],
+									},
+									{
+										UserId:         userIDs[0],
+										ProjectId:      projectIDs[1],
+										ProjectGrantId: grantIDs[1],
+									},
+								},
+							},
+							{
+								OrgId: orgIDs[2],
+								Org: &management.AddOrgRequest{
+									Name: gofakeit.ProductName(),
+								},
+								UserGrants: []*management.AddUserGrantRequest{
+									{
+										UserId:         userIDs[1],
+										ProjectId:      projectIDs[0],
+										ProjectGrantId: grantIDs[2],
+									},
+									{
+										UserId:         userIDs[1],
+										ProjectId:      projectIDs[1],
+										ProjectGrantId: grantIDs[3],
+									},
+								},
+							},
+						},
+					},
+				},
+				Timeout: time.Minute.String(),
+			},
+			want: &admin.ImportDataResponse{
+				Success: &admin.ImportDataSuccess{
+					Orgs: []*admin.ImportDataSuccessOrg{
+						{
+							OrgId:      orgIDs[0],
+							ProjectIds: projectIDs[0:2],
+							ProjectRoles: []string{
+								projectIDs[0] + "_role1",
+								projectIDs[0] + "_role2",
+								projectIDs[1] + "_role3",
+								projectIDs[1] + "_role4",
+							},
+							HumanUserIds: userIDs[0:2],
+							ProjectGrants: []*admin.ImportDataSuccessProjectGrant{
+								{
+									GrantId:   grantIDs[0],
+									ProjectId: projectIDs[0],
+									OrgId:     orgIDs[1],
+								},
+								{
+									GrantId:   grantIDs[1],
+									ProjectId: projectIDs[1],
+									OrgId:     orgIDs[1],
+								},
+								{
+									GrantId:   grantIDs[2],
+									ProjectId: projectIDs[0],
+									OrgId:     orgIDs[2],
+								},
+								{
+									GrantId:   grantIDs[3],
+									ProjectId: projectIDs[1],
+									OrgId:     orgIDs[2],
+								},
+							},
+						},
+						{
+							OrgId: orgIDs[1],
+							UserGrants: []*admin.ImportDataSuccessUserGrant{
+								{
+									ProjectId: projectIDs[0],
+									UserId:    userIDs[0],
+								},
+								{
+									UserId:    userIDs[0],
+									ProjectId: projectIDs[1],
+								},
+							},
+						},
+						{
+							OrgId: orgIDs[2],
+							UserGrants: []*admin.ImportDataSuccessUserGrant{
+								{
+									ProjectId: projectIDs[0],
+									UserId:    userIDs[1],
+								},
+								{
+									UserId:    userIDs[1],
+									ProjectId: projectIDs[1],
+								},
+							},
+						},
+					},
+				},
+			},
+		},
+		{
+			name: "duplicate project grant error",
+			req: &admin.ImportDataRequest{
+				Data: &admin.ImportDataRequest_DataOrgs{
+					DataOrgs: &admin.ImportDataOrg{
+						Orgs: []*admin.DataOrg{
+							{
+								OrgId: orgIDs[3],
+								Org: &management.AddOrgRequest{
+									Name: gofakeit.ProductName(),
+								},
+								Projects: []*v1.DataProject{
+									{
+										ProjectId: projectIDs[2],
+										Project: &management.AddProjectRequest{
+											Name:                 gofakeit.AppName(),
+											ProjectRoleAssertion: true,
+										},
+									},
+									{
+										ProjectId: projectIDs[3],
+										Project: &management.AddProjectRequest{
+											Name:                 gofakeit.AppName(),
+											ProjectRoleAssertion: false,
+										},
+									},
+								},
+								ProjectRoles: []*management.AddProjectRoleRequest{
+									{
+										ProjectId:   projectIDs[2],
+										RoleKey:     "role1",
+										DisplayName: "role1",
+									},
+									{
+										ProjectId:   projectIDs[2],
+										RoleKey:     "role2",
+										DisplayName: "role2",
+									},
+									{
+										ProjectId:   projectIDs[3],
+										RoleKey:     "role3",
+										DisplayName: "role3",
+									},
+									{
+										ProjectId:   projectIDs[3],
+										RoleKey:     "role4",
+										DisplayName: "role4",
+									},
