diff --git a/abogen/integrations/audiobookshelf.py b/abogen/integrations/audiobookshelf.py
index f44c58a..1c215ac 100644
--- a/abogen/integrations/audiobookshelf.py
+++ b/abogen/integrations/audiobookshelf.py
@@ -51,6 +51,11 @@ class AudiobookshelfClient:
         self._config = config
         self._base_url = config.normalized_base_url()
 
+    def _api_path(self, suffix: str = "") -> str:
+        """Join the API prefix with the provided suffix without losing proxies."""
+        clean_suffix = suffix.lstrip("/")
+        return f"api/{clean_suffix}" if clean_suffix else "api"
+
     def upload_audiobook(
         self,
         audio_path: Path,
@@ -111,7 +116,7 @@ class AudiobookshelfClient:
             payload["collectionId"] = self._config.collection_id
         try:
             with self._open_client() as client:
-                response = client.post("/api/uploads", json=payload)
+                response = client.post(self._api_path("uploads"), json=payload)
                 response.raise_for_status()
                 return response.json()
         except httpx.HTTPError as exc:
@@ -121,7 +126,7 @@ class AudiobookshelfClient:
         mime_type, _ = mimetypes.guess_type(path.name)
         mime_type = mime_type or "application/octet-stream"
         data = {"kind": kind, "filename": path.name}
-        route = f"/api/uploads/{upload_id}/files"
+        route = self._api_path(f"uploads/{upload_id}/files")
         try:
             with path.open("rb") as handle:
                 files = {"file": (path.name, handle, mime_type)}
@@ -144,7 +149,7 @@ class AudiobookshelfClient:
         return payload
 
     def _finalize_upload(self, upload_id: str, payload: Dict[str, Any]) -> Dict[str, Any]:
-        route = f"/api/uploads/{upload_id}/finish"
+        route = self._api_path(f"uploads/{upload_id}/finish")
         try:
             with self._open_client() as client:
                 response = client.post(route, json=payload)
diff --git a/abogen/web/routes.py b/abogen/web/routes.py
index 387a5c0..8512eab 100644
--- a/abogen/web/routes.py
+++ b/abogen/web/routes.py
@@ -3044,7 +3044,7 @@ def test_audiobookshelf() -> ResponseReturnValue:
 
     try:
         with client._open_client() as http_client:  # pylint: disable=protected-access
-            response = http_client.get("/api/libraries", params={"lite": "true"})
+            response = http_client.get(client._api_path("libraries"), params={"lite": "true"})
             response.raise_for_status()
             payload_json = response.json()
     except Exception as exc:  # pragma: no cover - network guard
@@ -3081,7 +3081,7 @@ def test_audiobookshelf() -> ResponseReturnValue:
     if collection_id:
         try:
             with client._open_client() as http_client:  # pylint: disable=protected-access
-                collection_resp = http_client.get(f"/api/collections/{collection_id}")
+                collection_resp = http_client.get(client._api_path(f"collections/{collection_id}"))
                 collection_resp.raise_for_status()
         except Exception as exc:  # pragma: no cover - network guard
             status_code = getattr(getattr(exc, "response", None), "status_code", None)