diff --git a/form/form_custom_type_decoder.go b/form/form_custom_type_decoder.go
new file mode 100644
index 0000000..bf6d0c2
--- /dev/null
+++ b/form/form_custom_type_decoder.go
@@ -0,0 +1,129 @@
+package form
+
+import (
+	"strconv"
+	"strings"
+
+	"github.com/go-playground/form/v4"
+	"golang.org/x/exp/constraints"
+)
+
+func RegisterBuiltinSliceTypeDecoderComma(dec *form.Decoder) {
+	dec.RegisterCustomTypeFunc(DecodeCustomIntSlice[int], []int{})
+	dec.RegisterCustomTypeFunc(DecodeCustomInt8Slice[int8], []int8{})
+	dec.RegisterCustomTypeFunc(DecodeCustomInt16Slice[int16], []int16{})
+	dec.RegisterCustomTypeFunc(DecodeCustomInt32Slice[int32], []int32{})
+	dec.RegisterCustomTypeFunc(DecodeCustomInt64Slice[int64], []int64{})
+	dec.RegisterCustomTypeFunc(DecodeCustomUintSlice[uint], []uint{})
+	dec.RegisterCustomTypeFunc(DecodeCustomUint8Slice[uint8], []uint8{})
+	dec.RegisterCustomTypeFunc(DecodeCustomUint16Slice[uint16], []uint16{})
+	dec.RegisterCustomTypeFunc(DecodeCustomUint32Slice[uint32], []uint32{})
+	dec.RegisterCustomTypeFunc(DecodeCustomUint64Slice[uint64], []uint64{})
+	dec.RegisterCustomTypeFunc(DecodeCustomFloat32Slice[float32], []float32{})
+	dec.RegisterCustomTypeFunc(DecodeCustomFloat64Slice[float64], []float64{})
+	dec.RegisterCustomTypeFunc(DecodeCustomStringSlice[string], []string{})
+}
+
+//* encoder: custom type number/string slice/array
+
+func DecodeCustomUintSlice[T ~uint](values []string) (any, error) {
+	return decodeNumber[T](values, func(s string) (uint64, error) {
+		return strconv.ParseUint(s, 10, 0)
+	})
+}
+
+func DecodeCustomUint8Slice[T ~uint8](values []string) (any, error) {
+	return decodeNumber[T](values, func(s string) (uint64, error) {
+		return strconv.ParseUint(s, 10, 8)
+	})
+}
+
+func DecodeCustomUint16Slice[T ~uint16](values []string) (any, error) {
+	return decodeNumber[T](values, func(s string) (uint64, error) {
+		return strconv.ParseUint(s, 10, 16)
+	})
+}
+
+func DecodeCustomUint32Slice[T ~uint32](values []string) (any, error) {
+	return decodeNumber[T](values, func(s string) (uint64, error) {
+		return strconv.ParseUint(s, 10, 32)
+	})
+}
+
+func DecodeCustomUint64Slice[T ~uint64](values []string) (any, error) {
+	return decodeNumber[T](values, func(s string) (uint64, error) {
+		return strconv.ParseUint(s, 10, 64)
+	})
+}
+
+func DecodeCustomIntSlice[T ~int](values []string) (any, error) {
+	return decodeNumber[T](values, func(s string) (int64, error) {
+		return strconv.ParseInt(s, 10, 0)
+	})
+}
+
+func DecodeCustomInt8Slice[T ~int8](values []string) (any, error) {
+	return decodeNumber[T](values, func(s string) (int64, error) {
+		return strconv.ParseInt(s, 10, 8)
+	})
+}
+
+func DecodeCustomInt16Slice[T ~int16](values []string) (any, error) {
+	return decodeNumber[T](values, func(s string) (int64, error) {
+		return strconv.ParseInt(s, 10, 16)
+	})
+}
+
+func DecodeCustomInt32Slice[T ~int32](values []string) (any, error) {