+								},
+								ProjectGrants: []*v1.DataProjectGrant{
+									{
+										GrantId: grantIDs[4],
+										ProjectGrant: &management.AddProjectGrantRequest{
+											ProjectId:    projectIDs[2],
+											GrantedOrgId: orgIDs[4],
+											RoleKeys:     []string{"role1", "role2"},
+										},
+									},
+									{
+										GrantId: grantIDs[4],
+										ProjectGrant: &management.AddProjectGrantRequest{
+											ProjectId:    projectIDs[2],
+											GrantedOrgId: orgIDs[4],
+											RoleKeys:     []string{"role1", "role2"},
+										},
+									},
+								},
+							},
+						},
+					},
+				},
+				Timeout: time.Minute.String(),
+			},
+			want: &admin.ImportDataResponse{
+				Errors: []*admin.ImportDataError{
+					{
+						Type:    "project_grant",
+						Id:      orgIDs[3] + "_" + projectIDs[2] + "_" + orgIDs[4],
+						Message: "ID=V3-DKcYh Message=Errors.Project.Grant.AlreadyExists Parent=(ERROR: duplicate key value violates unique constraint \"unique_constraints_pkey\" (SQLSTATE 23505))",
+					},
+				},
+				Success: &admin.ImportDataSuccess{
+					Orgs: []*admin.ImportDataSuccessOrg{
+						{
+							OrgId:      orgIDs[3],
+							ProjectIds: projectIDs[2:4],
+							ProjectRoles: []string{
+								projectIDs[2] + "_role1",
+								projectIDs[2] + "_role2",
+								projectIDs[3] + "_role3",
+								projectIDs[3] + "_role4",
+							},
+							ProjectGrants: []*admin.ImportDataSuccessProjectGrant{
+								{
+									GrantId:   grantIDs[4],
+									ProjectId: projectIDs[2],
+									OrgId:     orgIDs[4],
+								},
+							},
+						},
+					},
+				},
+			},
+		},
+		{
+			name: "duplicate project grant member error",
+			req: &admin.ImportDataRequest{
+				Data: &admin.ImportDataRequest_DataOrgs{
+					DataOrgs: &admin.ImportDataOrg{
+						Orgs: []*admin.DataOrg{
+							{
+								OrgId: orgIDs[5],
+								Org: &management.AddOrgRequest{
+									Name: gofakeit.ProductName(),
+								},
+								Projects: []*v1.DataProject{
+									{
+										ProjectId: projectIDs[4],
+										Project: &management.AddProjectRequest{
+											Name:                 gofakeit.AppName(),
+											ProjectRoleAssertion: true,
+										},
+									},
+								},
+								ProjectRoles: []*management.AddProjectRoleRequest{
+									{
+										ProjectId:   projectIDs[4],
+										RoleKey:     "role1",
+										DisplayName: "role1",
+									},
+								},
+								HumanUsers: []*v1.DataHumanUser{
+									{
+										UserId: userIDs[2],
+										User: &management.ImportHumanUserRequest{
+											UserName: gofakeit.Username(),
+											Profile: &management.ImportHumanUserRequest_Profile{
+												FirstName:         gofakeit.FirstName(),
+												LastName:          gofakeit.LastName(),
+												DisplayName:       gofakeit.Username(),
+												PreferredLanguage: gofakeit.LanguageBCP(),
+											},
+											Email: &management.ImportHumanUserRequest_Email{
+												Email:           gofakeit.Email(),
+												IsEmailVerified: true,
+											},
+										},
+									},
+								},
+								ProjectGrants: []*v1.DataProjectGrant{
+									{
+										GrantId: grantIDs[5],
+										ProjectGrant: &management.AddProjectGrantRequest{
+											ProjectId:    projectIDs[4],
+											GrantedOrgId: orgIDs[6],
+											RoleKeys:     []string{"role1", "role2"},
+										},
+									},
+								},
+								ProjectGrantMembers: []*management.AddProjectGrantMemberRequest{
+									{
+										ProjectId: projectIDs[4],
+										GrantId:   grantIDs[5],
+										UserId:    userIDs[2],
+										Roles:     []string{"PROJECT_GRANT_OWNER"},
+									},
+									{
+										ProjectId: projectIDs[4],
+										GrantId:   grantIDs[5],
