diff --git a/cm/list.go b/cm/list.go
index 5c896d04..c73ec97b 100644
--- a/cm/list.go
+++ b/cm/list.go
@@ -1,6 +1,9 @@
 package cm
 
-import "unsafe"
+import (
+	"encoding/json"
+	"unsafe"
+)
 
 // List represents a Component Model list.
 // The binary representation of list<T> is similar to a Go slice minus the cap field.
@@ -9,6 +12,20 @@ type List[T any] struct {
 	list[T]
 }
 
+func (l List[T]) MarshalJSON() ([]byte, error) {
+	return json.Marshal(l.Slice())
+}
+
+func (l *List[T]) UnmarshalJSON(buf []byte) error {
+	var data []T
+	err := json.Unmarshal(buf, &data)
+	if err != nil {
+		return err
+	}
+	*l = ToList(data)
+	return nil
+}
+
 // AnyList is a type constraint for generic functions that accept any [List] type.
 type AnyList[T any] interface {
 	~struct {
diff --git a/cm/option.go b/cm/option.go
index cf7024aa..9cba967f 100644
--- a/cm/option.go
+++ b/cm/option.go
@@ -1,5 +1,9 @@
 package cm
 
+import (
+	"encoding/json"
+)
+
 // Option represents a Component Model [option<T>] type.
 //
 // [option<T>]: https://component-model.bytecodealliance.org/design/wit.html#options
@@ -8,6 +12,27 @@ type Option[T any] struct {
 	option[T]
 }
 
+// MarshalJSON implements the json.Marshaler interface for [Option].
+func (o Option[T]) MarshalJSON() ([]byte, error) {
+	return json.Marshal(o.Some())
+}
+
+// UnmarshalJSON unmarshals the Option from JSON.
+func (o *Option[T]) UnmarshalJSON(buf []byte) error {
+	if len(buf) == 0 {
+		*o = None[T]()
+		return nil
+	}
+
+	var v T
+	if err := json.Unmarshal(buf, &v); err != nil {
+		return err
+	}
+
+	*o = Some(v)
+	return nil
+}
+
 // None returns an [Option] representing the none case,
 // equivalent to the zero value.
 func None[T any]() Option[T] {
diff --git a/cm/tuple.go b/cm/tuple.go
index 610a19be..a1ec0382 100644
--- a/cm/tuple.go
+++ b/cm/tuple.go
@@ -1,5 +1,13 @@
 package cm
 
+import (
+	"encoding/json"
+	"errors"
+)
+
+// ErrInvalidTuple is returned when a Tuple fails to unmarshal from JSON.
+var ErrInvalidTuple = errors.New("invalid tuple")
+
 // Tuple represents a [Component Model tuple] with 2 fields.
 //
 // [Component Model tuple]: https://component-model.bytecodealliance.org/design/wit.html#tuples
@@ -9,6 +17,30 @@ type Tuple[T0, T1 any] struct {
 	F1 T1
 }
 
+// MarshalJSON marshals the Tuple into JSON.
+func (t Tuple[T0, T1]) MarshalJSON() ([]byte, error) {
+	l := []any{t.F0, t.F1}
+	return json.Marshal(l)
+}
+
+// UnmarshalJSON unmarshals the Tuple from JSON.
+func (t *Tuple[T0, T1]) UnmarshalJSON(buf []byte) error {
+	tmp := []json.RawMessage{}
+	if err := json.Unmarshal(buf, &tmp); err != nil {
+		return err
+	}
+	if len(tmp) != 2 {
+		return ErrInvalidTuple
+	}
+	if err := json.Unmarshal(tmp[0], &t.F0); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[1], &t.F1); err != nil {
+		return err
+	}
+	return nil
+}
+
 // Tuple3 represents a [Component Model tuple] with 3 fields.
 //
 // [Component Model tuple]: https://component-model.bytecodealliance.org/design/wit.html#tuples
@@ -19,6 +51,32 @@ type Tuple3[T0, T1, T2 any] struct {
 	F2 T2
 }
 
