diff --git a/src/adapters/openai_adapter.py b/src/adapters/openai_adapter.py
index bc0c894..526641b 100644
--- a/src/adapters/openai_adapter.py
+++ b/src/adapters/openai_adapter.py
@@ -17,10 +17,14 @@ logger = logging.getLogger(__name__)
 class OpenAIAdapter(ModelAdapter):
     """Adapter for the OpenAI API (GPT-4o, o1, etc.)."""
 
-    def __init__(self, api_key: str | None = None) -> None:
-        self._client = AsyncOpenAI(
-            api_key=api_key or settings.openai_api_key,
-        )
+    def __init__(self, api_key: str | None = None, base_url: str | None = None) -> None:
+        kwargs: dict[str, Any] = {
+            "api_key": api_key or settings.openai_api_key,
+        }
+        url = base_url or settings.openai_base_url
+        if url:
+            kwargs["base_url"] = url
+        self._client = AsyncOpenAI(**kwargs)
 
     # ------------------------------------------------------------------
     # Streaming
diff --git a/src/config.py b/src/config.py
index 1e7e9eb..a30bf59 100644
--- a/src/config.py
+++ b/src/config.py
@@ -30,6 +30,7 @@ class Settings(BaseSettings):
     # --- Model providers ---
     anthropic_api_key: str = ""
     openai_api_key: str = ""
+    openai_base_url: str = ""  # Custom base URL (for MiniMax, DeepInfra, etc.)
     default_model_provider: str = "claude"
     default_model_id: str = "claude-sonnet-4-20250514"
     max_tokens: int = 4096