diff --git a/compose/service/values/validator.go b/compose/service/values/validator.go
index e6787b307..a6cb15d0b 100644
--- a/compose/service/values/validator.go
+++ b/compose/service/values/validator.go
@@ -96,6 +96,9 @@ func (vldtr *validator) FileRefChecker(fn ReferenceChecker) {
 func (vldtr validator) Run(ctx context.Context, s store.Storer, m *types.Module, r *types.Record) (out *types.RecordValueErrorSet) {
 	var (
 		f *types.ModuleField
+
+		valParser = parser()
+		valDict   = r.Values.Dict(m.Fields)
 	)
 
 	out = &types.RecordValueErrorSet{}
@@ -132,7 +135,7 @@ fields:
 	}
 
 	for _, v := range r.Values {
-		if !v.IsUpdated() || v.IsUpdated() {
+		if !v.IsUpdated() || v.IsDeleted() {
 			// We'll validate only updated (and non-deleted) values
 			continue
 		}
@@ -141,33 +144,67 @@ fields:
 			continue
 		}
 
-		if v.Value == "" {
-			// Nothing to do with empty value
-			return nil
+		if !(f.Expressions.DisableDefaultValidators && len(f.Expressions.Validators) > 0) {
+			if v.Value == "" {
+				// Nothing to do with empty value
+				return nil
+			}
+
+			// Per field type validators
+			switch strings.ToLower(f.Kind) {
+			case "bool":
+				out.Push(vldtr.vBool(v, f, r, m)...)
+			case "datetime":
+				out.Push(vldtr.vDatetime(v, f, r, m)...)
+			case "email":
+				out.Push(vldtr.vEmail(v, f, r, m)...)
+			case "file":
+				out.Push(vldtr.vFile(ctx, s, v, f, r, m)...)
+			case "number":
+				out.Push(vldtr.vNumber(v, f, r, m)...)
+			case "record":
+				out.Push(vldtr.vRecord(ctx, s, v, f, r, m)...)
+			case "select":
+				out.Push(vldtr.vSelect(v, f, r, m)...)
+			//case "string":
+			//	out.Push(vldtr.vString(v, f, r, m)...)
+			case "url":
+				out.Push(vldtr.vUrl(v, f, r, m)...)
+			case "user":
+				out.Push(vldtr.vUser(ctx, s, v, f, r, m)...)
+			}
 		}
 
-		// Per field type validators
-		switch strings.ToLower(f.Kind) {
-		case "bool":
-			out.Push(vldtr.vBool(v, f, r, m)...)
-		case "datetime":
-			out.Push(vldtr.vDatetime(v, f, r, m)...)
-		case "email":
-			out.Push(vldtr.vEmail(v, f, r, m)...)
-		case "file":
-			out.Push(vldtr.vFile(ctx, s, v, f, r, m)...)
-		case "number":
-			out.Push(vldtr.vNumber(v, f, r, m)...)
-		case "record":
-			out.Push(vldtr.vRecord(ctx, s, v, f, r, m)...)
-		case "select":
-			out.Push(vldtr.vSelect(v, f, r, m)...)
-		//case "string":
-		//	out.Push(vldtr.vString(v, f, r, m)...)
-		case "url":
-			out.Push(vldtr.vUrl(v, f, r, m)...)
-		case "user":
-			out.Push(vldtr.vUser(ctx, s, v, f, r, m)...)
+		if len(f.Expressions.Validators) > 0 {
+			for _, cv := range f.Expressions.Validators {
+				eval, err := valParser.NewEvaluable(cv.Test)
+				if err != nil {
+					out.Push(makeInternalErr(f, err))
+					break
+				}
+
+				invalid, err := eval.EvalBool(ctx, map[string]interface{}{
+					"value":    v.Value,
+					"oldValue": v.OldValue,
+					"values":   valDict,
+				})
+
+				if err != nil {
+					out.Push(makeInternalErr(f, err))
+					break
+				}
+
+				if invalid {
+					out.Push(types.RecordValueError{
+						Kind:    "error",
+						Message: cv.Error,
+						Meta:    map[string]interface{}{"field": f.Name}},
+					)
+
+					// break at first failed test
+					break
+				}
+			}
 		}
 	}
 
diff --git a/compose/service/values/validator_test.go b/compose/service/values/validator_test.go
index b3c1bdae0..90becc78d 100644
--- a/compose/service/values/validator_test.go
+++ b/compose/service/values/validator_test.go
@@ -1,7 +1,9 @@
 package values
 
 import (
+	"context"
 	"github.com/cortezaproject/corteza-server/compose/types"
+	"github.com/stretchr/testify/require"
 	"reflect"
 	"testing"
 	"time"
@@ -218,3 +220,25 @@ func Test_validator_vSelect(t *testing.T) {
 		})
 	}
 }
+
+func Test_validator_customExpr(t *testing.T) {
+	var (
+		vldtr = validator{}
+		m     = &types.Module{}
+		f     = &types.ModuleField{Name: "num", Kind: "Number"}
+		r     = &types.Record{}
+	)
+
+	f.Expressions.Validators = []types.ModuleFieldValidator{
+		{Test: "value > 5", Error: "value is lower than 5"},
+	}
+	m.Fields = append(m.Fields, f)
+	r.Values = r.Values.Replace("num", "1")
+
+	rve := vldtr.Run(context.Background(), nil, m, r)
+	require.False(t, rve.IsValid())
+
+	r.Values = r.Values.Replace("num", "10")
+	rve = vldtr.Run(context.Background(), nil, m, r)
+	require.True(t, rve.IsValid())
+}
diff --git a/compose/types/module_field.go b/compose/types/module_field.go
index 76fdd6cc4..316b397dd 100644
--- a/compose/types/module_field.go
+++ b/compose/types/module_field.go
@@ -45,14 +45,18 @@ type (
 	ModuleFieldExpr struct {
 		Value      string   `json:"value,omitempty"`
 		Sanitizers []string `json:"sanitizers,omitempty"`
-		//Validators []struct {
-		//	Test  string `json:"test,omitempty"`
-		//	Error string `json:"error,omitempty"`
-		//} `json:"validators,omitempty"`
+
+		Validators               []ModuleFieldValidator `json:"validators,omitempty"`
+		DisableDefaultValidators bool                   `json:"disableDefaultValidators,omitempty"`
 
 		Formatters               []string `json:"formatters,omitempty"`
 		DisableDefaultFormatters bool     `json:"disableDefaultFormatters,omitempty"`
 	}
+
+	ModuleFieldValidator struct {
+		Test  string `json:"test,omitempty"`
+		Error string `json:"error,omitempty"`
+	}
 )
 
 var (
diff --git a/compose/types/record_value.go b/compose/types/record_value.go
index 90b0011bc..c003e3afc 100644
--- a/compose/types/record_value.go
+++ b/compose/types/record_value.go
@@ -96,9 +96,10 @@ func (set RecordValueSet) Replace(name string, values ...string) (vv RecordValue
 
 	for p, v := range values {
 		vv = append(vv, &RecordValue{
-			Name:  name,
-			Value: v,
-			Place: uint(p),
+			Name:    name,
+			Value:   v,
+			Place:   uint(p),
+			Updated: true,
 		})
 	}