diff --git a/assertx/assertx.go b/assertx/assertx.go
index 8b5b91ce..110b92f7 100644
--- a/assertx/assertx.go
+++ b/assertx/assertx.go
@@ -17,13 +17,15 @@ import (
 	"github.com/stretchr/testify/require"
 )
 
-func PrettifyJSONPayload(t *testing.T, payload interface{}) string {
+func PrettifyJSONPayload(t testing.TB, payload interface{}) string {
+	t.Helper()
 	o, err := json.MarshalIndent(payload, "", "  ")
 	require.NoError(t, err)
 	return string(o)
 }
 
-func EqualAsJSON(t *testing.T, expected, actual interface{}, args ...interface{}) {
+func EqualAsJSON(t testing.TB, expected, actual interface{}, args ...interface{}) {
+	t.Helper()
 	var eb, ab bytes.Buffer
 	if len(args) == 0 {
 		args = []interface{}{PrettifyJSONPayload(t, actual)}
@@ -34,7 +36,8 @@ func EqualAsJSON(t *testing.T, expected, actual interface{}, args ...interface{}
 	assert.JSONEq(t, strings.TrimSpace(eb.String()), strings.TrimSpace(ab.String()), args...)
 }
 
-func EqualAsJSONExcept(t *testing.T, expected, actual interface{}, except []string, args ...interface{}) {
+func EqualAsJSONExcept(t testing.TB, expected, actual interface{}, except []string, args ...interface{}) {
+	t.Helper()
 	var eb, ab bytes.Buffer
 	if len(args) == 0 {
 		args = []interface{}{PrettifyJSONPayload(t, actual)}
@@ -56,7 +59,7 @@ func EqualAsJSONExcept(t *testing.T, expected, actual interface{}, except []stri
 	assert.JSONEq(t, strings.TrimSpace(ebs), strings.TrimSpace(abs), args...)
 }
 
-func TimeDifferenceLess(t *testing.T, t1, t2 time.Time, seconds int) {
+func TimeDifferenceLess(t testing.TB, t1, t2 time.Time, seconds int) {
 	t.Helper()
 	delta := math.Abs(float64(t1.Unix()) - float64(t2.Unix()))
 	assert.Less(t, delta, float64(seconds))
diff --git a/cmdx/helper.go b/cmdx/helper.go
index 594bdbb0..45eb294b 100644
--- a/cmdx/helper.go
+++ b/cmdx/helper.go
@@ -10,12 +10,14 @@ import (
 	"fmt"
 	"io"
 	"net/http"
+	"net/url"
 	"os"
 	"testing"
 
 	"golang.org/x/sync/errgroup"
 
 	"github.com/spf13/cobra"
+	"github.com/spf13/pflag"
 	"github.com/stretchr/testify/require"
 
 	"github.com/pkg/errors"
@@ -25,9 +27,9 @@ import (
 
 var (
 	// ErrNilDependency is returned if a dependency is missing.
-	ErrNilDependency = errors.New("a dependency was expected to be defined but is nil. Please open an issue with the stack trace")
+	ErrNilDependency = fmt.Errorf("a dependency was expected to be defined but is nil. Please open an issue with the stack trace")
 	// ErrNoPrintButFail is returned to detect a failure state that was already reported to the user in some way
-	ErrNoPrintButFail = errors.New("this error should never be printed")
+	ErrNoPrintButFail = fmt.Errorf("this error should never be printed")
 
 	debugStdout, debugStderr = io.Discard, io.Discard
 )
@@ -48,6 +50,7 @@ func FailSilently(cmd *cobra.Command) error {
 }
 
 // Must fatals with the optional message if err is not nil.
+// Deprecated: do not use this function in commands, as it makes it impossible to test them. Instead, return the error.
 func Must(err error, message string, args ...interface{}) {
 	if err == nil {
 		return
@@ -58,6 +61,7 @@ func Must(err error, message string, args ...interface{}) {
 }
 
 // CheckResponse fatals if err is nil or the response.StatusCode does not match the expectedStatusCode
+// Deprecated: do not use this function in commands, as it makes it impossible to test them. Instead, return the error.
 func CheckResponse(err error, expectedStatusCode int, response *http.Response) {
 	Must(err, "Command failed because error occurred: %s", err)
 
