diff --git a/api/feature.go b/api/feature.go
index 6a4dce4..c862659 100644
--- a/api/feature.go
+++ b/api/feature.go
@@ -9,7 +9,7 @@ import (
 	"github.com/Unleash/unleash-go-sdk/v5/internal/strategies"
 )
 
-type ParameterMap map[string]interface{}
+type ParameterMap map[string]any
 
 type FeatureResponse struct {
 	Response
@@ -67,8 +67,8 @@ type Dependency struct {
 	Enabled *bool `json:"enabled"`
 }
 
-func (fr FeatureResponse) FeatureMap() map[string]interface{} {
-	features := map[string]interface{}{}
+func (fr FeatureResponse) FeatureMap() map[string]any {
+	features := map[string]any{}
 	for _, f := range fr.Features {
 		features[f.Name] = f
 	}
diff --git a/api/variant.go b/api/variant.go
index 7bfefd0..bf03aa4 100644
--- a/api/variant.go
+++ b/api/variant.go
@@ -1,5 +1,7 @@
 package api
 
+import "slices"
+
 import "github.com/Unleash/unleash-go-sdk/v5/context"
 
 var DISABLED_VARIANT = &Variant{
@@ -81,12 +83,7 @@ func (o Override) matchValue(ctx *context.Context) bool {
 	if len(o.Values) == 0 {
 		return false
 	}
-	for _, value := range o.Values {
-		if value == o.getIdentifier(ctx) {
-			return true
-		}
-	}
-	return false
+	return slices.Contains(o.Values, o.getIdentifier(ctx))
 }
 
 // Get default variant if feature is not found or if the feature is disabled.
diff --git a/benchmark_test.go b/benchmark_test.go
index c597d56..56b7848 100644
--- a/benchmark_test.go
+++ b/benchmark_test.go
@@ -7,25 +7,66 @@ import (
 	"time"
 
 	"github.com/Unleash/unleash-go-sdk/v5"
+	"github.com/Unleash/unleash-go-sdk/v5/api"
 )
 
+type mockStorage map[string]api.Feature
+
+func (m mockStorage) Get(in string) (any, bool) {
+	out, found := m[in]
+	return out, found
+}
+
+func (m mockStorage) List() []any {
+	res := make([]any, 0, len(m))
+	for _, feature := range m {
+		res = append(res, feature)
+	}
+	return res
+
+}
+
+func (m mockStorage) Init(backupPath string, appName string)        {}
+func (m mockStorage) Load() error                                   { return nil }
+func (m mockStorage) Persist() error                                { return nil }
+func (m mockStorage) Reset(data map[string]any, persist bool) error { return nil }
+
+func ptr[T any](v T) *T {
+	return &v
+}
+
 func BenchmarkFeatureToggleEvaluation(b *testing.B) {
-	unleash.Initialize(
+	err := unleash.Initialize(
 		unleash.WithListener(&unleash.NoopListener{}),
 		unleash.WithAppName("go-benchmark"),
 		unleash.WithUrl("https://app.unleash-hosted.com/demo/api/"),
 		unleash.WithCustomHeaders(http.Header{"Authorization": {"Go-Benchmark:development.be6b5d318c8e77469efb58590022bb6416100261accf95a15046c04d"}}),
+		unleash.WithStorage(mockStorage{
+			"foo": api.Feature{
+				Name:    "foo",
+				Enabled: true,
+				Dependencies: &[]api.Dependency{
+					{Feature: "bar", Enabled: ptr(true)},
+				},
+			},
+			"bar": api.Feature{
+				Name:    "bar",
+				Enabled: true,
+			},
+		}),
 	)
+	if err != nil {
+		b.Fatal(err)
+	}
 
-	b.ResetTimer()
 	startTime := time.Now()
+	b.ReportAllocs()
 
 	for i := 0; i < b.N; i++ {
-		_ = unleash.IsEnabled("go-benchmark")
+		_ = unleash.IsEnabled("foo")
 	}
 
 	endTime := time.Now()
-	b.StopTimer()
 
 	// Calculate ns/op (nanoseconds per operation)
 	nsPerOp := float64(endTime.Sub(startTime).Nanoseconds()) / float64(b.N)
diff --git a/bootstrap_storage.go b/bootstrap_storage.go
index a326d24..aa2765d 100644
--- a/bootstrap_storage.go
+++ b/bootstrap_storage.go
@@ -38,7 +38,7 @@ func (bs *BootstrapStorage) Init(backupPath string, appName string) {
 	}
 }
 
-func (bs *BootstrapStorage) Reset(data map[string]interface{}, persist bool) error {
+func (bs *BootstrapStorage) Reset(data map[string]any, persist bool) error {
 	return bs.backingStore.Reset(data, persist)
 }
 
@@ -46,10 +46,10 @@ func (bs *BootstrapStorage) Persist() error {
 	return bs.backingStore.Persist()
 }
 
-func (bs *BootstrapStorage) Get(key string) (interface{}, bool) {
+func (bs *BootstrapStorage) Get(key string) (any, bool) {
 	return bs.backingStore.Get(key)
 }
 
-func (bs *BootstrapStorage) List() []interface{} {
+func (bs *BootstrapStorage) List() []any {
 	return bs.backingStore.List()
 }
diff --git a/client.go b/client.go
index c8d71b8..d8f90ae 100644
--- a/client.go
+++ b/client.go
@@ -2,6 +2,7 @@ package unleash
 
 import (
 	"fmt"
+	"slices"
 
 	"net/http"
 	"net/url"
@@ -368,14 +369,14 @@ func (uc *Client) isEnabled(feature string, options ...FeatureOption) (api.Strat
 			}, f
 		}
 
-		allConstraints := make([]api.Constraint, 0)
+		allConstraints := make([]api.Constraint, 0, len(segmentConstraints)+len(s.Constraints))
 		allConstraints = append(allConstraints, segmentConstraints...)
 		allConstraints = append(allConstraints, s.Constraints...)
 
