diff --git a/alerting/provider/incidentio/incidentio.go b/alerting/provider/incidentio/incidentio.go
index 6783f571..ee1bc86a 100644
--- a/alerting/provider/incidentio/incidentio.go
+++ b/alerting/provider/incidentio/incidentio.go
@@ -6,6 +6,7 @@ import (
 	"errors"
 	"fmt"
 	"io"
+	"maps"
 	"net/http"
 	"strconv"
 	"strings"
@@ -170,9 +171,7 @@ func (provider *AlertProvider) buildRequestBody(cfg *Config, ep *endpoint.Endpoi
 	// Merge metadata: cfg.Metadata + ep.ExtraLabels (if present)
 	mergedMetadata := map[string]interface{}{}
 	// Copy cfg.Metadata
-	for k, v := range cfg.Metadata {
-		mergedMetadata[k] = v
-	}
+	maps.Copy(mergedMetadata, cfg.Metadata)
 	// Add extra labels from endpoint (if present)
 	if ep.ExtraLabels != nil && len(ep.ExtraLabels) > 0 {
 		for k, v := range ep.ExtraLabels {
diff --git a/api/badge.go b/api/badge.go
index 8fa95696..7600366e 100644
--- a/api/badge.go
+++ b/api/badge.go
@@ -299,7 +299,7 @@ func getBadgeColorFromResponseTime(responseTime int, key string, cfg *config.Con
 		thresholds = endpoint.UIConfig.Badge.ResponseTime.Thresholds
 	}
 	// the threshold config requires 5 values, so we can be sure it's set here
-	for i := 0; i < 5; i++ {
+	for i := range 5 {
 		if responseTime <= thresholds[i] {
 			return badgeColors[i]
 		}
diff --git a/config/config.go b/config/config.go
index 1597e9ce..6f0b5a18 100644
--- a/config/config.go
+++ b/config/config.go
@@ -6,6 +6,7 @@ import (
 	"io/fs"
 	"os"
 	"path/filepath"
+	"slices"
 	"sort"
 	"strings"
 	"time"
@@ -136,7 +137,7 @@ func (config *Config) GetUniqueExtraMetricLabels() []string {
 			continue
 		}
 		for label := range ep.ExtraLabels {
-			if contains(labels, label) {
+			if slices.Contains(labels, label) {
 				continue
 			}
 			labels = append(labels, label)
diff --git a/config/config_test.go b/config/config_test.go
index 216cd4ec..5abfe8e7 100644
--- a/config/config_test.go
+++ b/config/config_test.go
@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"os"
 	"path/filepath"
+	"slices"
 	"testing"
 	"time"
 
@@ -2052,7 +2053,7 @@ func TestConfig_GetUniqueExtraMetricLabels(t *testing.T) {
 				t.Errorf("expected %d labels, got %d", len(tt.expected), len(labels))
 			}
 			for _, label := range tt.expected {
-				if !contains(labels, label) {
+				if !slices.Contains(labels, label) {
 					t.Errorf("expected label %s to be present", label)
 				}
 			}
diff --git a/config/endpoint/condition.go b/config/endpoint/condition.go
index 6929fd55..88b36c32 100644
--- a/config/endpoint/condition.go
+++ b/config/endpoint/condition.go
@@ -216,7 +216,7 @@ func sanitizeAndResolveNumericalWithContext(list []string, result *Result, conte
 
 func prettifyNumericalParameters(parameters []string, resolvedParameters []int64, operator string) string {
 	resolvedStrings := make([]string, 2)
-	for i := 0; i < 2; i++ {
+	for i := range 2 {
 		// Check if the parameter is a certificate or domain expiration placeholder
 		if parameters[i] == CertificateExpirationPlaceholder || parameters[i] == DomainExpirationPlaceholder {
 			// Format as duration string (convert milliseconds back to duration)
diff --git a/config/endpoint/endpoint.go b/config/endpoint/endpoint.go
index 91fc712e..0e8c77b7 100644
--- a/config/endpoint/endpoint.go
+++ b/config/endpoint/endpoint.go
@@ -7,6 +7,7 @@ import (
 	"errors"
 	"fmt"
 	"io"
+	"maps"
 	"math/rand"
 	"net"
 	"net/http"
@@ -489,9 +490,7 @@ func (e *Endpoint) call(result *Result) {
 	} else if endpointType == TypeWS {
 		wsHeaders := map[string]string{}
 		if e.Headers != nil {
-			for k, v := range e.Headers {
-				wsHeaders[k] = v
-			}
+			maps.Copy(wsHeaders, e.Headers)
 		}
 		if !hasHeader(wsHeaders, UserAgentHeader) {
 			wsHeaders[UserAgentHeader] = GatusUserAgent
diff --git a/config/endpoint/result.go b/config/endpoint/result.go
index e2561f0e..ca3fbdfb 100644
--- a/config/endpoint/result.go
+++ b/config/endpoint/result.go
@@ -1,6 +1,7 @@
 package endpoint
 