@@ -85,6 +89,7 @@ Response payload:
 }
 
 // FormatResponse takes an object and prints a json.MarshalIdent version of it or fatals.
+// Deprecated: do not use this function in commands, as it makes it impossible to test them. Instead, return the error.
 func FormatResponse(o interface{}) string {
 	out, err := json.MarshalIndent(o, "", "\t")
 	Must(err, `Command failed because an error occurred while prettifying output: %s`, err)
@@ -92,6 +97,7 @@ func FormatResponse(o interface{}) string {
 }
 
 // Fatalf prints to os.Stderr and exists with code 1.
+// Deprecated: do not use this function in commands, as it makes it impossible to test them. Instead, return the error.
 func Fatalf(message string, args ...interface{}) {
 	if len(args) > 0 {
 		_, _ = fmt.Fprintf(os.Stderr, message+"\n", args...)
@@ -102,6 +108,7 @@ func Fatalf(message string, args ...interface{}) {
 }
 
 // ExpectDependency expects every dependency to be not nil or it fatals.
+// Deprecated: do not use this function in commands, as it makes it impossible to test them. Instead, return the error.
 func ExpectDependency(logger *logrusx.Logger, dependencies ...interface{}) {
 	if logger == nil {
 		panic("missing logger for dependency check")
@@ -225,3 +232,22 @@ func (c *CommandExecuter) ExecNoErr(t require.TestingT, args ...string) string {
 func (c *CommandExecuter) ExecExpectedErr(t require.TestingT, args ...string) string {
 	return ExecExpectedErrCtx(c.Ctx, t, c.New(), append(c.PersistentArgs, args...)...)
 }
+
+type URL struct {
+	url.URL
+}
+
+var _ pflag.Value = (*URL)(nil)
+
+func (u *URL) Set(s string) error {
+	uu, err := url.Parse(s)
+	if err != nil {
+		return err
+	}
+	u.URL = *uu
+	return nil
+}
+
+func (*URL) Type() string {
+	return "url"
+}
diff --git a/cmdx/printing.go b/cmdx/printing.go
index 98cd6688..bea36d03 100644
--- a/cmdx/printing.go
+++ b/cmdx/printing.go
@@ -291,26 +291,25 @@ func RegisterFormatFlags(flags *pflag.FlagSet) {
 	flags.String(FlagFormat, string(FormatDefault), fmt.Sprintf("Set the output format. One of %s, %s, %s, %s, %s and %s.", FormatTable, FormatJSON, FormatYAML, FormatJSONPretty, FormatJSONPath, FormatJSONPointer))
 }
 
-type bodyer interface {
-	Body() []byte
-}
-
 func PrintOpenAPIError(cmd *cobra.Command, err error) error {
 	if err == nil {
 		return nil
 	}
 
-	var be bodyer
+	var be interface {
+		Body() []byte
+	}
 	if !errors.As(err, &be) {
 		return err
 	}
 
-	var didPrettyPrint bool
-	if message := gjson.GetBytes(be.Body(), "error.message"); message.Exists() {
+	body := be.Body()
+	didPrettyPrint := false
+	if message := gjson.GetBytes(body, "error.message"); message.Exists() {
 		_, _ = fmt.Fprintf(cmd.ErrOrStderr(), "%s\n", message.String())
 		didPrettyPrint = true
 	}
-	if reason := gjson.GetBytes(be.Body(), "error.reason"); reason.Exists() {
+	if reason := gjson.GetBytes(body, "error.reason"); reason.Exists() {
 		_, _ = fmt.Fprintf(cmd.ErrOrStderr(), "%s\n", reason.String())
 		didPrettyPrint = true
 	}
@@ -319,7 +318,7 @@ func PrintOpenAPIError(cmd *cobra.Command, err error) error {
 		return FailSilently(cmd)
 	}
 