 		if ok, err := constraints.Check(ctx, allConstraints); err != nil {
 			uc.errors <- err
 		} else if ok && foundStrategy.IsEnabled(s.Parameters, ctx) {
-			if s.Variants != nil && len(s.Variants) > 0 {
+			if len(s.Variants) > 0 {
 				groupIdValue := s.Parameters[strategy.ParamGroupId]
 				groupId, ok := groupIdValue.(string)
 				if !ok {
@@ -423,7 +424,7 @@ func (uc *Client) isParentDependencySatisfied(feature *api.Feature, context cont
 		// According to the schema, if the enabled property is absent we assume it's true.
 		if parent.Enabled == nil || *parent.Enabled {
 			if parent.Variants != nil && len(*parent.Variants) > 0 && enabledResult.Variant != nil {
-				return enabledResult.Enabled && contains(*parent.Variants, enabledResult.Variant.Name)
+				return enabledResult.Enabled && slices.Contains(*parent.Variants, enabledResult.Variant.Name)
 			}
 			return enabledResult.Enabled
 		}
@@ -431,8 +432,8 @@ func (uc *Client) isParentDependencySatisfied(feature *api.Feature, context cont
 		return !enabledResult.Enabled
 	}
 
-	allDependenciesSatisfied := every(*feature.Dependencies, func(parent interface{}) bool {
-		return dependenciesSatisfied(parent.(api.Dependency))
+	allDependenciesSatisfied := every(*feature.Dependencies, func(parent api.Dependency) bool {
+		return dependenciesSatisfied(parent)
 	})
 
 	return allDependenciesSatisfied
diff --git a/client_test.go b/client_test.go
index 0da683d..a2906a1 100644
--- a/client_test.go
+++ b/client_test.go
@@ -172,12 +172,12 @@ func TestClient_ListFeatures(t *testing.T) {
 							Values:      []string{"constraint-value-1", "constraint-value-2"},
 						},
 					},
-					Parameters: map[string]interface{}{
+					Parameters: map[string]any{
 						"strategy-param-1": "strategy-value-1",
 					},
 				},
 			},
-			Parameters: map[string]interface{}{
+			Parameters: map[string]any{
 				"feature-param-1": "feature-value-1",
 			},
 		},
@@ -302,12 +302,12 @@ func TestClientWithVariantContext(t *testing.T) {
 							Values:      []string{"custom-ctx"},
 						},
 					},
-					Parameters: map[string]interface{}{
+					Parameters: map[string]any{
 						"strategy-param-1": "strategy-value-1",
 					},
 				},
 			},
-			Parameters: map[string]interface{}{
+			Parameters: map[string]any{
 				"feature-param-1": "feature-value-1",
 			},
 			Variants: []api.VariantInternal{
@@ -397,11 +397,11 @@ func TestClient_WithSegment(t *testing.T) {
 					Id:          1,
 					Name:        "default",
 					Constraints: []api.Constraint{},
-					Parameters:  map[string]interface{}{},
+					Parameters:  map[string]any{},
 					Segments:    []int{1},
 				},
 			},
-			Parameters: map[string]interface{}{
+			Parameters: map[string]any{
 				"feature-param-1": "feature-value-1",
 			},
 		},
@@ -482,11 +482,11 @@ func TestClient_WithNonExistingSegment(t *testing.T) {
 					Id:          1,
 					Name:        "default",
 					Constraints: []api.Constraint{},
-					Parameters:  map[string]interface{}{},
+					Parameters:  map[string]any{},
 					Segments:    []int{1},
 				},
 			},
-			Parameters: map[string]interface{}{
+			Parameters: map[string]any{
 				"feature-param-1": "feature-value-1",
 			},
 		},
@@ -561,11 +561,11 @@ func TestClient_WithMultipleSegments(t *testing.T) {
 					Id:          1,
 					Name:        "default",
 					Constraints: []api.Constraint{},
-					Parameters:  map[string]interface{}{},
+					Parameters:  map[string]any{},
 					Segments:    []int{1, 4, 6, 2},
 				},
 			},
-			Parameters: map[string]interface{}{
+			Parameters: map[string]any{
 				"feature-param-1": "feature-value-1",
 			},
 		},
@@ -664,11 +664,11 @@ func TestClient_VariantShouldRespectConstraint(t *testing.T) {
 					Id:          1,
 					Name:        "default",
 					Constraints: []api.Constraint{},
-					Parameters:  map[string]interface{}{},
+					Parameters:  map[string]any{},
 					Segments:    []int{1, 4, 6, 2},
 				},
 			},
-			Parameters: map[string]interface{}{
+			Parameters: map[string]any{
 				"feature-param-1": "feature-value-1",
 			},
 			Variants: []api.VariantInternal{
@@ -783,11 +783,11 @@ func TestClient_VariantShouldFailWhenSegmentConstraintsDontMatch(t *testing.T) {
 					Id:          1,
 					Name:        "default",
 					Constraints: []api.Constraint{},
-					Parameters:  map[string]interface{}{},
+					Parameters:  map[string]any{},
 					Segments:    []int{1, 4, 6, 2},
 				},
 			},
-			Parameters: map[string]interface{}{
+			Parameters: map[string]any{
 				"feature-param-1": "feature-value-1",
 			},
 			Variants: []api.VariantInternal{
@@ -899,7 +899,7 @@ func TestClient_ShouldFavorStrategyVariantOverFeatureVariant(t *testing.T) {
 					Id:          1,
 					Name:        "default",
 					Constraints: []api.Constraint{},
-					Parameters: map[string]interface{}{
+					Parameters: map[string]any{
 						"groupId": "strategyVariantName",
 					},
 					Variants: []api.VariantInternal{
@@ -988,7 +988,7 @@ func TestClient_ShouldReturnOldVariantForNonMatchingStrategyVariant(t *testing.T
 					Id:          1,
 					Name:        "flexibleRollout",
 					Constraints: []api.Constraint{},
-					Parameters: map[string]interface{}{
+					Parameters: map[string]any{
 						"rollout":    0,
 						"stickiness": "default",
 					},
@@ -1010,7 +1010,7 @@ func TestClient_ShouldReturnOldVariantForNonMatchingStrategyVariant(t *testing.T
 					Id:          2,
 					Name:        "flexibleRollout",
 					Constraints: []api.Constraint{},
-					Parameters: map[string]interface{}{
+					Parameters: map[string]any{
 						"rollout":    100,
 						"stickiness": "default",
 					},
diff --git a/config.go b/config.go
index 79700d2..33f7fce 100644
--- a/config.go
+++ b/config.go
@@ -21,7 +21,7 @@ type configOption struct {
 	disableMetrics   bool
 	backupPath       string
 	strategies       []strategy.Strategy
-	listener         interface{}
+	listener         any
 	storage          Storage
 	httpClient       *http.Client
 	customHeaders    http.Header
@@ -35,7 +35,7 @@ type ConfigOption func(*configOption)
 // the listener interfaces. If no listener is registered then the user is responsible
 // for draining the various channels on the client. Failure to do so will stop the client
 // from working as the worker routines will be blocked.
-func WithListener(listener interface{}) ConfigOption {
+func WithListener(listener any) ConfigOption {
 	return func(o *configOption) {
 		o.listener = listener
 	}
@@ -266,7 +266,7 @@ type repositoryOptions struct {
 	backupPath      string
 	refreshInterval time.Duration
 	storage         Storage
-	httpClient     	*http.Client
+	httpClient      *http.Client
 	headers         http.Header
 	isStreaming     bool
 }
@@ -281,5 +281,4 @@ type metricsOptions struct {
 	disableMetrics  bool
 	httpClient      *http.Client
 	headers         http.Header
-	started         *time.Time
 }
diff --git a/example_custom_strategy_test.go b/example_custom_strategy_test.go
index 6b5869d..a1d83f1 100644
--- a/example_custom_strategy_test.go
+++ b/example_custom_strategy_test.go
@@ -2,6 +2,7 @@ package unleash_test
 
