diff --git a/app/main.go b/app/main.go
index 5fb2fe5..7559529 100644
--- a/app/main.go
+++ b/app/main.go
@@ -94,13 +94,19 @@ func main() {
 		errs.ErrInfoWithInfo("Mi mensaje"))
 
 
+	mu := errs.NewErrMulti(
+		errs.ErrCode("UnError"),
+		errs.ErrCode("UnOtro"),
+		me,
+		)
+
 
 	//printCollection(*collr.NewErrorCollection(me).Collect(true,true,true))
 
 
 	jso := fjson.NewJSONFormatter()
 
-	fmt.Print(string(jso.FormatError(me)))
+	fmt.Print(string(jso.FormatError(mu)))
 
 }
 
diff --git a/core/errs/fmtr/fjson/active.go b/core/errs/fmtr/fjson/active.go
index a4ac845..6e2d0fb 100644
--- a/core/errs/fmtr/fjson/active.go
+++ b/core/errs/fmtr/fjson/active.go
@@ -24,6 +24,8 @@
 package fjson
 
 
+
+
 var (
 
 	G = struct {
@@ -31,8 +33,16 @@ var (
 	}{}
 
 	g = struct {
-
-	}{}
+		null 	[]byte
+		zero 	[]byte
+		vfalse	[]byte
+		vtrue 	[]byte
+	}{
+		null  : []byte("null"),
+		zero  : []byte{'0'},
+		vfalse: []byte{'f','a','l','s','e'},
+		vtrue:  []byte{'t','r','u','e'},
+	}
 )
 
 
diff --git a/core/errs/fmtr/fjson/json_builder.go b/core/errs/fmtr/fjson/json_builder.go
index 210256f..0f779ab 100644
--- a/core/errs/fmtr/fjson/json_builder.go
+++ b/core/errs/fmtr/fjson/json_builder.go
@@ -25,8 +25,8 @@ package fjson
 
 import (
 	"bins/bfers"
+	"encoding/json"
 	"errs/fmtr/collr"
-	"fmt"
 	"strconv"
 	"strings"
 	"time"
@@ -64,15 +64,15 @@ func newJsonBuilder (f *JSONFormatter) *jsonBuilder {
 
 func (b *jsonBuilder) format (err error) {
 
-
-	b.write(*collr.NewErrorCollection(err).Collect(true,true,true),"",false)
+	cl := collr.NewErrorCollection(err)
+	cl.Collect(b.f.AddFields(),b.f.AddCauses(),b.f.AddTrace())
+	b.write(cl,"",false)
 
 }
 
 
-func (b *jsonBuilder) write (coll collr.ErrorCollection,indent string, cont bool) {
-	var in string
-
+func (b *jsonBuilder) write (coll *collr.ErrorCollection,indent string, cont bool) {
+	in := ""
 	if b.pretty {
 		in = indent + strings.Repeat(b.indent, 1)
 		if !cont {
@@ -80,115 +80,129 @@ func (b *jsonBuilder) write (coll collr.ErrorCollection,indent string, cont bool
 		}
 	}
 
-
-
 	b.b.WriteByte('{')
 	if b.pretty {
 		b.b.WriteByte('\n')
 	}
-	b.writeField("error",coll.ErrStr,in,true,true)
+	b.writeField("error",coll.ErrStr,in,true,false, false)
 