+	return decodeNumber[T](values, func(s string) (int64, error) {
+		return strconv.ParseInt(s, 10, 32)
+	})
+}
+
+func DecodeCustomInt64Slice[T ~int64](values []string) (any, error) {
+	return decodeNumber[T](values, func(s string) (int64, error) {
+		return strconv.ParseInt(s, 10, 64)
+	})
+}
+
+func DecodeCustomFloat64Slice[T ~float64](values []string) (any, error) {
+	return decodeNumber[T](values, func(s string) (float64, error) {
+		return strconv.ParseFloat(s, 64)
+	})
+}
+
+func DecodeCustomFloat32Slice[T ~float32](values []string) (any, error) {
+	return decodeNumber[T](values, func(s string) (float64, error) {
+		return strconv.ParseFloat(s, 32)
+	})
+}
+
+func DecodeCustomStringSlice[T ~string](values []string) (any, error) {
+	if len(values) == 0 {
+		return []T{}, nil
+	}
+	ret := make([]T, 0, 32)
+	for _, s := range values {
+		for _, v := range strings.Split(s, ",") {
+			ret = append(ret, T(v))
+		}
+	}
+	return ret, nil
+}
+
+func decodeNumber[T constraints.Integer | constraints.Float, V ~uint64 | ~int64 | ~float64](values []string, parse func(string) (V, error)) (any, error) {
+	if len(values) == 0 {
+		return []T{}, nil
+	}
+	ret := make([]T, 0, 32)
+	for _, s := range values {
+		for _, v := range strings.Split(s, ",") {
+			i, err := parse(v)
+			if err != nil {
+				return nil, err
+			}
+			ret = append(ret, T(i))
+		}
+	}
+	return ret, nil
+}
diff --git a/form/form_custom_type_decoder_test.go b/form/form_custom_type_decoder_test.go
new file mode 100644
index 0000000..875d38b
--- /dev/null
+++ b/form/form_custom_type_decoder_test.go
@@ -0,0 +1,103 @@
+package form
+
+import (
+	"net/url"
+	"testing"
+
+	"github.com/go-playground/form/v4"
+	"github.com/stretchr/testify/require"
+)
+
+type CustomInt int
+type CustomInt8 int8
+type CustomInt16 int16
+type CustomInt32 int32
+type CustomInt64 int64
+type CustomUint uint
+type CustomUint8 uint8
+type CustomUint16 uint16
+type CustomUint32 uint32
+type CustomUint64 uint64
+type CustomFloat32 float32
+type CustomFloat64 float64
+type CustomString string
+
+type customDecode struct {
+	I    []int           `json:"i"`
+	I8   []int8          `json:"i8"`
+	I16  []int16         `json:"i16"`
+	I32  []int32         `json:"i32"`
+	I64  []int64         `json:"i64"`
+	U    []int           `json:"u"`
+	U8   []int8          `json:"u8"`
+	U16  []int16         `json:"u16"`
+	U32  []int32         `json:"u32"`
+	U64  []int64         `json:"u64"`
+	F32  []float32       `json:"f32"`
+	F64  []float64       `json:"f64"`
+	S    []string        `json:"s"`
+	Ci   []CustomInt     `json:"ci"`
+	Ci8  []CustomInt8    `json:"ci8"`
+	Ci16 []CustomInt16   `json:"ci16"`
+	Ci32 []CustomInt32   `json:"ci32"`
+	Ci64 []CustomInt64   `json:"ci64"`
+	Cu   []CustomUint    `json:"cu"`
+	Cu8  []CustomUint8   `json:"cu8"`
+	Cu16 []CustomUint16  `json:"cu16"`
+	Cu32 []CustomUint32  `json:"cu32"`
+	Cu64 []CustomUint64  `json:"cu64"`
+	Cf32 []CustomFloat32 `json:"cf32"`
+	Cf64 []CustomFloat64 `json:"cf64"`