 import (
 	"fmt"
+	"slices"
 	"strings"
 	"time"
 
@@ -15,7 +16,7 @@ func (s ActiveForUserWithEmailStrategy) Name() string {
 	return "ActiveForUserWithEmail"
 }
 
-func (s ActiveForUserWithEmailStrategy) IsEnabled(params map[string]interface{}, ctx *context.Context) bool {
+func (s ActiveForUserWithEmailStrategy) IsEnabled(params map[string]any, ctx *context.Context) bool {
 
 	if ctx == nil {
 		return false
@@ -30,13 +31,7 @@ func (s ActiveForUserWithEmailStrategy) IsEnabled(params map[string]interface{},
 		return false
 	}
 
-	for _, e := range strings.Split(emails, ",") {
-		if e == ctx.Properties["emails"] {
-			return true
-		}
-	}
-
-	return false
+	return slices.Contains(strings.Split(emails, ","), ctx.Properties["emails"])
 }
 
 // ExampleCustomStrategy demonstrates using a custom strategy.
diff --git a/impression_test.go b/impression_test.go
index 5a5ba5e..930a94b 100644
--- a/impression_test.go
+++ b/impression_test.go
@@ -45,7 +45,7 @@ func TestImpression_Off(t *testing.T) {
 						{
 							Id:   1,
 							Name: "flexibleRollout",
-							Parameters: map[string]interface{}{
+							Parameters: map[string]any{
 								"rollout":    100,
 								"stickiness": "default",
 							},
@@ -94,7 +94,7 @@ func TestImpression_IsEnabled(t *testing.T) {
 						{
 							Id:   1,
 							Name: "flexibleRollout",
-							Parameters: map[string]interface{}{
+							Parameters: map[string]any{
 								"rollout":    100,
 								"stickiness": "default",
 							},
@@ -152,7 +152,7 @@ func TestImpression_GetVariant(t *testing.T) {
 						{
 							Id:   1,
 							Name: "flexibleRollout",
-							Parameters: map[string]interface{}{
+							Parameters: map[string]any{
 								"rollout":    100,
 								"stickiness": "default",
 								"groupId":    variant,
@@ -227,7 +227,7 @@ func TestImpression_WithContext(t *testing.T) {
 						{
 							Id:   1,
 							Name: "flexibleRollout",
-							Parameters: map[string]interface{}{
+							Parameters: map[string]any{
 								"rollout":    100,
 								"stickiness": "default",
 							},
@@ -307,7 +307,7 @@ func TestImpression_WithContextAndMultipleEvents(t *testing.T) {
 						{
 							Id:   1,
 							Name: "flexibleRollout",
-							Parameters: map[string]interface{}{
+							Parameters: map[string]any{
 								"rollout":    100,
 								"stickiness": "default",
 							},
@@ -398,7 +398,7 @@ func TestImpression_GetChannelMethod(t *testing.T) {
 						{
 							Id:   1,
 							Name: "flexibleRollout",
-							Parameters: map[string]interface{}{
+							Parameters: map[string]any{
 								"rollout":    100,
 								"stickiness": "default",
 							},
diff --git a/internal/constraints/operator_in.go b/internal/constraints/operator_in.go
index 10c1135..1b2c720 100644
--- a/internal/constraints/operator_in.go
+++ b/internal/constraints/operator_in.go
@@ -3,6 +3,7 @@ package constraints
 import (
 	"github.com/Unleash/unleash-go-sdk/v5/api"
 	"github.com/Unleash/unleash-go-sdk/v5/context"
+	"slices"
 )
 
 func operatorNotIn(ctx *context.Context, constraint api.Constraint) bool {
@@ -12,11 +13,5 @@ func operatorNotIn(ctx *context.Context, constraint api.Constraint) bool {
 func operatorIn(ctx *context.Context, constraint api.Constraint) bool {
 	contextValue := ctx.Field(constraint.ContextName)
 
-	for _, constraint := range constraint.Values {
-		if contextValue == constraint {
-			return true
-		}
-	}
-
-	return false
+	return slices.Contains(constraint.Values, contextValue)
 }
diff --git a/internal/strategies/application_hostname.go b/internal/strategies/application_hostname.go
index 6dd0c13..6ce2b87 100644
--- a/internal/strategies/application_hostname.go
+++ b/internal/strategies/application_hostname.go
@@ -22,7 +22,7 @@ func (s applicationHostnameStrategy) Name() string {
 	return "applicationHostname"
 }
 