 import (
+	"slices"
 	"time"
 )
 
@@ -66,11 +67,7 @@ type Result struct {
 // AddError adds an error to the result's list of errors.
 // It also ensures that there are no duplicates.
 func (r *Result) AddError(error string) {
-	for _, resultError := range r.Errors {
-		if resultError == error {
-			// If the error already exists, don't add it
-			return
-		}
+	if !slices.Contains(r.Errors, error) {
+		r.Errors = append(r.Errors, error+"")
 	}
-	r.Errors = append(r.Errors, error+"")
 }
diff --git a/config/gontext/gontext_test.go b/config/gontext/gontext_test.go
index a29bbe4d..39628166 100644
--- a/config/gontext/gontext_test.go
+++ b/config/gontext/gontext_test.go
@@ -340,9 +340,9 @@ func TestGontext_ConcurrentAccess(t *testing.T) {
 	done := make(chan bool, 10)
 
 	// Start 5 goroutines that read values
-	for i := 0; i < 5; i++ {
+	for i := range 5 {
 		go func(id int) {
-			for j := 0; j < 100; j++ {
+			for range 100 {
 				_, err := ctx.Get("counter")
 				if err != nil {
 					t.Errorf("Reader %d error: %v", id, err)
@@ -353,9 +353,9 @@ func TestGontext_ConcurrentAccess(t *testing.T) {
 	}
 
 	// Start 5 goroutines that write values
-	for i := 0; i < 5; i++ {
+	for i := range 5 {
 		go func(id int) {
-			for j := 0; j < 100; j++ {
+			for j := range 100 {
 				err := ctx.Set("counter", id*1000+j)
 				if err != nil {
 					t.Errorf("Writer %d error: %v", id, err)
@@ -366,7 +366,7 @@ func TestGontext_ConcurrentAccess(t *testing.T) {
 	}
 
 	// Wait for all goroutines to complete
-	for i := 0; i < 10; i++ {
+	for range 10 {
 		<-done
 	}
 }
diff --git a/config/maintenance/maintenance.go b/config/maintenance/maintenance.go
index 5483d607..0e0c50f4 100644
--- a/config/maintenance/maintenance.go
+++ b/config/maintenance/maintenance.go
@@ -3,6 +3,7 @@ package maintenance
 import (
 	"errors"
 	"fmt"
+	"slices"
 	"strconv"
 	"strings"
 	"time"
@@ -70,13 +71,7 @@ func (c *Config) ValidateAndSetDefaults() error {
 		return nil
 	}
 	for _, day := range c.Every {
-		isDayValid := false
-		for _, longDayName := range longDayNames {
-			if day == longDayName {
-				isDayValid = true
-				break
-			}
-		}
+		isDayValid := slices.Contains(longDayNames, day)
 		if !isDayValid {
 			return errInvalidDayName
 		}
@@ -118,7 +113,7 @@ func (c *Config) IsUnderMaintenance() bool {
 	// Set to midnight prior to adding duration
 	dayWhereMaintenancePeriodWouldStart := time.Date(now.Year(), now.Month(), adjustedDate, 0, 0, 0, 0, now.Location())
 	hasMaintenanceEveryDay := len(c.Every) == 0
-	hasMaintenancePeriodScheduledToStartOnThatWeekday := c.hasDay(dayWhereMaintenancePeriodWouldStart.Weekday().String())
+	hasMaintenancePeriodScheduledToStartOnThatWeekday := slices.Contains(c.Every, dayWhereMaintenancePeriodWouldStart.Weekday().String())
 	if !hasMaintenanceEveryDay && !hasMaintenancePeriodScheduledToStartOnThatWeekday {
 		// The day when the maintenance period would start is not scheduled
 		// to have any maintenance, so we can just return false.
@@ -129,15 +124,6 @@ func (c *Config) IsUnderMaintenance() bool {
 	return now.After(startOfMaintenancePeriod) && now.Before(endOfMaintenancePeriod)
 }
 