+	Cs   []CustomString  `json:"cs"`
+}
+
+func Test_CustomTypeDecoder(t *testing.T) {
+	dec := form.NewDecoder()
+	dec.SetTagName("json")
+
+	RegisterBuiltinSliceTypeDecoderComma(dec)
+	dec.RegisterCustomTypeFunc(DecodeCustomIntSlice[CustomInt], []CustomInt{})
+	dec.RegisterCustomTypeFunc(DecodeCustomInt8Slice[CustomInt8], []CustomInt8{})
+	dec.RegisterCustomTypeFunc(DecodeCustomInt16Slice[CustomInt16], []CustomInt16{})
+	dec.RegisterCustomTypeFunc(DecodeCustomInt32Slice[CustomInt32], []CustomInt32{})
+	dec.RegisterCustomTypeFunc(DecodeCustomInt64Slice[CustomInt64], []CustomInt64{})
+	dec.RegisterCustomTypeFunc(DecodeCustomUintSlice[CustomUint], []CustomUint{})
+	dec.RegisterCustomTypeFunc(DecodeCustomUint8Slice[CustomUint8], []CustomUint8{})
+	dec.RegisterCustomTypeFunc(DecodeCustomUint16Slice[CustomUint16], []CustomUint16{})
+	dec.RegisterCustomTypeFunc(DecodeCustomUint32Slice[CustomUint32], []CustomUint32{})
+	dec.RegisterCustomTypeFunc(DecodeCustomUint64Slice[CustomUint64], []CustomUint64{})
+	dec.RegisterCustomTypeFunc(DecodeCustomFloat32Slice[CustomFloat32], []CustomFloat32{})
+	dec.RegisterCustomTypeFunc(DecodeCustomFloat64Slice[CustomFloat64], []CustomFloat64{})
+	dec.RegisterCustomTypeFunc(DecodeCustomStringSlice[CustomString], []CustomString{})
+	got := customDecode{}
+	err := dec.Decode(&got, url.Values{
+		"i":    []string{"1,2,3", "4,5,6"},
+		"i8":   []string{"81,82,83"},
+		"i16":  []string{"161,162,163"},
+		"i32":  []string{"321,322,323"},
+		"i64":  []string{"641,642,643"},
+		"u":    []string{"111111,222222,333333"},
+		"u8":   []string{"11,22,33"},
+		"u16":  []string{"1611,1622,1633"},
+		"u32":  []string{"3211,3222,3233"},
+		"u64":  []string{"6411,6422,6433"},
+		"f32":  []string{"1.1,1.2,1.3"},
+		"f64":  []string{"2.1,2.2,2.3"},
+		"s":    []string{"a,b,c", "d,e,f"},
+		"ci":   []string{"1,2,3"},
+		"ci8":  []string{"81,82,83"},
+		"ci16": []string{"161,162,163"},
+		"ci32": []string{"321,322,323"},
+		"ci64": []string{"641,642,643"},
+		"cu":   []string{"111111,222222,333333"},
+		"cu8":  []string{"11,22,33"},
+		"cu16": []string{"1611,1622,1633"},
+		"cu32": []string{"3211,3222,3233"},
+		"cu64": []string{"6411,6422,6433"},
+		"cf32": []string{"1.1,1.2,1.3"},
+		"cf64": []string{"2.1,2.2,2.3"},
+		"cs":   []string{"a,b,c"},
+	})
+	require.NoError(t, err)
+	t.Logf("%#v", got)
+}
diff --git a/form/form_custom_type_encoder.go b/form/form_custom_type_encoder.go
new file mode 100644
index 0000000..92aa28b
--- /dev/null
+++ b/form/form_custom_type_encoder.go
@@ -0,0 +1,76 @@
+package form
+
+import (
+	"fmt"
+	"strconv"
+	"strings"
+
+	"golang.org/x/exp/constraints"
+)
+
+//* encoder: custom type number/string slice/array
+
+func EncodeCustomUnsignedIntegerSlice[T constraints.Unsigned](x any) ([]string, error) {
+	return encodeCustomNumberSlice[T](x, func(u uint64) string {
+		return strconv.FormatUint(u, 10)
+	})
+}
+
+func EncodeCustomSignedIntegerSlice[T constraints.Unsigned](x any) ([]string, error) {