-func (s applicationHostnameStrategy) IsEnabled(params map[string]interface{}, _ *context.Context) bool {
+func (s applicationHostnameStrategy) IsEnabled(params map[string]any, _ *context.Context) bool {
 	value, found := params[strategy.ParamHostNames]
 	if !found {
 		return false
diff --git a/internal/strategies/application_hostname_test.go b/internal/strategies/application_hostname_test.go
index 063c42e..e6d0586 100644
--- a/internal/strategies/application_hostname_test.go
+++ b/internal/strategies/application_hostname_test.go
@@ -30,7 +30,7 @@ func TestApplicationHostnameStrategy_IsEnabled(t *testing.T) {
 
 	t.Run("h=os.hostname", func(t *testing.T) {
 		hostname, _ := resolveHostname()
-		isEnabled := s.IsEnabled(map[string]interface{}{
+		isEnabled := s.IsEnabled(map[string]any{
 			strategy.ParamHostNames: hostname,
 		}, nil)
 
@@ -39,7 +39,7 @@ func TestApplicationHostnameStrategy_IsEnabled(t *testing.T) {
 
 	t.Run("h=list(os.hostname)", func(t *testing.T) {
 		hostname, _ := resolveHostname()
-		isEnabled := s.IsEnabled(map[string]interface{}{
+		isEnabled := s.IsEnabled(map[string]any{
 			strategy.ParamHostNames: "localhost," + hostname,
 		}, nil)
 
@@ -52,7 +52,7 @@ func TestApplicationHostnameStrategy_IsEnabled(t *testing.T) {
 		// needed to re-read env-var
 		s = NewApplicationHostnameStrategy()
 
-		isEnabled := s.IsEnabled(map[string]interface{}{
+		isEnabled := s.IsEnabled(map[string]any{
 			strategy.ParamHostNames: "localhost,some-random-name",
 		}, nil)
 
@@ -65,7 +65,7 @@ func TestApplicationHostnameStrategy_IsEnabled(t *testing.T) {
 		// needed to re-read env-var
 		s = NewApplicationHostnameStrategy()
 
-		isEnabled := s.IsEnabled(map[string]interface{}{
+		isEnabled := s.IsEnabled(map[string]any{
 			strategy.ParamHostNames: "localhost,some-random-name",
 		}, nil)
 
diff --git a/internal/strategies/default.go b/internal/strategies/default.go
index fdedd04..38a2650 100644
--- a/internal/strategies/default.go
+++ b/internal/strategies/default.go
@@ -12,6 +12,6 @@ func (s defaultStrategy) Name() string {
 	return "default"
 }
 
-func (s defaultStrategy) IsEnabled(_ map[string]interface{}, _ *context.Context) bool {
+func (s defaultStrategy) IsEnabled(_ map[string]any, _ *context.Context) bool {
 	return true
 }
diff --git a/internal/strategies/flexible_rollout.go b/internal/strategies/flexible_rollout.go
index 7dc8caa..3ddfcb6 100644
--- a/internal/strategies/flexible_rollout.go
+++ b/internal/strategies/flexible_rollout.go
@@ -39,7 +39,7 @@ func (s flexibleRolloutStrategy) resolveStickiness(st stickiness, ctx context.Co
 	}
 }
 
-func (s flexibleRolloutStrategy) IsEnabled(params map[string]interface{}, ctx *context.Context) bool {
+func (s flexibleRolloutStrategy) IsEnabled(params map[string]any, ctx *context.Context) bool {
 	groupID := ""
 	if gID, found := params[strategy.ParamGroupId]; found {
 		groupID = gID.(string)
diff --git a/internal/strategies/flexible_rollout_test.go b/internal/strategies/flexible_rollout_test.go
index 263c291..a4a0e35 100644
--- a/internal/strategies/flexible_rollout_test.go
+++ b/internal/strategies/flexible_rollout_test.go
@@ -4,6 +4,7 @@
 package strategies
 
 import (
+	"math"
 	"testing"
 
 	"github.com/Unleash/unleash-go-sdk/v5/context"
@@ -29,7 +30,7 @@ func TestFlexibleRolloutStrategy_IsWellDistributed(t *testing.T) {
 		}
 	}
 
-	actualPercentage := round(100.0 * float64(enabledCount) / float64(rounds))
+	actualPercentage := math.Round(100.0 * float64(enabledCount) / float64(rounds))
 
 	assert.InDelta(t, 50, actualPercentage, 1.0)
 }
diff --git a/internal/strategies/gradual_rollout_random.go b/internal/strategies/gradual_rollout_random.go
index 4855a7e..3aeaf9c 100644
--- a/internal/strategies/gradual_rollout_random.go
+++ b/internal/strategies/gradual_rollout_random.go
@@ -20,7 +20,7 @@ func (s gradualRolloutRandomStrategy) Name() string {
 	return "gradualRolloutRandom"
 }
 
-func (s gradualRolloutRandomStrategy) IsEnabled(params map[string]interface{}, _ *context.Context) bool {
+func (s gradualRolloutRandomStrategy) IsEnabled(params map[string]any, _ *context.Context) bool {
 	value, found := params[strategy.ParamPercentage]
 	if !found {
 		return false
diff --git a/internal/strategies/gradual_rollout_random_test.go b/internal/strategies/gradual_rollout_random_test.go
index a780ac8..47fc162 100644
--- a/internal/strategies/gradual_rollout_random_test.go
+++ b/internal/strategies/gradual_rollout_random_test.go
@@ -4,6 +4,7 @@
 package strategies
 
 import (
+	"math"
 	"strconv"
 	"testing"
 
@@ -40,7 +41,7 @@ func TestGradualRolloutRandomStrategy_IsEnabled(t *testing.T) {
 			}
 		}
 
-		actualPercentage := round(100.0 * float64(enabledCount) / float64(rounds))
+		actualPercentage := math.Round(100.0 * float64(enabledCount) / float64(rounds))
 
 		assert.InDelta(t, expectedPercentage, actualPercentage, 1.0)
 	}
diff --git a/internal/strategies/gradual_rollout_session_id.go b/internal/strategies/gradual_rollout_session_id.go
index d3bfe14..7cb774e 100644
--- a/internal/strategies/gradual_rollout_session_id.go
+++ b/internal/strategies/gradual_rollout_session_id.go
@@ -17,7 +17,7 @@ func (s gradualRolloutSessionId) Name() string {
 	return "gradualRolloutSessionId"
 }
 
