diff --git a/pyproject.toml b/pyproject.toml
index 55760e7b2..362e5a9a1 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -37,7 +37,6 @@ dependencies = [
     "einx[torch]==0.2.2",
     "zstandard>=0.22.0",
     "pydub",
-    "pyaudio",
     "modelscope==1.17.1",
     "opencc-python-reimplemented==0.1.7",
     "silero-vad",
@@ -70,6 +69,9 @@ cu129 = [
   "torch==2.8.0",
   "torchaudio",
 ]
+# Optional: native audio playback for the streaming api_client (PyAudio needs
+# system PortAudio headers; keeping it out of core unblocks slim / headless installs).
+client = ["pyaudio"]
 
 [tool.uv]
 override-dependencies = [
diff --git a/tools/api_client.py b/tools/api_client.py
index 31898aed0..c6e8fb998 100644
--- a/tools/api_client.py
+++ b/tools/api_client.py
@@ -4,7 +4,6 @@
 import wave
 
 import ormsgpack
-import pyaudio
 import requests
 from pydub import AudioSegment
 from pydub.playback import play
@@ -198,6 +197,14 @@ def parse_args():
 
     if response.status_code == 200:
         if args.streaming:
+            try:
+                import pyaudio
+            except ImportError:
+                raise ImportError(
+                    "Streaming playback requires PyAudio. Install it with: "
+                    "pip install -e .[client]"
+                )
+
             p = pyaudio.PyAudio()
             audio_format = pyaudio.paInt16  # Assuming 16-bit PCM format
             stream = p.open(