+func (t Tuple3[T0, T1, T2]) MarshalJSON() ([]byte, error) {
+	l := []any{t.F0, t.F1, t.F2}
+	return json.Marshal(l)
+}
+
+// UnmarshalJSON unmarshals the Tuple from JSON.
+func (t *Tuple3[T0, T1, T2]) UnmarshalJSON(buf []byte) error {
+	tmp := []json.RawMessage{}
+	if err := json.Unmarshal(buf, &tmp); err != nil {
+		return err
+	}
+	if len(tmp) != 3 {
+		return ErrInvalidTuple
+	}
+	if err := json.Unmarshal(tmp[0], &t.F0); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[1], &t.F1); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[2], &t.F2); err != nil {
+		return err
+	}
+	return nil
+}
+
 // Tuple4 represents a [Component Model tuple] with 4 fields.
 //
 // [Component Model tuple]: https://component-model.bytecodealliance.org/design/wit.html#tuples
@@ -30,6 +88,36 @@ type Tuple4[T0, T1, T2, T3 any] struct {
 	F3 T3
 }
 
+// MarshalJSON marshals the Tuple into JSON.
+func (t Tuple4[T0, T1, T2, T3]) MarshalJSON() ([]byte, error) {
+	l := []any{t.F0, t.F1, t.F2, t.F3}
+	return json.Marshal(l)
+}
+
+// UnmarshalJSON unmarshals the Tuple from JSON.
+func (t *Tuple4[T0, T1, T2, T3]) UnmarshalJSON(buf []byte) error {
+	tmp := []json.RawMessage{}
+	if err := json.Unmarshal(buf, &tmp); err != nil {
+		return err
+	}
+	if len(tmp) != 4 {
+		return ErrInvalidTuple
+	}
+	if err := json.Unmarshal(tmp[0], &t.F0); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[1], &t.F1); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[2], &t.F2); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[3], &t.F3); err != nil {
+		return err
+	}
+	return nil
+}
+
 // Tuple5 represents a [Component Model tuple] with 5 fields.
 //
 // [Component Model tuple]: https://component-model.bytecodealliance.org/design/wit.html#tuples
@@ -42,6 +130,39 @@ type Tuple5[T0, T1, T2, T3, T4 any] struct {
 	F4 T4
 }
 
+// MarshalJSON marshals the Tuple into JSON.
+func (t Tuple5[T0, T1, T2, T3, T4]) MarshalJSON() ([]byte, error) {
+	l := []any{t.F0, t.F1, t.F2, t.F3, t.F4}
+	return json.Marshal(l)
+}
+
+// UnmarshalJSON unmarshals the Tuple from JSON.
+func (t *Tuple5[T0, T1, T2, T3, T4]) UnmarshalJSON(buf []byte) error {
+	tmp := []json.RawMessage{}
+	if err := json.Unmarshal(buf, &tmp); err != nil {
+		return err
+	}
+	if len(tmp) != 5 {
+		return ErrInvalidTuple
+	}
+	if err := json.Unmarshal(tmp[0], &t.F0); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[1], &t.F1); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[2], &t.F2); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[3], &t.F3); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[4], &t.F4); err != nil {
+		return err
+	}
+	return nil
+}
+
 // Tuple6 represents a [Component Model tuple] with 6 fields.
 //
 // [Component Model tuple]: https://component-model.bytecodealliance.org/design/wit.html#tuples
@@ -55,6 +176,42 @@ type Tuple6[T0, T1, T2, T3, T4, T5 any] struct {
 	F5 T5
 }
 
+// MarshalJSON marshals the Tuple into JSON.
+func (t Tuple6[T0, T1, T2, T3, T4, T5]) MarshalJSON() ([]byte, error) {
+	l := []any{t.F0, t.F1, t.F2, t.F3, t.F4, t.F5}
+	return json.Marshal(l)
+}
+
+// UnmarshalJSON unmarshals the Tuple from JSON.
+func (t *Tuple6[T0, T1, T2, T3, T4, T5]) UnmarshalJSON(buf []byte) error {
+	tmp := []json.RawMessage{}
+	if err := json.Unmarshal(buf, &tmp); err != nil {
+		return err
+	}
+	if len(tmp) != 6 {
+		return ErrInvalidTuple
+	}
+	if err := json.Unmarshal(tmp[0], &t.F0); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[1], &t.F1); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[2], &t.F2); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[3], &t.F3); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[4], &t.F4); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[5], &t.F5); err != nil {
+		return err
+	}
+	return nil
+}
+
 // Tuple7 represents a [Component Model tuple] with 7 fields.
 //
 // [Component Model tuple]: https://component-model.bytecodealliance.org/design/wit.html#tuples
@@ -69,6 +226,45 @@ type Tuple7[T0, T1, T2, T3, T4, T5, T6 any] struct {
 	F6 T6
 }
 
+// MarshalJSON marshals the Tuple into JSON.
+func (t Tuple7[T0, T1, T2, T3, T4, T5, T6]) MarshalJSON() ([]byte, error) {
+	l := []any{t.F0, t.F1, t.F2, t.F3, t.F4, t.F5, t.F6}
+	return json.Marshal(l)
+}
+
+// UnmarshalJSON unmarshals the Tuple from JSON.
+func (t *Tuple7[T0, T1, T2, T3, T4, T5, T6]) UnmarshalJSON(buf []byte) error {
+	tmp := []json.RawMessage{}
+	if err := json.Unmarshal(buf, &tmp); err != nil {
+		return err
+	}
+	if len(tmp) != 7 {
+		return ErrInvalidTuple
+	}
+	if err := json.Unmarshal(tmp[0], &t.F0); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[1], &t.F1); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[2], &t.F2); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[3], &t.F3); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[4], &t.F4); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[5], &t.F5); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[6], &t.F6); err != nil {
+		return err
+	}
+	return nil
+}
+
 // Tuple8 represents a [Component Model tuple] with 8 fields.
 //
 // [Component Model tuple]: https://component-model.bytecodealliance.org/design/wit.html#tuples
@@ -84,6 +280,48 @@ type Tuple8[T0, T1, T2, T3, T4, T5, T6, T7 any] struct {
 	F7 T7
 }
 
+// MarshalJSON marshals the Tuple into JSON.
+func (t Tuple8[T0, T1, T2, T3, T4, T5, T6, T7]) MarshalJSON() ([]byte, error) {
+	l := []any{t.F0, t.F1, t.F2, t.F3, t.F4, t.F5, t.F6, t.F7}
+	return json.Marshal(l)
+}
+
+// UnmarshalJSON unmarshals the Tuple from JSON.
+func (t *Tuple8[T0, T1, T2, T3, T4, T5, T6, T7]) UnmarshalJSON(buf []byte) error {
+	tmp := []json.RawMessage{}
+	if err := json.Unmarshal(buf, &tmp); err != nil {
+		return err
+	}
+	if len(tmp) != 8 {
+		return ErrInvalidTuple
+	}
+	if err := json.Unmarshal(tmp[0], &t.F0); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[1], &t.F1); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[2], &t.F2); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[3], &t.F3); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[4], &t.F4); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[5], &t.F5); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[6], &t.F6); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[7], &t.F7); err != nil {
+		return err
+	}
+	return nil
+}
+
 // Tuple9 represents a [Component Model tuple] with 9 fields.
 //
 // [Component Model tuple]: https://component-model.bytecodealliance.org/design/wit.html#tuples
@@ -100,6 +338,51 @@ type Tuple9[T0, T1, T2, T3, T4, T5, T6, T7, T8 any] struct {
 	F8 T8
 }
 
+// MarshalJSON marshals the Tuple into JSON.
+func (t Tuple9[T0, T1, T2, T3, T4, T5, T6, T7, T8]) MarshalJSON() ([]byte, error) {
+	l := []any{t.F0, t.F1, t.F2, t.F3, t.F4, t.F5, t.F6, t.F7, t.F8}
+	return json.Marshal(l)
+}
+
+// UnmarshalJSON unmarshals the Tuple from JSON.
+func (t *Tuple9[T0, T1, T2, T3, T4, T5, T6, T7, T8]) UnmarshalJSON(buf []byte) error {
+	tmp := []json.RawMessage{}
+	if err := json.Unmarshal(buf, &tmp); err != nil {
+		return err
+	}
+	if len(tmp) != 9 {
+		return ErrInvalidTuple
+	}
+	if err := json.Unmarshal(tmp[0], &t.F0); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[1], &t.F1); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[2], &t.F2); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[3], &t.F3); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[4], &t.F4); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[5], &t.F5); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[6], &t.F6); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[7], &t.F7); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[8], &t.F8); err != nil {
+		return err
+	}
+	return nil
+}
+
 // Tuple10 represents a [Component Model tuple] with 10 fields.
 //
 // [Component Model tuple]: https://component-model.bytecodealliance.org/design/wit.html#tuples
@@ -117,6 +400,54 @@ type Tuple10[T0, T1, T2, T3, T4, T5, T6, T7, T8, T9 any] struct {
 	F9 T9
 }
 
+// MarshalJSON marshals the Tuple into JSON.
+func (t Tuple10[T0, T1, T2, T3, T4, T5, T6, T7, T8, T9]) MarshalJSON() ([]byte, error) {
+	l := []any{t.F0, t.F1, t.F2, t.F3, t.F4, t.F5, t.F6, t.F7, t.F8, t.F9}
+	return json.Marshal(l)
+}
+
+// UnmarshalJSON unmarshals the Tuple from JSON.
+func (t *Tuple10[T0, T1, T2, T3, T4, T5, T6, T7, T8, T9]) UnmarshalJSON(buf []byte) error {
+	tmp := []json.RawMessage{}
+	if err := json.Unmarshal(buf, &tmp); err != nil {
+		return err
+	}
+	if len(tmp) != 10 {
+		return ErrInvalidTuple
+	}
+	if err := json.Unmarshal(tmp[0], &t.F0); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[1], &t.F1); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[2], &t.F2); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[3], &t.F3); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[4], &t.F4); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[5], &t.F5); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[6], &t.F6); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[7], &t.F7); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[8], &t.F8); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[9], &t.F9); err != nil {
+		return err
+	}
+	return nil
+}
+
 // Tuple11 represents a [Component Model tuple] with 11 fields.
 //
 // [Component Model tuple]: https://component-model.bytecodealliance.org/design/wit.html#tuples
@@ -135,6 +466,57 @@ type Tuple11[T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10 any] struct {
 	F10 T10
 }
 
+// MarshalJSON marshals the Tuple into JSON.
+func (t Tuple11[T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10]) MarshalJSON() ([]byte, error) {
+	l := []any{t.F0, t.F1, t.F2, t.F3, t.F4, t.F5, t.F6, t.F7, t.F8, t.F9, t.F10}
+	return json.Marshal(l)
+}
+
+// UnmarshalJSON unmarshals the Tuple from JSON.
+func (t *Tuple11[T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10]) UnmarshalJSON(buf []byte) error {
+	tmp := []json.RawMessage{}
+	if err := json.Unmarshal(buf, &tmp); err != nil {
+		return err
+	}
+	if len(tmp) != 11 {
+		return ErrInvalidTuple
+	}
+	if err := json.Unmarshal(tmp[0], &t.F0); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[1], &t.F1); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[2], &t.F2); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[3], &t.F3); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[4], &t.F4); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[5], &t.F5); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[6], &t.F6); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[7], &t.F7); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[8], &t.F8); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[9], &t.F9); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[10], &t.F10); err != nil {
+		return err
+	}
+	return nil
+}
+
 // Tuple12 represents a [Component Model tuple] with 12 fields.
 //
 // [Component Model tuple]: https://component-model.bytecodealliance.org/design/wit.html#tuples
@@ -154,6 +536,60 @@ type Tuple12[T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11 any] struct {
 	F11 T11
 }
 
+// MarshalJSON marshals the Tuple into JSON.
+func (t Tuple12[T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11]) MarshalJSON() ([]byte, error) {
+	l := []any{t.F0, t.F1, t.F2, t.F3, t.F4, t.F5, t.F6, t.F7, t.F8, t.F9, t.F10, t.F11}
+	return json.Marshal(l)
+}
+
+// UnmarshalJSON unmarshals the Tuple from JSON.
+func (t *Tuple12[T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11]) UnmarshalJSON(buf []byte) error {
+	tmp := []json.RawMessage{}
+	if err := json.Unmarshal(buf, &tmp); err != nil {
+		return err
+	}
+	if len(tmp) != 12 {
+		return ErrInvalidTuple
+	}
+	if err := json.Unmarshal(tmp[0], &t.F0); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[1], &t.F1); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[2], &t.F2); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[3], &t.F3); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[4], &t.F4); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[5], &t.F5); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[6], &t.F6); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[7], &t.F7); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[8], &t.F8); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[9], &t.F9); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[10], &t.F10); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[11], &t.F11); err != nil {
+		return err
+	}
+	return nil
+}
+
 // Tuple13 represents a [Component Model tuple] with 13 fields.
 //
 // [Component Model tuple]: https://component-model.bytecodealliance.org/design/wit.html#tuples
@@ -174,6 +610,63 @@ type Tuple13[T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12 any] struct {
 	F12 T12
 }
 
+// MarshalJSON marshals the Tuple into JSON.
+func (t Tuple13[T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12]) MarshalJSON() ([]byte, error) {
+	l := []any{t.F0, t.F1, t.F2, t.F3, t.F4, t.F5, t.F6, t.F7, t.F8, t.F9, t.F10, t.F11, t.F12}
+	return json.Marshal(l)
+}
+
+// UnmarshalJSON unmarshals the Tuple from JSON.
+func (t *Tuple13[T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12]) UnmarshalJSON(buf []byte) error {
+	tmp := []json.RawMessage{}
+	if err := json.Unmarshal(buf, &tmp); err != nil {
+		return err
+	}
+	if len(tmp) != 13 {
+		return ErrInvalidTuple
+	}
+	if err := json.Unmarshal(tmp[0], &t.F0); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[1], &t.F1); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[2], &t.F2); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[3], &t.F3); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[4], &t.F4); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[5], &t.F5); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[6], &t.F6); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[7], &t.F7); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[8], &t.F8); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[9], &t.F9); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[10], &t.F10); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[11], &t.F11); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[12], &t.F12); err != nil {
+		return err
+	}
+	return nil
+}
+
 // Tuple14 represents a [Component Model tuple] with 14 fields.
 //
 // [Component Model tuple]: https://component-model.bytecodealliance.org/design/wit.html#tuples
@@ -195,6 +688,66 @@ type Tuple14[T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13 any] str
 	F13 T13
 }
 
+// MarshalJSON marshals the Tuple into JSON.
+func (t Tuple14[T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13]) MarshalJSON() ([]byte, error) {
+	l := []any{t.F0, t.F1, t.F2, t.F3, t.F4, t.F5, t.F6, t.F7, t.F8, t.F9, t.F10, t.F11, t.F12, t.F13}
+	return json.Marshal(l)
+}
+
+// UnmarshalJSON unmarshals the Tuple from JSON.
+func (t *Tuple14[T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13]) UnmarshalJSON(buf []byte) error {
+	tmp := []json.RawMessage{}
+	if err := json.Unmarshal(buf, &tmp); err != nil {
+		return err
+	}
+	if len(tmp) != 14 {
+		return ErrInvalidTuple
+	}
+	if err := json.Unmarshal(tmp[0], &t.F0); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[1], &t.F1); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[2], &t.F2); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[3], &t.F3); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[4], &t.F4); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[5], &t.F5); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[6], &t.F6); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[7], &t.F7); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[8], &t.F8); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[9], &t.F9); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[10], &t.F10); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[11], &t.F11); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[12], &t.F12); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[13], &t.F13); err != nil {
+		return err
+	}
+	return nil
+}
+
 // Tuple15 represents a [Component Model tuple] with 15 fields.
 //
 // [Component Model tuple]: https://component-model.bytecodealliance.org/design/wit.html#tuples
@@ -217,6 +770,69 @@ type Tuple15[T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14 any
 	F14 T14
 }
 
+// MarshalJSON marshals the Tuple into JSON.
+func (t Tuple15[T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14]) MarshalJSON() ([]byte, error) {
+	l := []any{t.F0, t.F1, t.F2, t.F3, t.F4, t.F5, t.F6, t.F7, t.F8, t.F9, t.F10, t.F11, t.F12, t.F13, t.F14}
+	return json.Marshal(l)
+}
+
+// UnmarshalJSON unmarshals the Tuple from JSON.
+func (t *Tuple15[T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14]) UnmarshalJSON(buf []byte) error {
+	tmp := []json.RawMessage{}
+	if err := json.Unmarshal(buf, &tmp); err != nil {
+		return err
+	}
+	if len(tmp) != 15 {
+		return ErrInvalidTuple
+	}
+	if err := json.Unmarshal(tmp[0], &t.F0); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[1], &t.F1); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[2], &t.F2); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[3], &t.F3); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[4], &t.F4); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[5], &t.F5); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[6], &t.F6); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[7], &t.F7); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[8], &t.F8); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[9], &t.F9); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[10], &t.F10); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[11], &t.F11); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[12], &t.F12); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[13], &t.F13); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[14], &t.F14); err != nil {
+		return err
+	}
+	return nil
+}
+
 // Tuple16 represents a [Component Model tuple] with 16 fields.
 //
 // [Component Model tuple]: https://component-model.bytecodealliance.org/design/wit.html#tuples
@@ -240,6 +856,72 @@ type Tuple16[T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T1
 	F15 T15
 }
 