-func (s gradualRolloutSessionId) IsEnabled(params map[string]interface{}, ctx *context.Context) bool {
+func (s gradualRolloutSessionId) IsEnabled(params map[string]any, ctx *context.Context) bool {
 	if ctx == nil || ctx.SessionId == "" {
 		return false
 	}
diff --git a/internal/strategies/gradual_rollout_session_id_test.go b/internal/strategies/gradual_rollout_session_id_test.go
index 0acbb75..b262d3f 100644
--- a/internal/strategies/gradual_rollout_session_id_test.go
+++ b/internal/strategies/gradual_rollout_session_id_test.go
@@ -4,6 +4,7 @@
 package strategies
 
 import (
+	"math"
 	"strconv"
 	"testing"
 
@@ -95,7 +96,7 @@ func TestGradualRolloutSessionId_IsEnabled(t *testing.T) {
 				}
 			}
 
-			actualPercentage := round(100.0 * float64(enabledCount) / float64(rounds))
+			actualPercentage := math.Round(100.0 * float64(enabledCount) / float64(rounds))
 
 			assert.InDelta(expectedPercentage, actualPercentage, 1.0)
 		}
diff --git a/internal/strategies/gradual_rollout_user_id.go b/internal/strategies/gradual_rollout_user_id.go
index 8106027..93d5e74 100644
--- a/internal/strategies/gradual_rollout_user_id.go
+++ b/internal/strategies/gradual_rollout_user_id.go
@@ -17,7 +17,7 @@ func (s gradualRolloutUserId) Name() string {
 	return "gradualRolloutUserId"
 }
 
-func (s gradualRolloutUserId) IsEnabled(params map[string]interface{}, ctx *context.Context) bool {
+func (s gradualRolloutUserId) IsEnabled(params map[string]any, ctx *context.Context) bool {
 	if ctx == nil || ctx.UserId == "" {
 		return false
 	}
diff --git a/internal/strategies/gradual_rollout_user_id_test.go b/internal/strategies/gradual_rollout_user_id_test.go
index 6ecde6c..9382b15 100644
--- a/internal/strategies/gradual_rollout_user_id_test.go
+++ b/internal/strategies/gradual_rollout_user_id_test.go
@@ -4,6 +4,7 @@
 package strategies
 
 import (
+	"math"
 	"strconv"
 	"testing"
 
@@ -95,7 +96,7 @@ func TestGradualRolloutUserId_IsEnabled(t *testing.T) {
 				}
 			}
 
-			actualPercentage := round(100.0 * float64(enabledCount) / float64(rounds))
+			actualPercentage := math.Round(100.0 * float64(enabledCount) / float64(rounds))
 
 			assert.InDelta(expectedPercentage, actualPercentage, 1.0)
 		}
diff --git a/internal/strategies/helpers.go b/internal/strategies/helpers.go
index fa876c3..194c4ad 100644
--- a/internal/strategies/helpers.go
+++ b/internal/strategies/helpers.go
@@ -1,7 +1,7 @@
 package strategies
 
 import (
-	"math/rand"
+	"math/rand/v2"
 	"os"
 	"strconv"
 	"sync"
@@ -12,16 +12,6 @@ import (
 
 var VariantNormalizationSeed uint32 = 86028157
 
-func round(f float64) int {
-	if f < -0.5 {
-		return int(f - 0.5)
-	}
-	if f > 0.5 {
-		return int(f + 0.5)
-	}
-	return 0
-}
-
 func resolveHostname() (string, error) {
 	var err error
 	hostname := os.Getenv("HOSTNAME")
@@ -34,7 +24,7 @@ func resolveHostname() (string, error) {
 	return hostname, err
 }
 
-func parameterAsFloat64(param interface{}) (result float64, ok bool) {
+func parameterAsFloat64(param any) (result float64, ok bool) {
 	if f, isFloat := param.(float64); isFloat {
 		result, ok = f, true
 	} else if i, isInt := param.(int); isInt {
@@ -80,9 +70,8 @@ type rng struct {
 
 func (r *rng) int() int {
 	r.Lock()
-	n := r.random.Intn(100) + 1
-	r.Unlock()
-	return n
+	defer r.Unlock()
+	return r.random.IntN(100) + 1
 }
 
 func (r *rng) float() float64 {
@@ -91,14 +80,12 @@ func (r *rng) float() float64 {
 
 func (r *rng) string() string {
 	r.Lock()
-	n := r.random.Intn(10000) + 1
-	r.Unlock()
-	return strconv.Itoa(n)
+	defer r.Unlock()
+	return strconv.Itoa(r.random.IntN(10000) + 1)
 }
 
 // newRng creates a new random number generator and uses a mutex
 // internally to ensure safe concurrent reads.
 func newRng() *rng {
-	seed := time.Now().UnixNano() + int64(os.Getpid())
-	return &rng{random: rand.New(rand.NewSource(seed))}
+	return &rng{random: rand.New(rand.NewPCG(uint64(time.Now().UnixNano()), uint64(os.Getpid())))}
 }
diff --git a/internal/strategies/helpers_test.go b/internal/strategies/helpers_test.go
index fe24e38..8f94251 100644
--- a/internal/strategies/helpers_test.go
+++ b/internal/strategies/helpers_test.go
@@ -27,7 +27,7 @@ func TestResolveHostname(t *testing.T) {
 }
 
 func TestParameterAsFloat64(t *testing.T) {
-	goodData := map[interface{}]float64{
+	goodData := map[any]float64{
 		"30":    30.0,
 		"-0.01": -0.01,
 		42:      42.0,
@@ -42,7 +42,7 @@ func TestParameterAsFloat64(t *testing.T) {
 		assert.InDelta(t, actual, expected, 0.0000001)
 	}
 
-	badData := map[interface{}]float64{
+	badData := map[any]float64{
 		"pizza": -1.0,
 		"0.0.1": -1.0,
 	}
@@ -75,7 +75,7 @@ func TestNewRng(t *testing.T) {
 	wg := sync.WaitGroup{}
 
 	testGen := func(n int) {
-		for i := 0; i < n; i++ {
+		for range n {
 			randomInt := rng.int()
 			assert.True(t, randomInt >= 0 && randomInt <= 100)
 