-	if body, err := json.MarshalIndent(json.RawMessage(be.Body()), "", "  "); err == nil {
+	if body, err := json.MarshalIndent(json.RawMessage(body), "", "  "); err == nil {
 		_, _ = fmt.Fprintf(cmd.ErrOrStderr(), "%s\nFailed to execute API request, see error above.\n", body)
 		return FailSilently(cmd)
 	}
diff --git a/cmdx/printing_test.go b/cmdx/printing_test.go
index 61ec190f..cf33cf2c 100644
--- a/cmdx/printing_test.go
+++ b/cmdx/printing_test.go
@@ -6,13 +6,12 @@ package cmdx
 import (
 	"bytes"
 	"fmt"
+	"slices"
 	"strconv"
 	"testing"
 
 	"github.com/spf13/cobra"
 
-	"github.com/ory/x/stringslice"
-
 	"github.com/spf13/pflag"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
@@ -170,8 +169,8 @@ func TestPrinting(t *testing.T) {
 					for _, s := range tc.contained {
 						assert.Contains(t, out.String(), s, "%s", out.String())
 					}
-					notContained := stringslice.Filter(allFields, func(s string) bool {
-						return stringslice.Has(tc.contained, s)
+					notContained := slices.DeleteFunc(slices.Clone(allFields), func(s string) bool {
+						return slices.Contains(tc.contained, s)
 					})
 					for _, s := range notContained {
 						assert.NotContains(t, out.String(), s, "%s", out.String())
@@ -258,8 +257,8 @@ func TestPrinting(t *testing.T) {
 					for _, s := range tc.contained {
 						assert.Contains(t, out.String(), s, "%s", out.String())
 					}
-					notContained := stringslice.Filter(allFields, func(s string) bool {
-						return stringslice.Has(tc.contained, s)
+					notContained := slices.DeleteFunc(slices.Clone(allFields), func(s string) bool {
+						return slices.Contains(tc.contained, s)
 					})
 					for _, s := range notContained {
 						assert.NotContains(t, out.String(), s, "%s", out.String())
diff --git a/fetcher/fetcher.go b/fetcher/fetcher.go
index aeda9e1a..0ae8f20e 100644
--- a/fetcher/fetcher.go
+++ b/fetcher/fetcher.go
@@ -101,7 +101,7 @@ func (f *Fetcher) FetchContext(ctx context.Context, source string) (*bytes.Buffe
 // context that is used for HTTP requests.
 func (f *Fetcher) FetchBytes(ctx context.Context, source string) ([]byte, error) {
 	switch s := stringsx.SwitchPrefix(source); {
-	case s.HasPrefix("http://"), s.HasPrefix("https://"):
+	case s.HasPrefix("http://", "https://"):
 		return f.fetchRemote(ctx, source)
 	case s.HasPrefix("file://"):
 		return f.fetchFile(strings.TrimPrefix(source, "file://"))
diff --git a/jsonschemax/keys.go b/jsonschemax/keys.go
index ea5e9e66..ab9638c1 100644
--- a/jsonschemax/keys.go
+++ b/jsonschemax/keys.go
@@ -11,14 +11,13 @@ import (
 	"fmt"
 	"math/big"
 	"regexp"
+	"slices"
 	"sort"
 	"strings"
 
 	"github.com/pkg/errors"
 
 	"github.com/ory/jsonschema/v3"
-
-	"github.com/ory/x/stringslice"
 )
 
 type (
@@ -268,7 +267,7 @@ func listPaths(schema *jsonschema.Schema, parent *jsonschema.Schema, parents []s
 						types = append(types, is.Ref.Types...)
 					}
 				}
-				types = stringslice.Unique(types)
+				types = slices.Compact(types)
 				if len(types) == 1 {
 					switch types[0] {
 					case "boolean":
diff --git a/logrusx/logrus.go b/logrusx/logrus.go
index 0cbae82b..a56ed511 100644
--- a/logrusx/logrus.go
+++ b/logrusx/logrus.go
@@ -104,7 +104,7 @@ func setFormatter(l *logrus.Logger, o *options) {
 		default:
 			unknownFormat = true
 			fallthrough
-		case format.AddCase("text"), format.AddCase(""):
+		case format.AddCase("text", ""):
 			l.Formatter = &logrus.TextFormatter{
 				DisableQuote:     true,
 				DisableTimestamp: false,
@@ -203,7 +203,7 @@ func New(name string, version string, opts ...Option) *Logger {
 		name:          name,
 		version:       version,
 		leakSensitive: o.leakSensitive || o.c.Bool("log.leak_sensitive_values"),
-		redactionText: stringsx.DefaultIfEmpty(o.redactionText, `Value is sensitive and has been redacted. To see the value set config key "log.leak_sensitive_values = true" or environment variable "LOG_LEAK_SENSITIVE_VALUES=true".`),
+		redactionText: stringsx.Coalesce(o.redactionText, `Value is sensitive and has been redacted. To see the value set config key "log.leak_sensitive_values = true" or environment variable "LOG_LEAK_SENSITIVE_VALUES=true".`),
 		Entry: newLogger(o.l, o).WithFields(logrus.Fields{
 			"audience": "application", "service_name": name, "service_version": version}),
 	}
@@ -215,7 +215,7 @@ func NewAudit(name string, version string, opts ...Option) *Logger {
 