+										UserId:    userIDs[2],
+										Roles:     []string{"PROJECT_GRANT_OWNER"},
+									},
+								},
+							},
+						},
+					},
+				},
+				Timeout: time.Minute.String(),
+			},
+			want: &admin.ImportDataResponse{
+				Errors: []*admin.ImportDataError{
+					{
+						Type:    "project_grant_member",
+						Id:      orgIDs[5] + "_" + projectIDs[4] + "_" + grantIDs[5] + "_" + userIDs[2],
+						Message: "ID=V3-DKcYh Message=Errors.Project.Member.AlreadyExists Parent=(ERROR: duplicate key value violates unique constraint \"unique_constraints_pkey\" (SQLSTATE 23505))",
+					},
+				},
+				Success: &admin.ImportDataSuccess{
+					Orgs: []*admin.ImportDataSuccessOrg{
+						{
+							OrgId:      orgIDs[5],
+							ProjectIds: projectIDs[4:5],
+							ProjectRoles: []string{
+								projectIDs[4] + "_role1",
+							},
+							HumanUserIds: userIDs[2:3],
+							ProjectGrants: []*admin.ImportDataSuccessProjectGrant{
+								{
+									GrantId:   grantIDs[5],
+									ProjectId: projectIDs[4],
+									OrgId:     orgIDs[6],
+								},
+							},
+							ProjectGrantMembers: []*admin.ImportDataSuccessProjectGrantMember{
+								{
+									ProjectId: projectIDs[4],
+									GrantId:   grantIDs[5],
+									UserId:    userIDs[2],
+								},
+							},
+						},
+					},
+				},
+			},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got, err := Client.ImportData(AdminCTX, tt.req)
+			if tt.wantErr {
+				assert.Error(t, err)
+				return
+			}
+			require.NoError(t, err)
+			integration.EqualProto(t, tt.want, got)
+		})
+	}
+}
+
+func generateIDs(n int) []string {
+	ids := make([]string, n)
+	for i := range ids {
+		ids[i] = uuid.NewString()
+	}
+	return ids
+}
diff --git a/internal/command/project_grant.go b/internal/command/project_grant.go
index 6a5ab96fe..d0f2d210f 100644
--- a/internal/command/project_grant.go
+++ b/internal/command/project_grant.go
@@ -17,14 +17,6 @@ func (c *Commands) AddProjectGrantWithID(ctx context.Context, grant *domain.Proj
 	ctx, span := tracing.NewSpan(ctx)
 	defer func() { span.EndWithError(err) }()
 
-	existingMember, err := c.projectGrantWriteModelByID(ctx, grantID, grant.AggregateID, resourceOwner)
-	if err != nil && !zerrors.IsNotFound(err) {
-		return nil, err
-	}
-	if existingMember != nil && existingMember.State != domain.ProjectGrantStateUnspecified {
-		return nil, zerrors.ThrowInvalidArgument(nil, "PROJECT-2b8fs", "Errors.Project.Grant.AlreadyExisting")
-	}
-
 	return c.addProjectGrantWithID(ctx, grant, grantID, resourceOwner)
 }
 
diff --git a/internal/command/project_grant_member.go b/internal/command/project_grant_member.go
index 9208ebf01..f7ea88747 100644
--- a/internal/command/project_grant_member.go
+++ b/internal/command/project_grant_member.go
@@ -26,13 +26,6 @@ func (c *Commands) AddProjectGrantMember(ctx context.Context, member *domain.Pro
 		return nil, err
 	}
 	addedMember := NewProjectGrantMemberWriteModel(member.AggregateID, member.UserID, member.GrantID)
-	err = c.eventstore.FilterToQueryReducer(ctx, addedMember)
-	if err != nil {
-		return nil, err
-	}
-	if addedMember.State == domain.MemberStateActive {
-		return nil, zerrors.ThrowAlreadyExists(nil, "PROJECT-16dVN", "Errors.Project.Member.AlreadyExists")
-	}
 	projectAgg := ProjectAggregateFromWriteModel(&addedMember.WriteModel)
 	pushedEvents, err := c.eventstore.Push(
 		ctx,
diff --git a/internal/command/project_grant_member_test.go b/internal/command/project_grant_member_test.go
index 2c52eace2..5535cc936 100644
--- a/internal/command/project_grant_member_test.go
+++ b/internal/command/project_grant_member_test.go
@@ -104,58 +104,6 @@ func TestCommandSide_AddProjectGrantMember(t *testing.T) {
 				err: zerrors.IsPreconditionFailed,
 			},
 		},
-		{
