Merge pull request #957 from contributor (Netlify Backend Proxy)

Author: devanshi14malhotra

README.md

@@ -103,7 +103,48 @@ It feels like:
 | Storage | LocalStorage |
 
 ---
+## 🚀 Backend Deployment & BACKEND_URL Setup
 
+> ⚠️ The frontend is deployed on Netlify, but the Flask backend is **not yet deployed**.
+> Google Sign-In and all AI features require the backend to be running.
+
+### Why is this needed?
+When a user clicks "Sign in with Google", the browser sends a request to `/api/v1/auth/google`.
+Netlify needs to know where to forward that request, that's what `BACKEND_URL` is for.
+Without it, Netlify has no rule for `/api/v1/*` and shows a 404 error.
+
+### Step 1 — Deploy the Flask backend
+
+You can deploy the backend (located in the `/backend` folder) to either:
+
+| Platform | Free Tier | Docs |
+|---|---|---|
+| [Render](https://render.com) | ✅ Yes | [Render Python Docs](https://render.com/docs/deploy-flask) |
+| [Railway](https://railway.app) | ✅ Yes | [Railway Docs](https://docs.railway.app) |
+
+After deploying, you'll get a public URL like:
+https://your-app.onrender.com
+
+### Step 2 — Set BACKEND_URL in Netlify
+
+1. Go to [Netlify Dashboard](https://app.netlify.com)
+2. Open your site → **Site Configuration → Environment Variables**
+3. Click **Add a variable**
+4. Set:
+   - **Key:** `BACKEND_URL`
+   - **Value:** `https://your-app.onrender.com` *(no trailing slash)*
+5. Click **Save**
+
+### Step 3 — Redeploy the Netlify site
+
+After setting the variable:
+1. Go to **Deploys** tab in your Netlify dashboard
+2. Click **Trigger deploy → Deploy site**
+3. This reruns `build_netlify.py`, which picks up `BACKEND_URL` and adds the proxy rule to `_redirects`
+
+After this, "Sign in with Google" will correctly reach the Flask backend. ✅
+
+---
 ## 🧠 System Architecture
 
 ```mermaid

build_netlify.py

@@ -57,7 +57,16 @@ def build_html() -> None:
 
 
 def write_clean_route_redirects() -> None:
-    redirects = [
+    redirects = []
+
+    # if BACKEND_URL is set in Netlify's environment variables,
+    # proxy all /api/v1/* requests to the Flask backend.
+    # without this, Netlify has no rule for /api/v1/ and shows a 404.
+    backend_url = os.getenv("BACKEND_URL", "").strip().rstrip("/")
+    if backend_url:
+        redirects.append(f"/api/v1/* {backend_url}/api/v1/:splat 200")
+
+    redirects += [
         "/app /app.html 200",
         "/chat /chat.html 200",
         "/auth /auth.html 200",

netlify.toml

@@ -5,6 +5,9 @@ functions = "netlify/functions"
 
 [build.environment]
 PYTHON_VERSION = "3.10"
+# BACKEND_URL is intentionally not set here: never commit secrets to the repo.
+# Set it in: Netlify Dashboard → Site Configuration → Environment Variables
+# Example value: https://your-app.onrender.com
 
 [[headers]]
   for = "/*.gltf"