diff --git a/README.md b/README.md
index a472a49..cd72d31 100644
--- a/README.md
+++ b/README.md
@@ -60,6 +60,9 @@ Important defaults:
 - sample rate: `16000`
 - endpoint: `/ws`
 
+Optional input audio filtering can be enabled through `audio_filter`. See
+`docs/deepfilternet.md` for the DeepFilterNet real-time filter setup.
+
 Product endpoint:
 
 ```text
diff --git a/config.json b/config.json
index 64f64af..2f2a8fb 100644
--- a/config.json
+++ b/config.json
@@ -11,6 +11,16 @@
     "channels": 1,
     "frame_ms": 20
   },
+  "audio_filter": {
+    "enabled": false,
+    "provider": "deepfilternet",
+    "lib_path": null,
+    "model_path": null,
+    "model_sample_rate_hz": 48000,
+    "atten_lim_db": 100.0,
+    "post_filter_beta": 0.0,
+    "log_level": null
+  },
   "session": {
     "inactivity_timeout_sec": 60
   },