@@ -90,7 +90,7 @@ func TestNewRng(t *testing.T) {
 
 	goRoutines := 20
 	wg.Add(goRoutines)
-	for j := 0; j < goRoutines; j++ {
+	for range goRoutines {
 		go testGen(100)
 	}
 	wg.Wait()
diff --git a/internal/strategies/remote_address_test.go b/internal/strategies/remote_address_test.go
index 091edfd..c605969 100644
--- a/internal/strategies/remote_address_test.go
+++ b/internal/strategies/remote_address_test.go
@@ -18,7 +18,7 @@ func TestRemoteAddressStrategy_IsEnabled(t *testing.T) {
 	assert := assert.New(t)
 
 	t.Run("r=", func(t *testing.T) {
-		var params map[string]interface{}
+		var params map[string]any
 		ctx := &context.Context{
 			RemoteAddress: "123",
 		}
@@ -26,7 +26,7 @@ func TestRemoteAddressStrategy_IsEnabled(t *testing.T) {
 	})
 
 	t.Run("r=i", func(t *testing.T) {
-		params := map[string]interface{}{
+		params := map[string]any{
 			strategy.ParamIps: "127.0.0.1",
 		}
 		ctx := &context.Context{
@@ -36,7 +36,7 @@ func TestRemoteAddressStrategy_IsEnabled(t *testing.T) {
 	})
 
 	t.Run("r!=list(i)", func(t *testing.T) {
-		params := map[string]interface{}{
+		params := map[string]any{
 			strategy.ParamIps: "127.0.1.1, 127.0.1.2, 127.0.1.3",
 		}
 		ctx := &context.Context{
@@ -46,7 +46,7 @@ func TestRemoteAddressStrategy_IsEnabled(t *testing.T) {
 	})
 
 	t.Run("r=list(i)", func(t *testing.T) {
-		params := map[string]interface{}{
+		params := map[string]any{
 			strategy.ParamIps: "127.0.0.1, 127.0.0.2,127.0.0.213",
 		}
 		ctx := &context.Context{
@@ -56,7 +56,7 @@ func TestRemoteAddressStrategy_IsEnabled(t *testing.T) {
 	})
 
 	t.Run("r=range(i)", func(t *testing.T) {
-		params := map[string]interface{}{
+		params := map[string]any{
 			strategy.ParamIps: "127.0.1.1, 127.0.1.2,127.0.1.3, 160.33.0.0/16",
 		}
 		ctx := &context.Context{
diff --git a/internal/strategies/remote_addresss.go b/internal/strategies/remote_addresss.go
index 3394da6..788b4b4 100644
--- a/internal/strategies/remote_addresss.go
+++ b/internal/strategies/remote_addresss.go
@@ -19,7 +19,7 @@ func (s remoteAddressStrategy) Name() string {
 	return "remoteAddress"
 }
 
-func (s remoteAddressStrategy) IsEnabled(params map[string]interface{}, ctx *context.Context) bool {
+func (s remoteAddressStrategy) IsEnabled(params map[string]any, ctx *context.Context) bool {
 	value, found := params[strategy.ParamIps]
 	if !found {
 		return false
diff --git a/internal/strategies/user_with_id.go b/internal/strategies/user_with_id.go
index 7ccf0f7..4e52d38 100644
--- a/internal/strategies/user_with_id.go
+++ b/internal/strategies/user_with_id.go
@@ -17,7 +17,7 @@ func (s userWithIdStrategy) Name() string {
 	return "userWithId"
 }
 
-func (s userWithIdStrategy) IsEnabled(params map[string]interface{}, ctx *context.Context) bool {
+func (s userWithIdStrategy) IsEnabled(params map[string]any, ctx *context.Context) bool {
 	value, found := params[strategy.ParamUserIds]
 	if !found {
 		return false
diff --git a/internal/strategies/user_with_id_test.go b/internal/strategies/user_with_id_test.go
index e8298e5..fd532bf 100644
--- a/internal/strategies/user_with_id_test.go
+++ b/internal/strategies/user_with_id_test.go
@@ -18,7 +18,7 @@ func TestUserWithIdStrategy_IsEnabled(t *testing.T) {
 	assert := assert.New(t)
 
 	t.Run("u=u", func(t *testing.T) {
-		params := map[string]interface{}{
+		params := map[string]any{
 			strategy.ParamUserIds: "123",
 		}
 		ctx := &context.Context{
@@ -28,7 +28,7 @@ func TestUserWithIdStrategy_IsEnabled(t *testing.T) {
 	})
 
 	t.Run("u=list(a, u)", func(t *testing.T) {
-		params := map[string]interface{}{
+		params := map[string]any{
 			strategy.ParamUserIds: "123, 122, 12312312",
 		}
 		ctx := &context.Context{
@@ -38,7 +38,7 @@ func TestUserWithIdStrategy_IsEnabled(t *testing.T) {
 	})
 
 	t.Run("u!=list(a, b)", func(t *testing.T) {
-		params := map[string]interface{}{
+		params := map[string]any{
 			strategy.ParamUserIds: "123, 122, 122",
 		}
 		ctx := &context.Context{
@@ -48,7 +48,7 @@ func TestUserWithIdStrategy_IsEnabled(t *testing.T) {
 	})
 
 	t.Run("u=list(a,u)", func(t *testing.T) {
-		params := map[string]interface{}{
+		params := map[string]any{
 			strategy.ParamUserIds: "123,122,12312312",
 		}
 		ctx := &context.Context{
@@ -57,7 +57,7 @@ func TestUserWithIdStrategy_IsEnabled(t *testing.T) {
 		assert.True(s.IsEnabled(params, ctx), "user-with-id-strategy should be enabled for userId in list")
 	})
 	t.Run("u=empty", func(t *testing.T) {
-		params := map[string]interface{}{
+		params := map[string]any{
 			strategy.ParamUserIds: "",
 		}
 		ctx := &context.Context{}
diff --git a/metrics.go b/metrics.go
index edce0a6..56abe80 100644
--- a/metrics.go
+++ b/metrics.go
@@ -249,7 +249,7 @@ func (m *metrics) sendMetrics() {
 	}
 }
 
-func (m *metrics) doPost(url *url.URL, payload interface{}) (*http.Response, error) {
+func (m *metrics) doPost(url *url.URL, payload any) (*http.Response, error) {
 	var body bytes.Buffer
 	enc := json.NewEncoder(&body)
 	if err := enc.Encode(payload); err != nil {
@@ -313,7 +313,7 @@ func (m *metrics) countVariants(name string, enabled bool, variantName string) {
 	m.bucketMu.Lock()
 	defer m.bucketMu.Unlock()
 
