diff --git a/api/globalconfig/types.go b/api/globalconfig/types.go
index 631b4e4e2..eace135f8 100644
--- a/api/globalconfig/types.go
+++ b/api/globalconfig/types.go
@@ -79,7 +79,7 @@ type Go struct {
 type ModbusProxy struct {
 	Port            int    `json:"port"`
 	ReadOnly        string `yaml:",omitempty" json:"readonly,omitempty"`
-	modbus.Settings `mapstructure:",squash" yaml:",inline,omitempty" json:"settings,omitempty"`
+	modbus.Settings `mapstructure:",squash" yaml:",inline,omitempty" json:"settings"`
 }
 
 var _ api.Redactor = (*Hems)(nil)
diff --git a/core/prioritizer/prioritizer.go b/core/prioritizer/prioritizer.go
index 6cdb88866..4111fb20b 100644
--- a/core/prioritizer/prioritizer.go
+++ b/core/prioritizer/prioritizer.go
@@ -2,6 +2,7 @@ package prioritizer
 
 import (
 	"fmt"
+	"strings"
 	"sync"
 
 	"github.com/evcc-io/evcc/api"
@@ -35,18 +36,18 @@ func (p *Prioritizer) GetChargePowerFlexibility(lp loadpoint.API) float64 {
 
 	var (
 		reduceBy float64
-		msg      string
+		msg      strings.Builder
 	)
 
 	for lp, power := range p.demand {
 		if lp.EffectivePriority() < prio && power > 0 {
 			reduceBy += power
-			msg += fmt.Sprintf("%.0fW from %s at prio %d, ", power, lp.GetTitle(), lp.EffectivePriority())
+			msg.WriteString(fmt.Sprintf("%.0fW from %s at prio %d, ", power, lp.GetTitle(), lp.EffectivePriority()))
 		}
 	}
 
 	if p.log != nil && reduceBy > 0 {
-		p.log.DEBUG.Printf("lp %s at prio %d gets additional %stotal %.0fW\n", lp.GetTitle(), lp.EffectivePriority(), msg, reduceBy)
+		p.log.DEBUG.Printf("lp %s at prio %d gets additional %stotal %.0fW\n", lp.GetTitle(), lp.EffectivePriority(), msg.String(), reduceBy)
 	}
 
 	return reduceBy
diff --git a/core/site_tariffs.go b/core/site_tariffs.go
index f26a7ffd5..e39424827 100644
--- a/core/site_tariffs.go
+++ b/core/site_tariffs.go
@@ -26,11 +26,11 @@ func (s forecastSeries) MarshalBytes() ([]byte, error) {
 }
 
 type solarDetails struct {
-	Scale            float64      `json:"scale"`                      // scale factor yield/forecasted today, 1 if unscaled
-	Today            dailyDetails `json:"today,omitempty"`            // tomorrow
-	Tomorrow         dailyDetails `json:"tomorrow,omitempty"`         // tomorrow
-	DayAfterTomorrow dailyDetails `json:"dayAfterTomorrow,omitempty"` // day after tomorrow
-	Timeseries       timeseries   `json:"timeseries,omitempty"`       // timeseries of forecasted energy
+	Scale            float64      `json:"scale"`                // scale factor yield/forecasted today, 1 if unscaled
+	Today            dailyDetails `json:"today"`                // tomorrow
+	Tomorrow         dailyDetails `json:"tomorrow"`             // tomorrow
+	DayAfterTomorrow dailyDetails `json:"dayAfterTomorrow"`     // day after tomorrow
+	Timeseries       timeseries   `json:"timeseries,omitempty"` // timeseries of forecasted energy
 }
 
 var _ api.BytesMarshaler = (*solarDetails)(nil)
diff --git a/messenger/hub.go b/messenger/hub.go
index 22bf694e2..c8c78b368 100644
--- a/messenger/hub.go
+++ b/messenger/hub.go
@@ -2,6 +2,7 @@ package messenger
 
 import (
 	"fmt"
+	"maps"
 	"reflect"
 	"strings"
 	"text/template"
@@ -105,9 +106,7 @@ func (h *Hub) apply(ev Event, tmpl string) (string, error) {
 	}
 
 	// event-specific attributes override cache values
-	for k, v := range ev.Attributes {
-		attr[k] = v
-	}
+	maps.Copy(attr, ev.Attributes)
 
 	return util.ReplaceFormatted(tmpl, attr)
 }
diff --git a/meter/dsmr_test.go b/meter/dsmr_test.go
index 5ef977f95..e856b4c49 100644
--- a/meter/dsmr_test.go
+++ b/meter/dsmr_test.go
@@ -247,8 +247,7 @@ func assertReadings(t *testing.T, m api.Meter) {
 func TestDsmrTCP(t *testing.T) {
 	addr := serveTCP(t, dsmrFrame(dsmrTelegram50))
 
-	ctx, cancel := context.WithCancel(context.Background())
-	defer cancel()
+	ctx := t.Context()
 
 	m, err := NewDsmr(ctx, addr, time.Second)
 	require.NoError(t, err)
@@ -285,8 +284,7 @@ func TestDsmrWebSocket(t *testing.T) {
 
 			uri := "ws" + strings.TrimPrefix(srv.URL, "http")
 
