diff --git a/src/device/input/button/parser_test.go b/src/device/input/button/parser_test.go
index 55adf25..af5db09 100644
--- a/src/device/input/button/parser_test.go
+++ b/src/device/input/button/parser_test.go
@@ -7,5 +7,5 @@ import (
 
 func TestParser(t *testing.T) {
 	var _ button.Parser = button.Plaintext{}
-	var _ button.Parser = button.V01{}
+	var _ button.Parser = &button.V01{}
 }
diff --git a/src/device/input/button/v01.go b/src/device/input/button/v01.go
index 4732ae0..8f8c059 100644
--- a/src/device/input/button/v01.go
+++ b/src/device/input/button/v01.go
@@ -3,6 +3,7 @@ package button
 import (
 	"context"
 	"encoding/json"
+	"io"
 	"io/ioutil"
 	"log"
 	"mayhem-party/src/device/input/raw"
@@ -46,12 +47,12 @@ type (
 	v01Transformation map[string]string
 )
 
-func NewV01(ctx context.Context, src raw.Raw) V01 {
+func NewV01(ctx context.Context, src raw.Raw) *V01 {
 	var cfg v01Cfg
 	b, _ := ioutil.ReadFile(FlagButtonV01Config)
 	yaml.Unmarshal(b, &cfg)
 	ctx, can := context.WithCancel(ctx)
-	result := V01{
+	result := &V01{
 		ctx: ctx,
 		can: can,
 		src: src,
@@ -61,19 +62,26 @@ func NewV01(ctx context.Context, src raw.Raw) V01 {
 	return result
 }
 
-func (v01 V01) listen() {
+func (v01 *V01) listen() {
 	if v01.cfg.Feedback.Addr == "" {
 		return
 	}
 	s := &http.Server{
 		Addr: v01.cfg.Feedback.Addr,
 		Handler: http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-			r = r.WithContext(v01.ctx)
-			user, ok := v01.cfg.Users[r.URL.Query().Get("user")]
-			if !ok {
-				user = v01.cfg.Users["broadcast"]
+			if r.Method == http.MethodGet {
+				r = r.WithContext(v01.ctx)
+				user, ok := v01.cfg.Users[r.URL.Query().Get("user")]
+				if !ok {
+					user = v01.cfg.Users["broadcast"]
+				}
+				w.Write([]byte(user.Message))
+			} else if r.URL.Path == "/broadcast" {
+				b, _ := io.ReadAll(r.Body)
+				v := v01.cfg.Users["broadcast"]
+				v.Message = string(b)
+				v01.cfg.Users["broadcast"] = v
 			}
-			w.Write([]byte(user.Message))
 		}),
 	}
 	go func() {
@@ -88,17 +96,17 @@ func (v01 V01) listen() {
 	}
 }
 
-func (v01 V01) CloseWrap() raw.Raw {
+func (v01 *V01) CloseWrap() raw.Raw {
 	v01.can()
 	return v01.src
 }
 
-func (v01 V01) Close() {
+func (v01 *V01) Close() {
 	v01.can()
 	v01.src.Close()
 }
 
-func (v01 V01) Read() []Button {
+func (v01 *V01) Read() []Button {
 	line := v01.src.Read()
 	var msg v01Msg
 	if err := json.Unmarshal(line, &msg); err != nil {
@@ -134,7 +142,7 @@ func (t v01Transformation) pipe(s string) string {
 	return s
 }
 
-func (v01 V01) telemetry(msg v01Msg) {
+func (v01 *V01) telemetry(msg v01Msg) {
 	if FlagDebug {
 		log.Printf("%s|%dms", msg.U, time.Now().UnixNano()/int64(time.Millisecond)-msg.T)
 	}
diff --git a/src/device/input/button/v01_exported_test.go b/src/device/input/button/v01_exported_test.go
index 73e5a99..e8b4501 100644
--- a/src/device/input/button/v01_exported_test.go
+++ b/src/device/input/button/v01_exported_test.go
@@ -8,6 +8,7 @@ import (
 	"net/http"
 	"os"
 	"path"
+	"strings"
 	"testing"
 	"time"
 )
@@ -134,4 +135,24 @@ func TestV01Feedback(t *testing.T) {
 			t.Error(b)
 		}
 	})
+
+	t.Run("change broadcast", func(t *testing.T) {
+		want := `my new broadcast`
+		r, _ := http.NewRequest(http.MethodPut, "http://localhost:27071/broadcast", strings.NewReader(want))
+		resp, err := http.DefaultClient.Do(r)
+		if err != nil {
+			t.Fatal(err)
+		}
+		resp.Body.Close()
+
+		resp, err = http.Get("http://localhost:27071")
+		if err != nil {
+			t.Fatal(err)
+		}
+		defer resp.Body.Close()
+		b, _ := io.ReadAll(resp.Body)
+		if string(b) != want {
+			t.Error(string(b))
+		}
+	})
 }