From 5d6301d31225b7f6bd338f334532ac0603f2c9a5 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Mon, 9 Mar 2026 20:42:41 -1000
Subject: [PATCH] missing guard

---
 esphome/components/serial_proxy/serial_proxy.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/esphome/components/serial_proxy/serial_proxy.h b/esphome/components/serial_proxy/serial_proxy.h
index e9398e3fa82..5adfa4fe53b 100644
--- a/esphome/components/serial_proxy/serial_proxy.h
+++ b/esphome/components/serial_proxy/serial_proxy.h
@@ -101,8 +101,10 @@ class SerialProxy : public uart::UARTDevice, public Component {
   void set_dtr_pin(GPIOPin *pin) { this->dtr_pin_ = pin; }
 
  protected:
+#ifdef USE_API
   /// Read from UART and send to API client (slow path with 256-byte stack buffer)
   void read_and_send_(size_t available);
+#endif
 
   /// Instance index for identifying this proxy in API messages
   uint32_t instance_index_{0};