-			ctx, cancel := context.WithCancel(context.Background())
-			defer cancel()
+			ctx := t.Context()
 
 			m, err := NewDsmr(ctx, uri, time.Second)
 			require.NoError(t, err)
@@ -307,8 +305,7 @@ func TestDsmrIgnoresGarbage(t *testing.T) {
 
 	addr := serveTCP(t, payload)
 
-	ctx, cancel := context.WithCancel(context.Background())
-	defer cancel()
+	ctx := t.Context()
 
 	m, err := NewDsmr(ctx, addr, time.Second)
 	require.NoError(t, err)
@@ -398,8 +395,7 @@ func newTestDsmr(frame map[string]string) *Dsmr {
 func TestDsmrADN(t *testing.T) {
 	addr := serveTCP(t, dsmrFrame(dsmrTelegramADN))
 
-	ctx, cancel := context.WithCancel(context.Background())
-	defer cancel()
+	ctx := t.Context()
 
 	m, err := NewDsmr(ctx, addr, time.Second)
 	require.NoError(t, err)
@@ -445,8 +441,7 @@ func TestDsmrADN(t *testing.T) {
 func TestDsmrExport(t *testing.T) {
 	addr := serveTCP(t, dsmrFrame(dsmrTelegramExport))
 
-	ctx, cancel := context.WithCancel(context.Background())
-	defer cancel()
+	ctx := t.Context()
 
 	m, err := NewDsmr(ctx, addr, time.Second)
 	require.NoError(t, err)
diff --git a/util/homeassistant/connection.go b/util/homeassistant/connection.go
index e35ee29b6..f94e5a715 100644
--- a/util/homeassistant/connection.go
+++ b/util/homeassistant/connection.go
@@ -202,7 +202,7 @@ func NewStatusMap(a, b, c string) (StatusMap, error) {
 		{api.StatusB, b},
 		{api.StatusC, c},
 	} {
-		for _, s := range strings.Split(e.states, ",") {
+		for s := range strings.SplitSeq(e.states, ",") {
 			if s = strings.ToLower(strings.TrimSpace(s)); s != "" {
 				if status, ok := res[s]; ok {
 					return nil, fmt.Errorf("status %s: duplicate state '%s', already mapped to %s", e.status, s, status)
diff --git a/util/logstash/log_test.go b/util/logstash/log_test.go
index af0c7a144..aa2614827 100644
--- a/util/logstash/log_test.go
+++ b/util/logstash/log_test.go
@@ -45,7 +45,7 @@ func TestTraceBudget(t *testing.T) {
 
 	log.Write([]byte(s2))
 	for i := range 100 {
-		log.Write([]byte(fmt.Sprintf("[mqtt  ] TRACE send %d", i)))
+		log.Write(fmt.Appendf(nil, "[mqtt  ] TRACE send %d", i))
 	}
 
 	assert.Equal(t, []string{s2}, log.All(nil, jww.LevelDebug, 0))
diff --git a/util/sponsor/auth.go b/util/sponsor/auth.go
index 63107af3e..ed225fccf 100644
--- a/util/sponsor/auth.go
+++ b/util/sponsor/auth.go
@@ -137,7 +137,7 @@ func redactToken(token string) string {
 
 type Status struct {
 	Name        string    `json:"name"`
-	ExpiresAt   time.Time `json:"expiresAt,omitempty"`
+	ExpiresAt   time.Time `json:"expiresAt"`
 	ExpiresSoon bool      `json:"expiresSoon,omitempty"`
 	Token       string    `json:"token,omitempty"`
 }
diff --git a/util/sponsor/pulsares.go b/util/sponsor/pulsares.go
index 66bf88458..f898a37ad 100644
--- a/util/sponsor/pulsares.go
+++ b/util/sponsor/pulsares.go
@@ -38,7 +38,7 @@ func checkPulsares() (string, error) {
 		_ = f.Close()
 	})
 
-	var token string
+	var token strings.Builder
 	b := make([]byte, 512)
 
 	for {
@@ -47,9 +47,9 @@ func checkPulsares() (string, error) {
 			return "", nil
 		}
 
-		token += string(b[:n])
+		token.WriteString(string(b[:n]))
 
-		if token, ok := strings.CutSuffix(token, "\x04"); ok {
+		if token, ok := strings.CutSuffix(token.String(), "\x04"); ok {
 			return token, nil
 		}
 	}
diff --git a/util/templates/types.go b/util/templates/types.go
index 55dbe208c..b106afd1b 100644
--- a/util/templates/types.go
+++ b/util/templates/types.go
@@ -327,7 +327,7 @@ func (p Param) MarshalJSON() ([]byte, error) {
 // Product contains naming information about a product a template supports
 type Product struct {
 	Brand        string       // product brand
-	Description  TextLanguage `json:",omitempty"` // product name
+	Description  TextLanguage // product name
 	Capabilities []Capability `json:",omitempty"` // appended to template-level capabilities
 }