-	t, _ := m.bucket.Toggles[name]
+	t := m.bucket.Toggles[name]
 	if len(t.Variants) == 0 {
 		t.Variants = make(map[string]int32)
 	}
diff --git a/metrics_test.go b/metrics_test.go
index d45c94e..a0617f1 100644
--- a/metrics_test.go
+++ b/metrics_test.go
@@ -288,7 +288,7 @@ func TestMetrics_ShouldNotCountMetricsForParentToggles(t *testing.T) {
 							Id:          1,
 							Name:        "flexibleRollout",
 							Constraints: []api.Constraint{},
-							Parameters: map[string]interface{}{
+							Parameters: map[string]any{
 								"rollout":    100,
 								"stickiness": "default",
 							},
@@ -304,7 +304,7 @@ func TestMetrics_ShouldNotCountMetricsForParentToggles(t *testing.T) {
 							Id:          1,
 							Name:        "flexibleRollout",
 							Constraints: []api.Constraint{},
-							Parameters: map[string]interface{}{
+							Parameters: map[string]any{
 								"rollout":    100,
 								"stickiness": "default",
 							},
@@ -540,7 +540,7 @@ func TestMetrics_metricsData_includes_new_metadata(t *testing.T) {
 							Id:          1,
 							Name:        "flexibleRollout",
 							Constraints: []api.Constraint{},
-							Parameters: map[string]interface{}{
+							Parameters: map[string]any{
 								"rollout":    100,
 								"stickiness": "default",
 							},
@@ -556,7 +556,7 @@ func TestMetrics_metricsData_includes_new_metadata(t *testing.T) {
 							Id:          1,
 							Name:        "flexibleRollout",
 							Constraints: []api.Constraint{},
-							Parameters: map[string]interface{}{
+							Parameters: map[string]any{
 								"rollout":    100,
 								"stickiness": "default",
 							},
diff --git a/repository.go b/repository.go
index 6f00d5c..7e45b62 100644
--- a/repository.go
+++ b/repository.go
@@ -222,11 +222,14 @@ func (r *repository) fetch() error {
 	}
 
 	r.Lock()
+	defer r.Unlock()
 	r.etag = resp.Header.Get("Etag")
 	r.segments = featureResp.SegmentsMap()
-	r.options.storage.Reset(featureResp.FeatureMap(), true)
+	if err := r.options.storage.Reset(featureResp.FeatureMap(), true); err != nil {
+		return fmt.Errorf("resetting storage: %w", err)
+	}
 	r.successfulFetch()
-	r.Unlock()
+
 	return nil
 }
 
diff --git a/storage.go b/storage.go
index 675eee6..6eab760 100644
--- a/storage.go
+++ b/storage.go
@@ -20,7 +20,7 @@ type Storage interface {
 	// Reset is called after the repository has fetched the feature toggles from the server.
 	// If persist is true the implementation of this function should call Persist(). The data
 	// passed in here should be owned by the implementer of this interface.
-	Reset(data map[string]interface{}, persist bool) error
+	Reset(data map[string]any, persist bool) error
 
 	// Load is called to load the data from persistent storage and hold it in memory for fast
 	// querying.
@@ -30,27 +30,27 @@ type Storage interface {
 	Persist() error
 
 	// Get returns the data for the specified feature toggle.
-	Get(string) (interface{}, bool)
+	Get(string) (any, bool)
 
 	// List returns a list of all feature toggles.
-	List() []interface{}
+	List() []any
 }
 
 // DefaultStorage is a default Storage implementation.
 type DefaultStorage struct {
 	appName string
 	path    string
-	data    map[string]interface{}
+	data    map[string]any
 }
 
 func (ds *DefaultStorage) Init(backupPath, appName string) {
 	ds.appName = appName
 	ds.path = filepath.Join(backupPath, fmt.Sprintf("unleash-repo-schema-v1-%s.json", appName))
-	ds.data = map[string]interface{}{}
+	ds.data = map[string]any{}
 	ds.Load()
 }
 
-func (ds *DefaultStorage) Reset(data map[string]interface{}, persist bool) error {
+func (ds *DefaultStorage) Reset(data map[string]any, persist bool) error {
 	ds.data = data
 	if persist {
 		return ds.Persist()
@@ -88,13 +88,13 @@ func (ds *DefaultStorage) Persist() error {
 	return nil
 }
 
-func (ds DefaultStorage) Get(key string) (interface{}, bool) {
+func (ds DefaultStorage) Get(key string) (any, bool) {
 	val, ok := ds.data[key]
 	return val, ok
 }
 
-func (ds *DefaultStorage) List() []interface{} {
-	var features []interface{}
+func (ds *DefaultStorage) List() []any {
+	var features []any
 	for _, val := range ds.data {
 		features = append(features, val)
 	}
diff --git a/strategy/strategy.go b/strategy/strategy.go
index ec8d630..abd53b8 100644
--- a/strategy/strategy.go
+++ b/strategy/strategy.go
@@ -33,5 +33,5 @@ type Strategy interface {
 	// IsEnabled should look at the map of parameters and optionally
 	// the supplied context and return true if the feature should be
 	// enabled.
-	IsEnabled(map[string]interface{}, *context.Context) bool
+	IsEnabled(map[string]any, *context.Context) bool
 }
diff --git a/unleash_mock.go b/unleash_mock.go
index ae995d5..e891aba 100644
--- a/unleash_mock.go
+++ b/unleash_mock.go
@@ -49,7 +49,7 @@ func (l *MockedListener) OnImpression(event ImpressionEvent) {
 	l.Called(event)
 }
 