+// MarshalJSON marshals the Tuple into JSON.
+func (t Tuple16[T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T16]) MarshalJSON() ([]byte, error) {
+	l := []any{t.F0, t.F1, t.F2, t.F3, t.F4, t.F5, t.F6, t.F7, t.F8, t.F9, t.F10, t.F11, t.F12, t.F13, t.F14, t.F15}
+	return json.Marshal(l)
+}
+
+// UnmarshalJSON unmarshals the Tuple from JSON.
+func (t *Tuple16[T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15]) UnmarshalJSON(buf []byte) error {
+	tmp := []json.RawMessage{}
+	if err := json.Unmarshal(buf, &tmp); err != nil {
+		return err
+	}
+	if len(tmp) != 16 {
+		return ErrInvalidTuple
+	}
+	if err := json.Unmarshal(tmp[0], &t.F0); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[1], &t.F1); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[2], &t.F2); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[3], &t.F3); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[4], &t.F4); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[5], &t.F5); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[6], &t.F6); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[7], &t.F7); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[8], &t.F8); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[9], &t.F9); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[10], &t.F10); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[11], &t.F11); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[12], &t.F12); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[13], &t.F13); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[14], &t.F14); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(tmp[15], &t.F15); err != nil {
+		return err
+	}
+	return nil
+}
+
 // MaxTuple specifies the maximum number of fields in a Tuple* type, currently [Tuple16].
 // See https://github.com/WebAssembly/component-model/issues/373 for more information.
 const MaxTuple = 16
diff --git a/cm/variant.go b/cm/variant.go
index 24703641..3e2c8887 100644
--- a/cm/variant.go
+++ b/cm/variant.go
@@ -1,6 +1,8 @@
 package cm
 
-import "unsafe"
+import (
+	"unsafe"
+)
 
 // Discriminant is the set of types that can represent the tag or discriminator of a variant.
 // Use bool for 2-case variant types, result<T>, or option<T> types, uint8 where there are 256 or
diff --git a/wit/bindgen/generator.go b/wit/bindgen/generator.go
index a1c6c63e..7298ca77 100644
--- a/wit/bindgen/generator.go
+++ b/wit/bindgen/generator.go
@@ -679,13 +679,13 @@ func (g *generator) recordRep(file *gen.File, dir wit.Direction, r *wit.Record,
 	exported := len(goName) == 0 || token.IsExported(goName)
 	var b strings.Builder
 	b.WriteString("struct {\n")
-	stringio.Write(&b, "_ ", file.Import(g.opts.cmPackage), ".HostLayout")
+	stringio.Write(&b, "_ ", file.Import(g.opts.cmPackage), ".HostLayout", "`json:\"-\"`")
 	for i, f := range r.Fields {
 		if i == 0 || i > 0 && f.Docs.Contents != "" {
 			b.WriteRune('\n')
 		}
 		b.WriteString(formatDocComments(f.Docs.Contents, false))
-		stringio.Write(&b, fieldName(f.Name, exported), " ", g.typeRep(file, dir, f.Type), "\n")
+		stringio.Write(&b, fieldName(f.Name, exported), " ", g.typeRep(file, dir, f.Type), "`json:\"", f.Name, "\"`", "\n")
 	}
 	b.WriteRune('}')
 	return b.String()
@@ -823,10 +823,14 @@ func (g *generator) variantRep(file *gen.File, dir wit.Direction, t *wit.TypeDef
 
 	decl, _ := g.typeDecl(dir, t)
 	scope := decl.scope
-	scope.DeclareName("String") // For fmt.Stringer
+	scope.DeclareName("String")        // For fmt.Stringer
+	scope.DeclareName("MarshalJSON")   // For encoding/json.Marshaler
+	scope.DeclareName("UnmarshalJSON") // For encoding/json.Unmarshaler
 