 func (l *Logger) UseConfig(c configurator) {
 	l.leakSensitive = l.leakSensitive || c.Bool("log.leak_sensitive_values")
-	l.redactionText = stringsx.DefaultIfEmpty(c.String("log.redaction_text"), l.redactionText)
+	l.redactionText = stringsx.Coalesce(c.String("log.redaction_text"), l.redactionText)
 	o := newOptions(append(l.opts, WithConfigurator(c)))
 	setLevel(l.Entry.Logger, o)
 	setFormatter(l.Entry.Logger, o)
diff --git a/stringslice/filter.go b/stringslice/filter.go
index cdefd02e..2ebbee64 100644
--- a/stringslice/filter.go
+++ b/stringslice/filter.go
@@ -4,27 +4,19 @@
 package stringslice
 
 import (
+	"slices"
 	"strings"
 	"unicode"
 )
 
 // Filter applies the provided filter function and removes all items from the slice for which the filter function returns true.
-// This function uses append and might cause
-func Filter(values []string, filter func(string) bool) (ret []string) {
-	for _, value := range values {
-		if !filter(value) {
-			ret = append(ret, value)
-		}
-	}
-
-	if ret == nil {
-		return []string{}
-	}
-
-	return
+// Deprecated: use slices.DeleteFunc instead (changes semantics: the original slice is modified)
+func Filter(values []string, filter func(string) bool) []string {
+	return slices.DeleteFunc(slices.Clone(values), filter)
 }
 
 // TrimEmptyFilter applies the strings.TrimFunc function and removes all empty strings
+// Deprecated: use slices.DeleteFunc instead (changes semantics: the original slice is modified)
 func TrimEmptyFilter(values []string, trim func(rune) bool) (ret []string) {
 	return Filter(values, func(value string) bool {
 		return strings.TrimFunc(value, trim) == ""
@@ -32,6 +24,7 @@ func TrimEmptyFilter(values []string, trim func(rune) bool) (ret []string) {
 }
 
 // TrimSpaceEmptyFilter applies the strings.TrimSpace function and removes all empty strings
+// Deprecated: use slices.DeleteFunc with strings.TrimSpace instead (changes semantics: the original slice is modified)
 func TrimSpaceEmptyFilter(values []string) []string {
 	return TrimEmptyFilter(values, unicode.IsSpace)
 }
diff --git a/stringslice/has.go b/stringslice/has.go
index b75a6e6b..e863fa84 100644
--- a/stringslice/has.go
+++ b/stringslice/has.go
@@ -3,24 +3,20 @@
 
 package stringslice
 
-import "strings"
+import (
+	"slices"
+	"strings"
+)
 
 // Has returns true if the needle is in the haystack (case-sensitive)
+// Deprecated: use slices.Contains instead
 func Has(haystack []string, needle string) bool {
-	for _, current := range haystack {
-		if current == needle {
-			return true
-		}
-	}
-	return false
+	return slices.Contains(haystack, needle)
 }
 