-func writeJSON(rw http.ResponseWriter, x interface{}) {
+func writeJSON(rw http.ResponseWriter, x any) {
 	enc := json.NewEncoder(rw)
 	if err := enc.Encode(x); err != nil {
 		panic(err)
diff --git a/utils.go b/utils.go
index 6488040..f281b72 100644
--- a/utils.go
+++ b/utils.go
@@ -3,12 +3,10 @@ package unleash
 import (
 	cryptoRand "crypto/rand"
 	"fmt"
-	"math/rand"
+	"math/rand/v2"
 	"os"
 	"os/user"
-	"reflect"
 	"sync"
-	"time"
 )
 
 func getTmpDirPath() string {
@@ -21,8 +19,7 @@ func generateInstanceId() string {
 	if user, err := user.Current(); err == nil && user.Username != "" {
 		prefix = user.Username
 	} else {
-		rand.Seed(time.Now().Unix())
-		prefix = fmt.Sprintf("generated-%d-%d", rand.Intn(1000000), os.Getpid())
+		prefix = fmt.Sprintf("generated-%d-%d", rand.N(1000000), os.Getpid())
 	}
 
 	if hostname, err := os.Hostname(); err == nil && hostname != "" {
@@ -58,15 +55,6 @@ func getFetchURLPath(projectName string) string {
 	return "./client/features"
 }
 
-func contains(arr []string, str string) bool {
-	for _, item := range arr {
-		if item == str {
-			return true
-		}
-	}
-	return false
-}
-
 // WarnOnce is a type for handling warnings that should only be displayed once.
 type WarnOnce struct {
 	once sync.Once
@@ -79,20 +67,13 @@ func (wo *WarnOnce) Warn(message string) {
 	})
 }
 
-func every(slice interface{}, condition func(interface{}) bool) bool {
-	sliceValue := reflect.ValueOf(slice)
-
-	if sliceValue.Kind() != reflect.Slice {
-		fmt.Println("Input is not a slice returning false")
+// every returns true iff condition returns true for all elements in the input slice.
+// This function will return false for empty slices (unlike the convention used in mathematical logic).
+func every[T any](slice []T, condition func(T) bool) bool {
+	if len(slice) == 0 {
 		return false
 	}
-
-	if sliceValue.Len() == 0 {
-		return false
-	}
-
-	for i := 0; i < sliceValue.Len(); i++ {
-		element := sliceValue.Index(i).Interface()
+	for _, element := range slice {
 		if !condition(element) {
 			return false
 		}
diff --git a/utils_test.go b/utils_test.go
index c66ba5b..80a7bcb 100644
--- a/utils_test.go
+++ b/utils_test.go
@@ -1,6 +1,7 @@
 package unleash
 
 import (
+	"slices"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -19,13 +20,8 @@ func TestGetFetchURLPath(t *testing.T) {
 func TestEvery(t *testing.T) {
 	t.Run("All Even Integers", func(t *testing.T) {
 		numbers := []int{2, 4, 6, 8, 10}
-		allEven := every(numbers, func(item interface{}) bool {
-			num, ok := item.(int)
-			if !ok {
-				t.Errorf("Expected an integer, got %T", item)
-				return false
-			}
-			return num%2 == 0
+		allEven := every(numbers, func(item int) bool {
+			return item%2 == 0
 		})
 		if !allEven {
 			t.Errorf("Expected all numbers to be even, but got false")
@@ -34,13 +30,8 @@ func TestEvery(t *testing.T) {
 
 	t.Run("All Long Strings", func(t *testing.T) {
 		words := []string{"apple", "banana", "cherry"}
-		allLong := every(words, func(item interface{}) bool {
-			str, ok := item.(string)
-			if !ok {
-				t.Errorf("Expected a string, got %T", item)
-				return false
-			}
-			return len(str) > 3
+		allLong := every(words, func(item string) bool {
+			return len(item) > 3
 		})
 		if !allLong {
 			t.Errorf("Expected all words to be long, but got false")
@@ -49,7 +40,7 @@ func TestEvery(t *testing.T) {
 
 	t.Run("Empty Slice", func(t *testing.T) {
 		emptySlice := []int{}
-		allEmpty := every(emptySlice, func(item interface{}) bool {
+		allEmpty := every(emptySlice, func(item int) bool {
 			// This condition should not be reached for an empty slice.
 			t.Errorf("Unexpected condition reached")
 			return false
@@ -60,27 +51,10 @@ func TestEvery(t *testing.T) {
 		}
 	})
 
-	t.Run("invalid inout", func(t *testing.T) {
-		invalidInput := "string"
-		result := every(invalidInput, func(item interface{}) bool {
-			// This condition should not be reached for an empty slice.
-			return true
-		})
-
-		if result == true {
-			t.Errorf("Expected result to be false")
-		}
-	})
-
 	t.Run("Result should be false if one doesn't match the predicate", func(t *testing.T) {
 		words := []string{"apple", "banana", "cherry", "he"}
-		allLong := every(words, func(item interface{}) bool {
-			str, ok := item.(string)
-			if !ok {
-				t.Errorf("Expected a string, got %T", item)
-				return false
-			}
-			return len(str) > 3
+		allLong := every(words, func(item string) bool {
+			return len(item) > 3
 		})
 		if allLong == true {
 			t.Errorf("Expected all words to be long, but got false")
@@ -92,7 +66,7 @@ func TestContains(t *testing.T) {
 	t.Run("Element is present in the slice", func(t *testing.T) {
 		arr := []string{"apple", "banana", "cherry", "date", "fig"}
 		str := "banana"
-		result := contains(arr, str)
+		result := slices.Contains(arr, str)
 		if !result {
 			t.Errorf("Expected '%s' to be in the slice, but it was not found", str)
 		}
@@ -101,7 +75,7 @@ func TestContains(t *testing.T) {
 	t.Run("Element is not present in the slice", func(t *testing.T) {
 		arr := []string{"apple", "banana", "cherry", "date", "fig"}
 		str := "grape"
-		result := contains(arr, str)
+		result := slices.Contains(arr, str)
 		if result {
 			t.Errorf("Expected '%s' not to be in the slice, but it was found", str)
 		}
@@ -110,7 +84,7 @@ func TestContains(t *testing.T) {
 	t.Run("Empty slice should return false", func(t *testing.T) {
 		arr := []string{}
 		str := "apple"
-		result := contains(arr, str)
+		result := slices.Contains(arr, str)
 		if result {
 			t.Errorf("Expected an empty slice to return false, but it returned true")
 		}
@@ -118,7 +92,7 @@ func TestContains(t *testing.T) {
 }
 
 func TestGetConnectionId(t *testing.T) {
-	for i := 0; i < 100; i++ {
+	for range 100 {
 		uuid := getConnectionId()
 
 		t.Run("Correct length", func(t *testing.T) {