-func (c *Config) hasDay(day string) bool {
-	for _, d := range c.Every {
-		if d == day {
-			return true
-		}
-	}
-	return false
-}
-
 func hhmmToDuration(s string) (time.Duration, error) {
 	if len(s) != 5 {
 		return 0, errInvalidMaintenanceStartFormat
diff --git a/config/tunneling/sshtunnel/sshtunnel.go b/config/tunneling/sshtunnel/sshtunnel.go
index 964d5089..1d6f4e5f 100644
--- a/config/tunneling/sshtunnel/sshtunnel.go
+++ b/config/tunneling/sshtunnel/sshtunnel.go
@@ -133,7 +133,7 @@ func (t *SSHTunnel) Dial(network, addr string) (net.Conn, error) {
 	const maxRetries = 3
 	const baseDelay = 500 * time.Millisecond
 	var lastErr error
-	for attempt := 0; attempt < maxRetries; attempt++ {
+	for attempt := range maxRetries {
 		if attempt > 0 {
 			// Exponential backoff: 500ms, 1s, 2s
 			delay := baseDelay << (attempt - 1)
diff --git a/config/util.go b/config/util.go
index cffeaf0f..280212a9 100644
--- a/config/util.go
+++ b/config/util.go
@@ -4,13 +4,3 @@ package config
 func toPtr[T any](value T) *T {
 	return &value
 }
-
-// contains checks if a key exists in the slice
-func contains[T comparable](slice []T, key T) bool {
-	for _, item := range slice {
-		if item == key {
-			return true
-		}
-	}
-	return false
-}
diff --git a/storage/store/memory/memory.go b/storage/store/memory/memory.go
index 79f4e505..edf5d7c3 100644
--- a/storage/store/memory/memory.go
+++ b/storage/store/memory/memory.go
@@ -1,6 +1,7 @@
 package memory
 
 import (
+	"slices"
 	"sort"
 	"sync"
 	"time"
@@ -237,13 +238,7 @@ func (s *Store) InsertSuiteResult(su *suite.Suite, result *suite.Result) error {
 func (s *Store) DeleteAllEndpointStatusesNotInKeys(keys []string) int {
 	var keysToDelete []string
 	for _, existingKey := range s.endpointCache.GetKeysByPattern("*", 0) {
-		shouldDelete := true
-		for _, k := range keys {
-			if existingKey == k {
-				shouldDelete = false
-				break
-			}
-		}
+		shouldDelete := !slices.Contains(keys, existingKey)
 		if shouldDelete {
 			keysToDelete = append(keysToDelete, existingKey)
 		}
diff --git a/storage/store/memory/memory_test.go b/storage/store/memory/memory_test.go
index 7a1176c1..e5353e9d 100644
--- a/storage/store/memory/memory_test.go
+++ b/storage/store/memory/memory_test.go
@@ -797,7 +797,7 @@ func TestSuiteResultOrdering(t *testing.T) {
 	baseTime := time.Now().Add(-5 * time.Hour)
 	timestamps := make([]time.Time, 5)
 
-	for i := 0; i < 5; i++ {
+	for i := range 5 {
 		timestamp := baseTime.Add(time.Duration(i) * time.Hour)
 		timestamps[i] = timestamp
 		result := &suite.Result{
@@ -878,7 +878,7 @@ func TestSuiteResultOrdering(t *testing.T) {
 		smallSuite := &suite.Suite{Name: "small-suite", Group: "test"}
 
 		// Insert 6 results, should keep only the newest 3
-		for i := 0; i < 6; i++ {
+		for i := range 6 {
 			result := &suite.Result{
 				Name:      smallSuite.Name,
 				Group:     smallSuite.Group,
@@ -925,7 +925,7 @@ func TestStore_ConcurrentAccess(t *testing.T) {
 
 		// Create endpoints for concurrent testing
 		endpoints := make([]*endpoint.Endpoint, numGoroutines)
-		for i := 0; i < numGoroutines; i++ {
+		for i := range numGoroutines {
 			endpoints[i] = &endpoint.Endpoint{
 				Name:  "endpoint-" + string(rune('A'+i)),
 				Group: "concurrent",
@@ -934,12 +934,12 @@ func TestStore_ConcurrentAccess(t *testing.T) {
 		}
 
 		// Concurrently insert results for different endpoints
-		for i := 0; i < numGoroutines; i++ {
+		for i := range numGoroutines {
 			wg.Add(1)
 			go func(endpointIndex int) {
 				defer wg.Done()
 				ep := endpoints[endpointIndex]
-				for j := 0; j < resultsPerGoroutine; j++ {
+				for j := range resultsPerGoroutine {
 					result := &endpoint.Result{
 						Success:   j%2 == 0,
 						Timestamp: time.Now().Add(time.Duration(j) * time.Minute),
@@ -978,7 +978,7 @@ func TestStore_ConcurrentAccess(t *testing.T) {
 
 		// Create suites for concurrent testing
 		suites := make([]*suite.Suite, numGoroutines)
-		for i := 0; i < numGoroutines; i++ {
+		for i := range numGoroutines {
 			suites[i] = &suite.Suite{
 				Name:  "suite-" + string(rune('A'+i)),
 				Group: "concurrent",
@@ -986,12 +986,12 @@ func TestStore_ConcurrentAccess(t *testing.T) {
 		}
 
