feat: add OpenRouter as 8th provider

studio/backend/core/inference/external_provider.py

@@ -34,10 +34,17 @@ class ExternalProviderClient:
 
     def _auth_headers(self) -> dict[str, str]:
         """Build authentication headers. All supported providers use Bearer tokens."""
-        return {
+        from core.inference.providers import get_provider_info
+
+        headers = {
             "Authorization": f"Bearer {self.api_key}",
             "Content-Type": "application/json",
         }
+        # Merge any provider-specific extra headers (e.g. OpenRouter attribution headers)
+        provider_info = get_provider_info(self.provider_type)
+        if provider_info:
+            headers.update(provider_info.get("extra_headers", {}))
+        return headers
 
     async def stream_chat_completion(
         self,

studio/backend/core/inference/providers.py

@@ -119,6 +119,27 @@ PROVIDER_REGISTRY: dict[str, dict[str, Any]] = {
         "auth_prefix": "Bearer ",
         "notes": "Web-grounded responses with built-in search.",
     },
+    "openrouter": {
+        "display_name": "OpenRouter",
+        "base_url": "https://openrouter.ai/api/v1",
+        "default_models": [
+            "openai/gpt-4o",
+            "anthropic/claude-sonnet-4-5",
+            "google/gemini-2.5-flash",
+            "meta-llama/llama-4-maverick",
+            "mistralai/mistral-small-3.1-24b-instruct",
+        ],
+        "supports_streaming": True,
+        "supports_vision": True,
+        "supports_tool_calling": True,
+        "auth_header": "Authorization",
+        "auth_prefix": "Bearer ",
+        "extra_headers": {
+            "HTTP-Referer": "https://unsloth.ai",
+            "X-Title": "Unsloth Studio",
+        },
+        "notes": "Unified gateway to 300+ models across all major providers. HTTP-Referer and X-Title headers sent for attribution.",
+    },
 }
 
 

studio/backend/tests/test_providers_api.py

@@ -48,6 +48,7 @@ _PROVIDER_CONFIGS: dict[str, tuple[str, str]] = {
     "together":   ("TOGETHER_API_KEY",  "meta-llama/Llama-4-Maverick-17B-128E-Instruct-FP8"),
     "fireworks":  ("FIREWORKS_API_KEY", "accounts/fireworks/models/llama4-maverick-instruct-basic"),
     "perplexity": ("PERPLEXITY_API_KEY", "sonar"),
+    "openrouter": ("OPENROUTER_API_KEY", "openai/gpt-4o-mini"),
 }
 
 PROVIDER_KEYS: dict[str, str] = {
@@ -230,7 +231,7 @@ class TestPublicKey:
 
 
 class TestRegistry:
-    def test_registry_returns_7_providers(self, auth_headers: dict[str, str]):
+    def test_registry_returns_8_providers(self, auth_headers: dict[str, str]):
         """GET /api/providers/registry returns all 7 supported providers."""
         resp = requests.get(
             _url("/api/providers/registry"),
@@ -239,7 +240,7 @@ class TestRegistry:
         )
         assert resp.status_code == 200, f"Registry failed: {resp.text}"
         providers = resp.json()
-        assert len(providers) == 7, f"Expected 7 providers, got {len(providers)}: {providers}"
+        assert len(providers) == 8, f"Expected 8 providers, got {len(providers)}: {providers}"
         print(f"\n  {'Provider':<12} {'Base URL'}")
         print(f"  {'-'*12} {'-'*45}")
         for p in providers: