diff --git a/nullable_unmarshaljson.go b/nullable_unmarshaljson.go
new file mode 100644
index 0000000..6155e1e
--- /dev/null
+++ b/nullable_unmarshaljson.go
@@ -0,0 +1,38 @@
+package nul
+
+import (
+	"fmt"
+	"encoding/json"
+)
+
+var _ json.Unmarshaler = new(Nullable[bool])
+var _ json.Unmarshaler = new(Nullable[string])
+
+// UnmarshalJSON makes it so json.Unmarshaler is implemented.
+func (receiver *Nullable[T]) UnmarshalJSON(data []byte) error {
+	switch interface{}(receiver.value).(type) {
+	case bool, string:
+		// these are OK.
+	default:
+		return fmt.Errorf("cannot unmarshal into something of type %T from JSON because parameterized type is ‘%T’ rather than ‘bool’ or ‘string’", receiver, receiver.value)
+	}
+
+	if 4 == len(data) && 'n' == data[0] && 'u' == data[1] && 'l' == data[2] && 'l' == data[3] {
+		*receiver = Null[T]()
+		return nil
+
+	}
+
+	{
+		var dst T
+
+		err := json.Unmarshal(data, &dst)
+		if nil != err {
+			return err
+		}
+
+		*receiver = Something(dst)
+	}
+
+	return nil
+}
diff --git a/nullable_unmarshaljson_bool_test.go b/nullable_unmarshaljson_bool_test.go
new file mode 100644
index 0000000..9026795
--- /dev/null
+++ b/nullable_unmarshaljson_bool_test.go
@@ -0,0 +1,70 @@
+package nul_test
+
+import (
+	"testing"
+
+	"encoding/json"
+
+	"sourcecode.social/reiver/go-nul"
+)
+
+func TestNullable_UnmarshalJSON_bool(t *testing.T) {
+
+	tests := []struct{
+		JSON string
+		Expected nul.Nullable[bool]
+	}{
+		{
+			JSON: `null`,
+			Expected: nul.Null[bool](),
+		},
+		{
+			JSON: `false`,
+			Expected: nul.Something(false),
+		},
+		{
+			JSON: `true`,
+			Expected: nul.Something(true),
+		},
+	}
+
+	for testNumber, test := range tests {
+
+		var actual nul.Nullable[bool]
+
+		err := json.Unmarshal([]byte(test.JSON), &actual)
+		if nil != err {
+			t.Errorf("For test #%d, did not expect an error but actually got one.", testNumber)
+			t.Logf("ERROR: (%T) %s", err, err)
+			t.Logf("JSON: %q", test.JSON)
+			t.Logf("EXPECTED: %#v", test.Expected)
+			t.Logf("ACTUAL:   %#v", actual)
+			continue
+		}
+
+		{
+			expected := test.Expected
+
+			if expected != actual {
+				t.Errorf("For test #%d, the actual value of the optional type is not what was expected.", testNumber)
+				t.Logf("EXPECTED: %#v", expected)
+				t.Logf("ACTUAL:   %#v", actual)
+				t.Logf("JSON: %q", test.JSON)
+				continue
+			}
+		}
+	}
+}
+
+func TestNullable_UnmarshalJSON_bool_fail(t *testing.T) {
+
+	var op nul.Nullable[bool]
+
+	var jason string = "12345"
+
+	err := json.Unmarshal([]byte(jason), &op)
+	if nil == err {
+		t.Errorf("Expected an error but did not actually get one.")
+		return
+	}
+}
diff --git a/nullable_unmarshaljson_int_test.go b/nullable_unmarshaljson_int_test.go
new file mode 100644
index 0000000..8e2075e
--- /dev/null
+++ b/nullable_unmarshaljson_int_test.go
@@ -0,0 +1,119 @@
+package nul_test
+
+import (
+	"testing"
+
+	"encoding/json"
+
+	"sourcecode.social/reiver/go-nul"
+)
+
+func TestNullable_UnmarshalJSON_int(t *testing.T) {
+
+	tests := []struct{
+		JSON string
+	}{
+		{
+			JSON: `null`,
+		},
+
+
+
+		{
+			JSON: `-65536`,
+		},
+		{
+			JSON: `-65535`,
+		},
+
+
+
+		{
+			JSON: `-256`,
+		},
+		{
+			JSON: `-255`,
+		},
+
+
+
+		{
+			JSON: `-5`,
+		},
+		{
+			JSON: `-4`,
+		},
+		{
+			JSON: `-3`,
+		},
+		{
+			JSON: `-2`,
+		},
+		{
+			JSON: `-1`,
+		},
+		{
+			JSON: `0`,
+		},
+		{
+			JSON: `1`,
+		},
+		{
+			JSON: `2`,
+		},
+		{
+			JSON: `3`,
+		},
+		{
+			JSON: `4`,
+		},
+		{
+			JSON: `5`,
+		},
+
+
+
+		{
+			JSON: `-255`,
+		},
+		{
+			JSON: `-256`,
+		},
+
+
+
+		{
+			JSON: `65535`,
+		},
+		{
+			JSON: `65536`,
+		},
+	}
+
+	for testNumber, test := range tests {
+
+		var actual nul.Nullable[int]
+
+		err := json.Unmarshal([]byte(test.JSON), &actual)
+		if nil == err {
+			t.Errorf("For test #%d, expected an error but did not actually get one.", testNumber)
+			t.Logf("ERROR: (%T) %s", err, err)
+			t.Logf("JSON: %q", test.JSON)
+			t.Logf("ACTUAL:   %#v", actual)
+			continue
+		}
+	}
+}
+
+func TestNullable_UnmarshalJSON_int_fail(t *testing.T) {
+
+	var op nul.Nullable[int]
+
+	var jason string = "12345"
+
+	err := json.Unmarshal([]byte(jason), &op)
+	if nil == err {
+		t.Errorf("Expected an error but did not actually get one.")