 
-	types := coll.Types
-	if len(types) == 1  {
-		b.writeField("type",types[0].String(),in,true,false)
-	} else {
-		b.writeObject("types", in, '[',  b.pretty)
-		for i, t := range coll.Types {
-			if b.pretty {
-				b.b.WriteString(in)
-				b.b.WriteString(b.indent)
-			}
-			b.b.WriteByte('"')
-			b.b.WriteString(t.String())
-			b.b.WriteByte('"')
-			if i < len(coll.Types)-1 {
-				b.b.WriteByte(',')
-			}
-			if b.pretty {
-				b.b.WriteByte('\n')
-			}
-		}
+	if b.f.AddTypes() {
+		types := coll.Types
+
+		b.b.WriteByte(',')
 		if b.pretty {
-			b.b.WriteString(in)
-			b.b.Write2Byte(']', ',')
 			b.b.WriteByte('\n')
+		}
+
+		if len(types) == 1 {
+			b.writeField("type", types[0].String(), in, true, false,false)
 		} else {
-			b.b.Write2Byte(']', ',')
+			b.writeOpen("types", in, '[', b.pretty)
+			for i, t := range coll.Types {
+				if b.pretty {
+					b.b.WriteString(in)
+					b.b.WriteString(b.indent)
+				}
+				b.b.WriteByte('"')
+				b.b.WriteString(t.String())
+				b.b.WriteByte('"')
+				if i < len(coll.Types)-1 {
+					b.b.WriteByte(',')
+				}
+				if b.pretty {
+					b.b.WriteByte('\n')
+				}
+			}
+
+			b.writeClose(in, ']')
 		}
 	}
 
 
 	heads := coll.Fields.GetHeads()
 	if len(heads) > 0 {
-		b.writeObject("fields", in, '{', b.pretty)
-		for i, h := range coll.Fields.GetHeads() {
-			if b.pretty {
-				b.b.WriteString(in)
-				b.b.WriteString(b.indent)
-			}
 
-			b.b.WriteByte('"')
-			b.b.WriteString(h.Name)
-			b.b.WriteByte('"')
-			b.b.WriteString(b.sep)
-			b.writeFieldValue(coll.Fields, h)
-			if i < len(heads)-1 {
+		b.b.WriteByte(',')
+		if b.pretty {
+			b.b.WriteByte('\n')
+		}
+
+		coll.Fields.Sort()
+		b.writeOpen("fields", in, '{', b.pretty)
+		var n = 0
+		var fi string
+		if b.pretty {
+			fi = in + b.indent
+		}
+		for _, h := range heads {
+			p := b.b.Len()
+
+			if n > 0 {
 				b.b.WriteByte(',')
+				if b.pretty {
+					b.b.WriteByte('\n')
+				}
 			}
-			if b.pretty {
-				b.b.WriteByte('\n')
+
+			b.writeFieldName(h.Name,fi)
+
+			if !b.writeFieldValue(coll.Fields, h) {
+				b.b.Truncate(p)
+				continue
 			}
+			n++
 		}
-		if b.pretty {
-			b.b.WriteString(in)
-			b.b.Write2Byte('}', ',')
+		if n > 0 && b.pretty {
 			b.b.WriteByte('\n')
-		} else {
-			b.b.Write2Byte('}', ',')
 		}
-
+		b.writeClose(in,'}')
 	}
 
 	causes := coll.Causes
-	if len(causes) == 1 {
-		b.writeObject("cause",in,0,false)
-		b.write(causes[0],strings.Repeat(b.indent,1),true)
-	} else if len(causes) > 1  {
-		b.writeObject("causes", in, '[', b.pretty)
-		var ci string
+	if len (causes) > 0 {
+
+		b.b.WriteByte(',')
 		if b.pretty {
-			ci = strings.Repeat(b.indent,2)
+			b.b.WriteByte('\n')
 		}
-		for _,ce := range causes {
-			b.write(ce,ci,false)
+
+		if len(causes) == 1 {
+			b.writeOpen("cause", in, 0, false)
+			b.write(&causes[0], strings.Repeat(b.indent, 1), true)
+		} else if len(causes) > 1 {
+			b.writeOpen("causes", in, '[', b.pretty)
+			var ci string
+			if b.pretty {
+				ci = strings.Repeat(b.indent, 2)
+			}
+			for i, ce := range causes {
+				if i > 0 {
+					b.b.WriteByte(',')
+					if b.pretty {
+						b.b.WriteByte('\n')
+					}
+				}
+				b.write(&ce, ci, false)
+			}
+			if b.pretty {
+				b.b.WriteByte('\n')
+			}
+			b.writeClose(in, ']')
 		}
-		b.b.WriteString(in)
-		b.b.WriteByte(']')
-		b.b.WriteByte('\n')
 	}
 