-			name: "member already exists, precondition error",
-			fields: fields{
-				eventstore: eventstoreExpect(
-					t,
-					expectFilter(
-						eventFromEventPusher(
-							user.NewHumanAddedEvent(context.Background(),
-								&user.NewAggregate("user1", "org1").Aggregate,
-								"username1",
-								"firstname1",
-								"lastname1",
-								"nickname1",
-								"displayname1",
-								language.German,
-								domain.GenderMale,
-								"email1",
-								true,
-							),
-						),
-					),
-					expectFilter(
-						eventFromEventPusher(
-							project.NewProjectGrantMemberAddedEvent(context.Background(),
-								&project.NewAggregate("project1", "org1").Aggregate,
-								"user1",
-								"projectgrant1",
-							),
-						),
-					),
-				),
-				zitadelRoles: []authz.RoleMapping{
-					{
-						Role: "PROJECT_GRANT_OWNER",
-					},
-				},
-			},
-			args: args{
-				ctx: context.Background(),
-				member: &domain.ProjectGrantMember{
-					ObjectRoot: models.ObjectRoot{
-						AggregateID: "project1",
-					},
-					GrantID: "projectgrant1",
-					UserID:  "user1",
-					Roles:   []string{"PROJECT_GRANT_OWNER"},
-				},
-			},
-			res: res{
-				err: zerrors.IsErrorAlreadyExists,
-			},
-		},
 		{
 			name: "member add uniqueconstraint err, already exists",
 			fields: fields{
@@ -177,7 +125,6 @@ func TestCommandSide_AddProjectGrantMember(t *testing.T) {
 							),
 						),
 					),
-					expectFilter(),
 					expectPushFailed(zerrors.ThrowAlreadyExists(nil, "ERROR", "internal"),
 						project.NewProjectGrantMemberAddedEvent(context.Background(),
 							&project.NewAggregate("project1", "").Aggregate,
@@ -229,7 +176,6 @@ func TestCommandSide_AddProjectGrantMember(t *testing.T) {
 							),
 						),
 					),
-					expectFilter(),
 					expectPush(
 						project.NewProjectGrantMemberAddedEvent(context.Background(),
 							&project.NewAggregate("project1", "").Aggregate,
diff --git a/internal/integration/assert.go b/internal/integration/assert.go
index 225b3399b..610c48cf3 100644
--- a/internal/integration/assert.go
+++ b/internal/integration/assert.go
@@ -4,7 +4,10 @@ import (
 	"testing"
 	"time"
 
+	"github.com/pmezard/go-difflib/difflib"
 	"github.com/stretchr/testify/assert"
+	"google.golang.org/protobuf/encoding/protojson"
+	"google.golang.org/protobuf/proto"
 	"google.golang.org/protobuf/types/known/timestamppb"
 
 	object "github.com/zitadel/zitadel/pkg/grpc/object/v2beta"
@@ -71,3 +74,36 @@ func AssertListDetails[D ListDetailsMsg](t testing.TB, expected, actual D) {
 		assert.WithinRange(t, gotCD, wantCD.Add(-time.Minute), wantCD.Add(time.Minute))
 	}
 }
+
+// EqualProto is inspired by [assert.Equal], only that it tests equality of a proto message.
+// A message diff is printed on the error test log if the messages are not equal.
+//
+// As [assert.Equal] is based on reflection, comparing 2 proto messages sometimes fails,
+// due to their internal state.
+// Expected messages are usually with a vanilla state, eg only exported fields contain data.
+// Actual messages obtained from the gRPC client had unexported fields with data.
+// This makes them hard to compare.
+func EqualProto(t testing.TB, expected, actual proto.Message) bool {
+	t.Helper()
+	if proto.Equal(expected, actual) {
+		return true
+	}
+	t.Errorf("Proto messages not equal: %s", diffProto(expected, actual))
+	return false
+}
+
+func diffProto(expected, actual proto.Message) string {
+	diff, err := difflib.GetUnifiedDiffString(difflib.UnifiedDiff{
+		A:        difflib.SplitLines(protojson.Format(expected)),
+		B:        difflib.SplitLines(protojson.Format(actual)),
+		FromFile: "Expected",
+		FromDate: "",
+		ToFile:   "Actual",
+		ToDate:   "",
+		Context:  1,
+	})
+	if err != nil {
+		panic(err)
+	}
+	return "\n\nDiff:\n" + diff
+}