+		return
+	}
+}
diff --git a/nullable_unmarshaljson_string_test.go b/nullable_unmarshaljson_string_test.go
new file mode 100644
index 0000000..38aab38
--- /dev/null
+++ b/nullable_unmarshaljson_string_test.go
@@ -0,0 +1,132 @@
+package nul_test
+
+import (
+	"testing"
+
+	"encoding/json"
+
+	"sourcecode.social/reiver/go-nul"
+)
+
+func TestNullable_UnmarshalJSON_string(t *testing.T) {
+
+	tests := []struct{
+		JSON string
+		Expected nul.Nullable[string]
+	}{
+		{
+			JSON: `null`,
+			Expected: nul.Null[string](),
+		},
+
+
+
+		{
+			JSON: `""`,
+			Expected: nul.Something(""),
+		},
+
+
+
+		{
+			JSON: `"apple"`,
+			Expected: nul.Something("apple"),
+		},
+		{
+			JSON: `"banana"`,
+			Expected: nul.Something("banana"),
+		},
+		{
+			JSON: `"cherry"`,
+			Expected: nul.Something("cherry"),
+		},
+
+
+
+		{
+			JSON: `"ONCE"`,
+			Expected: nul.Something("ONCE"),
+		},
+		{
+			JSON: `"TWICE"`,
+			Expected: nul.Something("TWICE"),
+		},
+		{
+			JSON: `"THRICE"`,
+			Expected: nul.Something("THRICE"),
+		},
+		{
+			JSON: `"FOURCE"`,
+			Expected: nul.Something("FOURCE"),
+		},
+
+
+
+		{
+			JSON: `"🙂"`,
+			Expected: nul.Something("🙂"),
+		},
+		{
+			JSON: `"😈"`,
+			Expected: nul.Something("😈"),
+		},
+		{
+			JSON: `"❤️"`,
+			Expected: nul.Something("❤️"),
+		},
+
+
+
+		{
+			JSON: `"٠١٢٣۴۵۶٧٨٩"`,
+			Expected: nul.Something("٠١٢٣۴۵۶٧٨٩"),
+		},
+
+
+
+		{
+			JSON: `"𐏑𐏓𐏕"`,
+			Expected: nul.Something("𐏑𐏓𐏕"),
+		},
+	}
+
+	for testNumber, test := range tests {
+
+		var actual nul.Nullable[string]
+
+		err := json.Unmarshal([]byte(test.JSON), &actual)
+		if nil != err {
+			t.Errorf("For test #%d, did not expect an error but actually got one.", testNumber)
+			t.Logf("ERROR: (%T) %s", err, err)
+			t.Logf("JSON: %q", test.JSON)
+			t.Logf("EXPECTED: %#v", test.Expected)
+			t.Logf("ACTUAL:   %#v", actual)
+			continue
+		}
+
+		{
+			expected := test.Expected
+
+			if expected != actual {
+				t.Errorf("For test #%d, the actual value of the nullable optional type is not what was expected.", testNumber)
+				t.Logf("EXPECTED: %#v", expected)
+				t.Logf("ACTUAL:   %#v", actual)
+				t.Logf("JSON: %q", test.JSON)
+				continue
+			}
+		}
+	}
+}
+
+func TestNullable_UnmarshalJSON_string_fail(t *testing.T) {
+
+	var op nul.Nullable[string]
+
+	var jason string = "12345"
+
+	err := json.Unmarshal([]byte(jason), &op)
+	if nil == err {
+		t.Errorf("Expected an error but did not actually get one.")
+		return
+	}
+}