 	// Emit type
 	var b strings.Builder
+	var jsonMarshalCases strings.Builder
+	var jsonUnmarshalCases strings.Builder
 	cm := file.Import(g.opts.cmPackage)
 	stringio.Write(&b, cm, ".Variant[", g.typeRep(file, dir, disc), ", ", typeShape, ", ", g.typeRep(file, dir, align), "]\n\n")
 
@@ -867,6 +871,20 @@ func (g *generator) variantRep(file *gen.File, dir wit.Direction, t *wit.TypeDef
 			stringio.Write(&b, "return ", cm, ".Case[", typeRep, "](self, ", caseNum, ")")
 			b.WriteString("}\n\n")
 		}
+
+		stringio.Write(&jsonMarshalCases, "case ", caseNum, ":\n")
+		stringio.Write(&jsonMarshalCases, "val = v.", caseName, "()\n")
+
+		stringio.Write(&jsonUnmarshalCases, "case \"", c.Name, "\":\n")
+		if c.Type != nil {
+			stringio.Write(&jsonUnmarshalCases, "var tmp ", typeRep, "\n")
+			stringio.Write(&jsonUnmarshalCases, "if err := json.Unmarshal(data, &tmp); err != nil {\n")
+			stringio.Write(&jsonUnmarshalCases, "return err\n")
+			stringio.Write(&jsonUnmarshalCases, "}\n")
+			stringio.Write(&jsonUnmarshalCases, "*v = ", constructorName, "(tmp)\n")
+		} else {
+			stringio.Write(&jsonUnmarshalCases, "*v = ", constructorName, "()\n")
+		}
 	}
 
 	stringsName := file.DeclareName("strings" + GoName(goName, true))
@@ -881,6 +899,39 @@ func (g *generator) variantRep(file *gen.File, dir wit.Direction, t *wit.TypeDef
 	stringio.Write(&b, "return ", stringsName, "[v.Tag()]\n")
 	b.WriteString("}\n\n")
 
+	file.Import("encoding/json")
+	b.WriteString(formatDocComments("MarshalJSON implements [json.Marshaler].", true))
+	stringio.Write(&b, "func (v ", goName, ") MarshalJSON() ([]byte, error) {\n")
+	stringio.Write(&b, "ret := make(map[string]any)\n")
+	stringio.Write(&b, "var val any\n")
+	stringio.Write(&b, "switch v.Tag() {\n")
+	stringio.Write(&b, jsonMarshalCases.String())
+	stringio.Write(&b, "}\n")
+	stringio.Write(&b, "ret[v.String()] = val\n")
+	stringio.Write(&b, "return json.Marshal(ret)\n")
+	b.WriteString("}\n\n")
+
+	b.WriteString(formatDocComments("UnmarshalJSON implements [json.Unmarshaler].", true))
+	stringio.Write(&b, "func (v *", goName, ") UnmarshalJSON(buf []byte) error {\n")
+	stringio.Write(&b, "tagger := make(map[string]json.RawMessage)\n")
+	stringio.Write(&b, "var tag string\n")
+	stringio.Write(&b, "var data json.RawMessage\n")
+	stringio.Write(&b, "if err := json.Unmarshal(buf, &tagger); err != nil {\n")
+	stringio.Write(&b, "return err\n")
+	stringio.Write(&b, "}\n")
+	stringio.Write(&b, "if len(tagger) != 1 {\n")
+	stringio.Write(&b, "return nil\n")
+	stringio.Write(&b, "}\n")
+	stringio.Write(&b, "for tag, data = range tagger {\n")
+	stringio.Write(&b, "break\n")
+	stringio.Write(&b, "}\n")
+
+	stringio.Write(&b, "switch tag {\n")
+	stringio.Write(&b, jsonUnmarshalCases.String())
+	stringio.Write(&b, "}\n")
+	stringio.Write(&b, "return nil\n")
+	b.WriteString("}\n\n")
+
 	return b.String()
 }