+	return encodeCustomNumberSlice[T](x, func(u int64) string {
+		return strconv.FormatInt(u, 10)
+	})
+}
+
+func EncodeCustomFloat32Slice[T ~float32](x any) ([]string, error) {
+	return encodeCustomNumberSlice[T](x, func(u float64) string {
+		return strconv.FormatFloat(u, 'f', -1, 32)
+	})
+}
+
+func EncodeCustomFloat64Slice[T ~float64](x any) ([]string, error) {
+	return encodeCustomNumberSlice[T](x, func(u float64) string {
+		return strconv.FormatFloat(u, 'f', -1, 64)
+	})
+}
+
+func EncodeCustomStringSlice[T ~string](x any) ([]string, error) {
+	vs, ok := x.([]T)
+	if !ok {
+		return nil, fmt.Errorf("")
+	}
+	has := false
+	b := strings.Builder{}
+	for _, vv := range vs {
+		if vv == "" {
+			continue
+		}
+		if has {
+			b.WriteString(",")
+		}
+		has = true
+		b.WriteString(string(vv))
+	}
+	return []string{b.String()}, nil
+}
+
+func encodeCustomNumberSlice[T constraints.Integer | constraints.Float, V uint64 | int64 | float64](x any, format func(V) string) ([]string, error) {
+	vs, ok := x.([]T)
+	if !ok {
+		return nil, fmt.Errorf("")
+	}
+	has := false
+	b := strings.Builder{}
+	for _, v := range vs {
+		vv := format(V(v))
+		if vv == "" {
+			continue
+		}
+		if has {
+			b.WriteString(",")
+		}
+		has = true
+		b.WriteString(vv)
+	}
+	return []string{b.String()}, nil
+}
diff --git a/form/form_custom_type_encoder_test.go b/form/form_custom_type_encoder_test.go
new file mode 100644
index 0000000..b50f6a4
--- /dev/null
+++ b/form/form_custom_type_encoder_test.go
@@ -0,0 +1 @@
+package form
diff --git a/go.mod b/go.mod
index 8ab51e1..1070134 100644
--- a/go.mod
+++ b/go.mod
@@ -9,6 +9,7 @@ require (
 	github.com/spf13/cast v1.6.0
 	github.com/stretchr/testify v1.9.0
 	github.com/ugorji/go/codec v1.2.12
+	golang.org/x/exp v0.0.0-20240525044651-4c93da0ed11d
 	google.golang.org/genproto/googleapis/api v0.0.0-20240415180920-8c6c420018be
 	google.golang.org/protobuf v1.34.1
 	gopkg.in/yaml.v3 v3.0.1
diff --git a/go.sum b/go.sum
index 9ca39c0..d82f4df 100644
--- a/go.sum
+++ b/go.sum
@@ -32,6 +32,8 @@ github.com/stretchr/testify v1.9.0 h1:HtqpIVDClZ4nwg75+f6Lvsy/wHu+3BoSGCbBAcpTsT
 github.com/stretchr/testify v1.9.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=
 github.com/ugorji/go/codec v1.2.12 h1:9LC83zGrHhuUA9l16C9AHXAqEV/2wBQ4nkvumAE65EE=
 github.com/ugorji/go/codec v1.2.12/go.mod h1:UNopzCgEMSXjBc6AOMqYvWC1ktqTAfzJZUZgYf6w6lg=
+golang.org/x/exp v0.0.0-20240525044651-4c93da0ed11d h1:N0hmiNbwsSNwHBAvR3QB5w25pUwH4tK0Y/RltD1j1h4=
+golang.org/x/exp v0.0.0-20240525044651-4c93da0ed11d/go.mod h1:XtvwrStGgqGPLc4cjQfWqZHG1YFdYs6swckp8vpsjnc=
 google.golang.org/genproto/googleapis/api v0.0.0-20240415180920-8c6c420018be h1:Zz7rLWqp0ApfsR/l7+zSHhY3PMiH2xqgxlfYfAfNpoU=
 google.golang.org/genproto/googleapis/api v0.0.0-20240415180920-8c6c420018be/go.mod h1:dvdCTIoAGbkWbcIKBniID56/7XHTt6WfxXNMxuziJ+w=
 google.golang.org/protobuf v1.34.1 h1:9ddQBjfCyZPOHPUiPxpYESBLc+T8P3E+Vo4IbKZgFWg=