 // HasI returns true if the needle is in the haystack (case-insensitive)
 func HasI(haystack []string, needle string) bool {
-	for _, current := range haystack {
-		if strings.EqualFold(current, needle) {
-			return true
-		}
-	}
-	return false
+	return slices.ContainsFunc(haystack, func(value string) bool {
+		return strings.EqualFold(value, needle)
+	})
 }
diff --git a/stringslice/merge.go b/stringslice/merge.go
index 92438732..fe0c887b 100644
--- a/stringslice/merge.go
+++ b/stringslice/merge.go
@@ -3,12 +3,10 @@
 
 package stringslice
 
+import "slices"
+
 // Merge merges several string slices into one.
+// Deprecated: use slices.Concat instead
 func Merge(parts ...[]string) []string {
-	var result []string
-	for _, part := range parts {
-		result = append(result, part...)
-	}
-
-	return result
+	return slices.Concat(parts...)
 }
diff --git a/stringslice/reverse.go b/stringslice/reverse.go
index 054fc21f..ca205500 100644
--- a/stringslice/reverse.go
+++ b/stringslice/reverse.go
@@ -3,12 +3,12 @@
 
 package stringslice
 
-func Reverse(s []string) []string {
-	r := make([]string, len(s))
-
-	for i, j := 0, len(r)-1; i <= j; i, j = i+1, j-1 {
-		r[i], r[j] = s[j], s[i]
-	}
+import "slices"
 
-	return r
+// Reverse reverses the order of a string slice
+// Deprecated: use slices.Reverse instead (changes semantics)
+func Reverse(s []string) []string {
+	c := slices.Clone(s)
+	slices.Reverse(c)
+	return c
 }
diff --git a/stringslice/unique.go b/stringslice/unique.go
index 6228c5e4..7a649d45 100644
--- a/stringslice/unique.go
+++ b/stringslice/unique.go
@@ -3,14 +3,15 @@
 
 package stringslice
 
-// Unique returns the given string slice with unique values.
+// Unique returns the given string slice with unique values, preserving order.
+// Consider using slices.Compact with slices.Sort instead when you don't care about order.
 func Unique(i []string) []string {
 	u := make([]string, 0, len(i))
-	m := make(map[string]bool)
+	m := make(map[string]struct{}, len(i))
 
 	for _, val := range i {
 		if _, ok := m[val]; !ok {
-			m[val] = true
+			m[val] = struct{}{}
 			u = append(u, val)
 		}
 	}
diff --git a/stringsx/default.go b/stringsx/default.go
index 0ae2769b..e494b22d 100644
--- a/stringsx/default.go
+++ b/stringsx/default.go
@@ -3,9 +3,7 @@
 
 package stringsx
 
+// Deprecated: use Coalesce instead
 func DefaultIfEmpty(s string, defaultValue string) string {
-	if len(s) == 0 {
-		return defaultValue
-	}
-	return s
+	return Coalesce(s, defaultValue)
 }
diff --git a/stringsx/ptr.go b/stringsx/ptr.go
index 0a94acbf..990aa3f8 100644
--- a/stringsx/ptr.go
+++ b/stringsx/ptr.go
@@ -3,6 +3,7 @@
 
 package stringsx
 
+// Deprecated: use pointerx.Ptr instead
 func GetPointer(s string) *string {
 	return &s
 }
diff --git a/stringsx/switch_case.go b/stringsx/switch_case.go
index 9e8f1101..dc5cb7fe 100644
--- a/stringsx/switch_case.go
+++ b/stringsx/switch_case.go
@@ -5,6 +5,7 @@ package stringsx
 
 import (
 	"fmt"
+	"slices"
 	"strings"
 )
 
@@ -42,14 +43,16 @@ func SwitchPrefix(actual string) *RegisteredPrefixes {
 	}
 }
 
-func (r *RegisteredCases) AddCase(c string) bool {
-	r.cases = append(r.cases, c)
-	return r.actual == c
+func (r *RegisteredCases) AddCase(cases ...string) bool {
+	r.cases = append(r.cases, cases...)
+	return slices.Contains(cases, r.actual)
 }
 
-func (r *RegisteredPrefixes) HasPrefix(prefix string) bool {
-	r.prefixes = append(r.prefixes, prefix)
-	return strings.HasPrefix(r.actual, prefix)
+func (r *RegisteredPrefixes) HasPrefix(prefixes ...string) bool {
+	r.prefixes = append(r.prefixes, prefixes...)
+	return slices.ContainsFunc(prefixes, func(s string) bool {
+		return strings.HasPrefix(r.actual, s)
+	})
 }
 
 func (r *RegisteredCases) String() string {