-	b.writeEndObject(indent,'}')
-
 	if b.pretty {
-		b.b.WriteString(indent)
-		b.b.WriteByte('}')
 		b.b.WriteByte('\n')
-	} else {
-		b.b.WriteByte('}')
 	}
+	b.writeClose(indent,'}')
+
 }
 
 
 
-func (b *jsonBuilder) writeObject(name,  indent string, object byte,nl bool) {
-	if b.pretty {
-		b.b.WriteString(indent)
-	}
-	b.b.WriteByte('"')
-	b.b.WriteString(name)
-	b.b.WriteByte('"')
-	b.b.WriteString(b.sep)
+func (b *jsonBuilder) writeOpen(name, indent string, object byte,nl bool) {
+	b.writeFieldName(name,indent)
 	if object != 0 {
 		b.b.WriteByte(object)
 	}
@@ -197,23 +211,29 @@ func (b *jsonBuilder) writeObject(name,  indent string, object byte,nl bool) {
 	}
 }
 
-func (b *jsonBuilder) writeEndObject (indent string, object byte) {
+
+
+func (b *jsonBuilder) writeClose(indent string, object byte) {
 	if b.pretty {
 		b.b.WriteString(indent)
 		b.b.WriteByte(object)
-		b.b.WriteByte('\n')
 	} else {
 		b.b.WriteByte(object)
 	}
 }
 
-
-func (b *jsonBuilder) writeField (name, value, indent string, quote, coma bool) {
-	b.b.WriteString(indent)
+func (b *jsonBuilder) writeFieldName (name, indent string) {
+	if b.pretty {
+		b.b.WriteString(indent)
+	}
 	b.b.WriteByte('"')
 	b.b.WriteString(name)
 	b.b.WriteByte('"')
 	b.b.WriteString(b.sep)
+}
+
+func (b *jsonBuilder) writeField (name, value, indent string, quote, coma, nl bool) {
+	b.writeFieldName(name,indent)
 	if quote {
 		b.b.WriteByte('"')
 	}
@@ -224,34 +244,93 @@ func (b *jsonBuilder) writeField (name, value, indent string, quote, coma bool)
 	if coma {
 		b.b.WriteByte(',')
 	}
-	if b.pretty {
+	if b.pretty && nl {
 		b.b.WriteByte('\n')
 	}
 }
 
 
-func (b *jsonBuilder) writeFieldValue (fields collr.Fields, field *collr.FieldHead) {
+func (b *jsonBuilder) writeFieldValue (fields collr.Fields, field *collr.FieldHead) bool {
 	var v []byte
 	q := true
+
 	switch field.Kind {
-	case collr.FieldKindFloat : v = strconv.AppendFloat(v,fields.GetFieldValueFloat(field),'E',-1,64)
+	case collr.FieldKindFloat :
+		n := fields.GetFieldValueFloat(field)
+		if n == 0 {
+			if b.f.IgnoreDefaults() {
+				return false
+			}
+			v = g.zero
+		} else {
+			v = strconv.AppendFloat(v, n, 'E', -1, 64)
+		}
+
 	case collr.FieldKindInt   :
-		v = strconv.AppendInt(v,int64(fields.GetFieldValueInt(field)),10)
-		q = false
-	case collr.FieldKindString: v = []byte(fields.GetFieldValueString(field))
-	case collr.FieldKindTime  : v = fields.GetFieldValueDate(field).AppendFormat(v,time.RFC822Z)
-	case collr.FieldKindDate  : v = fields.GetFieldValueDate(field).AppendFormat(v,time.RFC822Z)
+		n := fields.GetFieldValueInt(field)
+		if n == 0  {
+			if b.f.IgnoreDefaults() {
+				return false
+			}
+			v = g.zero
+		} else {
+			v = strconv.AppendInt(v, int64(n), 10)
+		}
+		q = b.f.UseQuote()
+
+	case collr.FieldKindString:
+		s := fields.GetFieldValueString(field)
+		if len(s) == 0 && b.f.IgnoreDefaults() {
+			return false
+		}
+		v = []byte(s)
+
+	case collr.FieldKindTime  :
+		d := fields.GetFieldValueDate(field)
+		if d.IsZero()  && b.f.IgnoreDefaults(){
+			return false
+		}
+		v = d.AppendFormat(v,time.RFC822Z)
+
+	case collr.FieldKindDate  :
+		d := fields.GetFieldValueDate(field)
+		if d.IsZero() && b.f.IgnoreDefaults() {
+			return false
+		}
+		v = d.AppendFormat(v,time.RFC822Z)
+
 	case collr.FieldKindBool  :
-		v = strconv.AppendBool(v,fields.GetFieldValueBool(field))
-		q = false
+		t := fields.GetFieldValueBool(field)
+		if !t {
+			if b.f.IgnoreDefaults() {
+				return false
+			}
+			v = g.vfalse
+		} else {
+			v = g.vtrue
+		}
+		q = b.f.UseQuote()
+
 	default:
-		v = []byte(fmt.Sprintf("%v",fields.GetFieldValueAny(field)))
+		a := fields.GetFieldValueAny(field)
+		if a == nil {
+			if b.f.IgnoreDefaults() {
+				return false
+			}
+			v = g.null
+		} else {
+			var e error
+			if v,e = json.Marshal(a); e != nil {
+				return false
+			}
+		}
 	}
 	if q {
 		b.b.WriteByte('"')
 	}
-	b.b.Write(v)
+	_,_ = b.b.Write(v)
 	if q {
 		b.b.WriteByte('"')
 	}
+	return true
 }
diff --git a/core/errs/fmtr/fjson/json_formatter.go b/core/errs/fmtr/fjson/json_formatter.go
index edc344c..59001ca 100644
--- a/core/errs/fmtr/fjson/json_formatter.go
+++ b/core/errs/fmtr/fjson/json_formatter.go
@@ -38,7 +38,7 @@ type (
 
 func NewJSONFormatter (options ...JSONFormatterFnc) *JSONFormatter {
 	f := &JSONFormatter{
-		Option: ShowPretty |UseSpace,
+		Option: ShowPretty |UseSpace | AddTypes |AddFields | AddCauses | AddTrace | IgnoreDefaults,
 		indent: "  ",
 	}
 	for _,o := range options {
diff --git a/core/errs/fmtr/fjson/option.go b/core/errs/fmtr/fjson/option.go
index c66f0d8..f4395af 100644
--- a/core/errs/fmtr/fjson/option.go
+++ b/core/errs/fmtr/fjson/option.go
@@ -28,20 +28,47 @@ package fjson
 
 const (
 
-	ShowPretty 	Option = 1 + iota
+	AddTypes Option = 1 << iota
+	AddFields
+	AddCauses
+	AddTrace
+	ShowPretty
 	UseSpace
-	UseNumQuoted
+	UseQuote
+	IgnoreDefaults
+	SortFields
 )
 
 
 type (
 
-	Option 	uint8
+	Option 	uint16
 )
 
+func (o Option) AddTypes () bool {
+	return o&AddTypes != 0 }
+
+func (o Option) AddFields () bool {
+	return o&AddFields != 0 }
+
+func (o Option) AddCauses () bool {
+	return o&AddCauses != 0 }
+
+func (o Option) AddTrace  () bool {
+	return o&AddTrace != 0 }
 
 func (o Option) ShowPretty () bool {
 	return o&ShowPretty != 0 }
 
 func (o Option) UseSpace () bool {
-	return o&UseSpace != 0 }
\ No newline at end of file
+	return o&UseSpace != 0 }
+
+func (o Option) UseQuote () bool {
+	return o&UseQuote != 0 }
+
+func (o Option) SortFields () bool {
+	return o&SortFields != 0 }
+
+func (o Option) IgnoreDefaults() bool {
+	return o&IgnoreDefaults != 0 }
+