 		// Concurrently insert results for different suites
-		for i := 0; i < numGoroutines; i++ {
+		for i := range numGoroutines {
 			wg.Add(1)
 			go func(suiteIndex int) {
 				defer wg.Done()
 				su := suites[suiteIndex]
-				for j := 0; j < resultsPerGoroutine; j++ {
+				for j := range resultsPerGoroutine {
 					result := &suite.Result{
 						Name:      su.Name,
 						Group:     su.Group,
@@ -1036,7 +1036,7 @@ func TestStore_ConcurrentAccess(t *testing.T) {
 		wg.Add(1)
 		go func() {
 			defer wg.Done()
-			for i := 0; i < 5; i++ {
+			for i := range 5 {
 				result := &endpoint.Result{
 					Success:   true,
 					Timestamp: time.Now(),
@@ -1050,7 +1050,7 @@ func TestStore_ConcurrentAccess(t *testing.T) {
 		wg.Add(1)
 		go func() {
 			defer wg.Done()
-			for i := 0; i < 5; i++ {
+			for i := range 5 {
 				result := &suite.Result{
 					Name:      testSuite.Name,
 					Group:     testSuite.Group,
@@ -1066,7 +1066,7 @@ func TestStore_ConcurrentAccess(t *testing.T) {
 		wg.Add(1)
 		go func() {
 			defer wg.Done()
-			for i := 0; i < 10; i++ {
+			for range 10 {
 				store.GetAllEndpointStatuses(&paging.EndpointStatusParams{})
 				store.GetAllSuiteStatuses(&paging.SuiteStatusParams{})
 				time.Sleep(1 * time.Millisecond)
diff --git a/storage/store/memory/util_bench_test.go b/storage/store/memory/util_bench_test.go
index d8f1d26a..2a81f4e6 100644
--- a/storage/store/memory/util_bench_test.go
+++ b/storage/store/memory/util_bench_test.go
@@ -11,10 +11,10 @@ import (
 func BenchmarkShallowCopyEndpointStatus(b *testing.B) {
 	ep := &testEndpoint
 	status := endpoint.NewStatus(ep.Group, ep.Name)
-	for i := 0; i < storage.DefaultMaximumNumberOfResults; i++ {
+	for range storage.DefaultMaximumNumberOfResults {
 		AddResult(status, &testSuccessfulResult, storage.DefaultMaximumNumberOfResults, storage.DefaultMaximumNumberOfEvents)
 	}
-	for n := 0; n < b.N; n++ {
+	for b.Loop() {
 		ShallowCopyEndpointStatus(status, paging.NewEndpointStatusParams().WithResults(1, 20))
 	}
 	b.ReportAllocs()
diff --git a/storage/store/memory/util_test.go b/storage/store/memory/util_test.go
index 927ca937..dd09d5b4 100644
--- a/storage/store/memory/util_test.go
+++ b/storage/store/memory/util_test.go
@@ -13,7 +13,7 @@ import (
 func TestAddResult(t *testing.T) {
 	ep := &endpoint.Endpoint{Name: "name", Group: "group"}
 	endpointStatus := endpoint.NewStatus(ep.Group, ep.Name)
-	for i := 0; i < (storage.DefaultMaximumNumberOfResults+storage.DefaultMaximumNumberOfEvents)*2; i++ {
+	for i := range (storage.DefaultMaximumNumberOfResults + storage.DefaultMaximumNumberOfEvents) * 2 {
 		AddResult(endpointStatus, &endpoint.Result{Success: i%2 == 0, Timestamp: time.Now()}, storage.DefaultMaximumNumberOfResults, storage.DefaultMaximumNumberOfEvents)
 	}
 	if len(endpointStatus.Results) != storage.DefaultMaximumNumberOfResults {
@@ -30,7 +30,7 @@ func TestShallowCopyEndpointStatus(t *testing.T) {
 	ep := &endpoint.Endpoint{Name: "name", Group: "group"}
 	endpointStatus := endpoint.NewStatus(ep.Group, ep.Name)
 	ts := time.Now().Add(-25 * time.Hour)
-	for i := 0; i < 25; i++ {
+	for i := range 25 {
 		AddResult(endpointStatus, &endpoint.Result{Success: i%2 == 0, Timestamp: ts}, storage.DefaultMaximumNumberOfResults, storage.DefaultMaximumNumberOfEvents)
 		ts = ts.Add(time.Hour)
 	}
@@ -74,9 +74,9 @@ func TestShallowCopySuiteStatus(t *testing.T) {
 		Key:     testSuite.Key(),
 		Results: []*suite.Result{},
 	}
-	
+
 	ts := time.Now().Add(-25 * time.Hour)
-	for i := 0; i < 25; i++ {
+	for i := range 25 {
 		result := &suite.Result{
 			Name:      testSuite.Name,
 			Group:     testSuite.Group,
@@ -169,4 +169,3 @@ func TestShallowCopySuiteStatus(t *testing.T) {
 		}
 	})
 }
-
diff --git a/storage/store/sql/sql_test.go b/storage/store/sql/sql_test.go
index 9cbaf492..b776f7a5 100644
--- a/storage/store/sql/sql_test.go
+++ b/storage/store/sql/sql_test.go
@@ -900,7 +900,7 @@ func TestEventOrderingFix(t *testing.T) {
 	}
 	// Create many events over time
 	baseTime := time.Now().Add(-100 * time.Hour) // Start 100 hours ago
-	for i := 0; i < 50; i++ {
+	for i := range 50 {
 		result := &endpoint.Result{
 			Success:   i%2 == 0, // Alternate between true/false to create events
 			Timestamp: baseTime.Add(time.Duration(i) * time.Hour),
diff --git a/storage/store/store_bench_test.go b/storage/store/store_bench_test.go
index c3f53f75..d02f715e 100644
--- a/storage/store/store_bench_test.go
+++ b/storage/store/store_bench_test.go
@@ -53,11 +53,11 @@ func BenchmarkStore_GetAllEndpointStatuses(b *testing.B) {
 		numberOfEndpoints := []int{10, 25, 50, 100}
 		for _, numberOfEndpointsToCreate := range numberOfEndpoints {
 			// Create endpoints and insert results
-			for i := 0; i < numberOfEndpointsToCreate; i++ {
+			for i := range numberOfEndpointsToCreate {
 				ep := testEndpoint
 				ep.Name = "endpoint" + strconv.Itoa(i)
 				// InsertEndpointResult 20 results for each endpoint
-				for j := 0; j < 20; j++ {
+				for range 20 {
 					scenario.Store.InsertEndpointResult(&ep, &testSuccessfulResult)
 				}
 			}
@@ -191,7 +191,7 @@ func BenchmarkStore_GetEndpointStatusByKey(b *testing.B) {
 		},
 	}
 	for _, scenario := range scenarios {
-		for i := 0; i < 50; i++ {
+		for range 50 {
 			scenario.Store.InsertEndpointResult(&testEndpoint, &testSuccessfulResult)
 			scenario.Store.InsertEndpointResult(&testEndpoint, &testUnsuccessfulResult)
 		}