diff --git a/core/playlists_test.go b/core/playlists_test.go
index ab5d76831..8aafabb7f 100644
--- a/core/playlists_test.go
+++ b/core/playlists_test.go
@@ -6,7 +6,6 @@ import (
 
 	"github.com/navidrome/navidrome/model"
 	"github.com/navidrome/navidrome/tests"
-
 	. "github.com/onsi/ginkgo"
 	. "github.com/onsi/gomega"
 )
diff --git a/model/criteria/criteria.go b/model/criteria/criteria.go
index 32f355951..394c5590a 100644
--- a/model/criteria/criteria.go
+++ b/model/criteria/criteria.go
@@ -35,9 +35,9 @@ func (c Criteria) MarshalJSON() ([]byte, error) {
 	aux := struct {
 		All    []Expression `json:"all,omitempty"`
 		Any    []Expression `json:"any,omitempty"`
-		Sort   string       `json:"sort"`
+		Sort   string       `json:"sort,omitempty"`
 		Order  string       `json:"order,omitempty"`
-		Limit  int          `json:"limit"`
+		Limit  int          `json:"limit,omitempty"`
 		Offset int          `json:"offset,omitempty"`
 	}{
 		Sort:   c.Sort,
diff --git a/model/smartplaylist.go b/model/smartplaylist.go
deleted file mode 100644
index 70b6d1ca7..000000000
--- a/model/smartplaylist.go
+++ /dev/null
@@ -1,106 +0,0 @@
-package model
-
-import (
-	"encoding/json"
-	"errors"
-)
-
-type SmartPlaylist struct {
-	RuleGroup
-	Order string `json:"order,omitempty"`
-	Limit int    `json:"limit,omitempty"`
-}
-
-type RuleGroup struct {
-	Combinator string `json:"combinator"`
-	Rules      Rules  `json:"rules"`
-}
-
-type Rules []IRule
-
-type IRule interface {
-	Fields() []string
-}
-
-type Rule struct {
-	Field    string      `json:"field"`
-	Operator string      `json:"operator"`
-	Value    interface{} `json:"value,omitempty"`
-}
-
-func (r Rule) Fields() []string {
-	return []string{r.Field}
-}
-
-func (rg RuleGroup) Fields() []string {
-	var result []string
-	unique := map[string]struct{}{}
-	for _, r := range rg.Rules {
-		for _, f := range r.Fields() {
-			if _, added := unique[f]; !added {
-				result = append(result, f)
-				unique[f] = struct{}{}
-			}
-		}
-	}
-	return result
-}
-
-func (rs *Rules) UnmarshalJSON(data []byte) error {
-	var rawRules []json.RawMessage
-	if err := json.Unmarshal(data, &rawRules); err != nil {
-		return err
-	}
-	rules := make(Rules, len(rawRules))
-	for i, rawRule := range rawRules {
-		var r Rule
-		if err := json.Unmarshal(rawRule, &r); err == nil && r.Field != "" {
-			rules[i] = r
-			continue
-		}
-		var g RuleGroup
-		if err := json.Unmarshal(rawRule, &g); err == nil && g.Combinator != "" {
-			rules[i] = g
-			continue
-		}
-		return errors.New("Invalid json. Neither a Rule nor a RuleGroup: " + string(rawRule))
-	}
-	*rs = rules
-	return nil
-}
-
-var SmartPlaylistFields = []string{
-	"title",
-	"album",
-	"artist",
-	"albumartist",
-	"albumartwork",
-	"tracknumber",
-	"discnumber",
-	"year",
-	"size",
-	"compilation",
-	"dateadded",
-	"datemodified",
-	"discsubtitle",
-	"comment",
-	"lyrics",
-	"sorttitle",
-	"sortalbum",
-	"sortartist",
-	"sortalbumartist",
-	"albumtype",
-	"albumcomment",
-	"catalognumber",
-	"filepath",
-	"filetype",
-	"duration",
-	"bitrate",
-	"bpm",
-	"channels",
-	"genre",
-	"loved",
-	"lastplayed",
-	"playcount",
-	"rating",
-}
diff --git a/model/smartplaylist_test.go b/model/smartplaylist_test.go
deleted file mode 100644
index 2f2e73530..000000000
--- a/model/smartplaylist_test.go
+++ /dev/null
@@ -1,101 +0,0 @@
-package model_test
-
-import (
-	"bytes"
-	"encoding/json"
-
-	"github.com/navidrome/navidrome/model"
-	. "github.com/onsi/ginkgo"
-	. "github.com/onsi/gomega"
-)
-
-var _ = Describe("SmartPlaylist", func() {
-	var goObj model.SmartPlaylist
-	var jsonObj string
-	BeforeEach(func() {
-		goObj = model.SmartPlaylist{
-			RuleGroup: model.RuleGroup{
-				Combinator: "and", Rules: model.Rules{
-					model.Rule{Field: "title", Operator: "contains", Value: "love"},
-					model.Rule{Field: "year", Operator: "is in the range", Value: []int{1980, 1989}},
-					model.Rule{Field: "loved", Operator: "is true"},
-					model.Rule{Field: "lastPlayed", Operator: "in the last", Value: 30},
-					model.RuleGroup{
-						Combinator: "or",
-						Rules: model.Rules{
-							model.Rule{Field: "artist", Operator: "is not", Value: "zé"},
-							model.Rule{Field: "album", Operator: "is", Value: "4"},
-						},
-					},
-				}},
-			Order: "artist asc",
-			Limit: 100,
-		}
-		var b bytes.Buffer
-		err := json.Compact(&b, []byte(`
-{
-  "combinator":"and",
-  "rules":[
-    {
-      "field":"title",
-      "operator":"contains",
-      "value":"love"
-    },
-    {
-      "field":"year",
-      "operator":"is in the range",
-      "value":[
-        1980,
-        1989
-      ]
-    },
-    {
-      "field":"loved",
-      "operator":"is true"
-    },
-    {
-      "field":"lastPlayed",
-      "operator":"in the last",
-      "value":30
-    },
-    {
-      "combinator":"or",
-      "rules":[
-        {
-          "field":"artist",
-          "operator":"is not",
-          "value":"zé"
-        },
-        {
-          "field":"album",
-          "operator":"is",
-          "value":"4"
-        }
-      ]
-    }
-  ],
-  "order":"artist asc",
-  "limit":100
-}`))
-		if err != nil {
-			panic(err)
-		}
-		jsonObj = b.String()
-	})
-	It("finds all fields", func() {
-		Expect(goObj.Fields()).To(ConsistOf("title", "year", "loved", "lastPlayed", "artist", "album"))
-	})
-	It("marshals to JSON", func() {
-		j, err := json.Marshal(goObj)
-		Expect(err).ToNot(HaveOccurred())
-		Expect(string(j)).To(Equal(jsonObj))
-	})
-	It("is reversible to/from JSON", func() {
-		var newObj model.SmartPlaylist
-		err := json.Unmarshal([]byte(jsonObj), &newObj)
-		Expect(err).ToNot(HaveOccurred())
-		j, err := json.Marshal(newObj)
-		Expect(err).ToNot(HaveOccurred())
-		Expect(string(j)).To(Equal(jsonObj))
-	})
-})