diff --git a/README.md b/README.md
index 3be15fd..75be4e9 100644
--- a/README.md
+++ b/README.md
@@ -228,6 +228,8 @@ the models BigSet uses for schema inference and agents.
 
 OpenRouter is pay-as-you-go; $5-10 is plenty to start.
 
+**Using a different gateway:** BigSet also works with [OrcaRouter](https://www.orcarouter.ai), an OpenAI-compatible router that exposes 200+ models (OpenAI, Anthropic, Google, DeepSeek, ...) behind a single API key. Set `OPENROUTER_BASE_URL=https://api.orcarouter.ai/v1` in `.env` and paste your `sk-orca-...` key into the setup screen. OrcaRouter uses the same `provider/model` id format as OpenRouter, so BigSet's default model slugs (e.g. `anthropic/claude-sonnet-4.6`) work as-is.
+
 > **Note:** root `.env` is the only local env file. If you edit Convex functions in `frontend/convex/`, run `make convex-push` to deploy the changes.
 
 > **Free tier:** cloud signed-in accounts get **2,500 row operations per calendar month** (resets on the 1st, UTC). Local mode bypasses the cloud quota and uses your TinyFish/OpenRouter accounts directly.
@@ -296,6 +298,7 @@ If you want a completely fresh start: `make clean` then `make dev`.
 | Variable | Required | Where to get it |
 |----------|----------|----------------|
 | `CONVEX_SELF_HOSTED_ADMIN_KEY` | Auto | Auto-generated by `make dev` on first run |
+| `OPENROUTER_BASE_URL` | Optional | Defaults to `https://openrouter.ai/api/v1`. Point BigSet at any OpenAI-compatible gateway, e.g. OrcaRouter (`https://api.orcarouter.ai/v1`). |
 | `LOCAL_KEYCHAIN_PORT`, `LOCAL_KEYCHAIN_TOKEN`, `BIGSET_LOCAL_WORKSPACE_ID` | Auto | Auto-generated by `make dev` for local OS keychain access |
 | `RESEND_API_KEY` | Optional | For "dataset ready" emails. Leave blank to skip. |
 | `NEXT_PUBLIC_POSTHOG_KEY` | Optional | For product analytics. Leave blank to disable. |
diff --git a/backend/src/local-credentials.ts b/backend/src/local-credentials.ts
index a6a5b4b..fb2ff69 100644
--- a/backend/src/local-credentials.ts
+++ b/backend/src/local-credentials.ts
@@ -254,11 +254,21 @@ export async function verifyOpenRouterApiKey(apiKey: string): Promise<void> {
 
   await withFetchTimeout(
     async (signal) => {
-      const response = await fetch(`${baseUrl}/key`, {
+      let response = await fetch(`${baseUrl}/key`, {
         headers: { Authorization: `Bearer ${apiKey}` },
         signal,
       });
 
+      // OpenAI-compatible gateways that don't implement OpenRouter's `/key`
+      // endpoint (e.g. OrcaRouter) can still be verified with a lightweight
+      // authenticated request — `/models` returns 401 for invalid keys.
+      if (response.status === 404) {
+        response = await fetch(`${baseUrl}/models`, {
+          headers: { Authorization: `Bearer ${apiKey}` },
+          signal,
+        });
+      }
+
       if (!response.ok) {
         if (response.status === 401 || response.status === 403) {
           throw new Error("OpenRouter rejected that API key.");