[AI Gateway]: Add unified billing docs (#24728)

* [AI Gateway]: Add unified billing docs

* fix: typo, add spend limit docs

Author: palashgo

src/content/docs/ai-gateway/features/unified-billing.mdx

@@ -0,0 +1,71 @@
+
+---
+pcx_content_type: configuration
+title: Unified Billing
+sidebar:
+  order: 1
+head: []
+description: Use the Cloudflare billing to pay for and authenticate your inference requests.
+---
+
+:::caution
+Unified Billing is in closed beta. Request for access.
+:::
+
+Unified Billing allows users to connect to various AI providers (e.g. OpenAI, Anthropic) and receive a single Cloudflare bill. To use Unified Billing, users must purchase and load credits into their Cloudflare account, via the Dashboard, which can then be spent via the AI Gateway.
+
+
+### Load credits
+
+- Navigate to [AI Gateway](https://dash.cloudflare.com/?to=/:account/ai/ai-gateway) on Cloudflare dashboard
+- The "Credits Available" card on the top right shows how many AI gateway credits you have on your account currently. 
+- Click "Manage" to navigate to the new billing page
+- If you don't have a payment method already on your account, you will be prompted to "Add a payment method to purchase credits" on top of page. 
+- Once you have a card added, you will be able to do a credit top up on your account by clicking "Top-up credits", and then adding the required amount on the next popup.
+
+
+### Auto-top up
+
+- Navigate to [AI Gateway](https://dash.cloudflare.com/?to=/:account/ai/ai-gateway) on Cloudflare dashboard
+- Click "Manage"  on the "Credits Available" card on the top right to navigate to the new billing page 
+- Click the "Setup auto top-up credits" option on the dashboard, and set up a threshold and a recharge amount for auto topup. 
+
+When your balance falls below the given threshold, we will automatically apply the auto topup on your account.
+
+### Using Unified Billing
+
+#### Pre-requisites
+
+- Ensure your gateway is [authenticated](/ai-gateway/configuration/authentication/).
+
+Call any supported provider without passing any API Key. The request will automatically use Cloudflare's key and deduct credits from your account. 
+
+Example with Unified API:
+
+```bash
+curl -X POST https://gateway.ai.cloudflare.com/v1/{account_id}/{gateway_id}/compat/chat/completions \
+  --header 'cf-aig-authorization: Bearer {CLOUDFLARE_TOKEN}' \
+  --header 'Content-Type: application/json' \
+  --data '{
+    "model": "google-ai-studio/gemini-2.5-pro",
+    "messages": [
+      {
+        "role": "user",
+        "content": "What is Cloudflare?"
+      }
+    ]
+  }'
+```
+
+### Spend limit
+
+Set spend limits to prevent unexpected charges on your loaded credits. You can define daily, weekly, or monthly limits. When a limit is reached, the AI Gateway automatically stops processing requests until the period resets or you increase the limit.
+
+
+### Supported Providers
+
+- [OpenAI](/ai-gateway/usage/providers/openai/)
+- [Anthropic](/ai-gateway/usage/providers/anthropic/)
+- [Google AI Studio](/ai-gateway/usage/providers/google-ai-studio/)
+- [xAI](/ai-gateway/usage/providers/grok/)
+- [Groq](/ai-gateway/usage/providers/groq/)

src/content/docs/ai-gateway/get-started.mdx

@@ -28,6 +28,7 @@ When you enable authentication on gateway each request is required to include a
 
 Authenticate with your upstream provider using one of the following options:
 
+- **Unified Billing:** Use the AI Gateway billing to pay for and authenticate your inference requests. Refer to [Unified Billing](/ai-gateway/features/unified-billing/).
 - **BYOK (Store Keys):** Store your credentials in Cloudflare, and AI Gateway will include them at runtime. Refer to [BYOK](/ai-gateway/configuration/bring-your-own-keys/).
 - **Request headers:** Include your provider key in the request headers as you normally would (for example, `Authorization: Bearer <PROVIDER_API_KEY>`).
 

src/content/docs/ai-gateway/usage/providers/cerebras.mdx

@@ -10,7 +10,7 @@ import { Render } from "~/components";
 ## Endpoint
 
 ```txt
-https://gateway.ai.cloudflare.com/v1/{account_id}/{gateway_id}/cerebras-ai
+https://gateway.ai.cloudflare.com/v1/{account_id}/{gateway_id}/cerebras
 ```
 
 ## Prerequisites

src/content/docs/ai-gateway/usage/providers/grok.mdx

@@ -1,12 +1,10 @@
 ---
-title: Grok
+title: xAI
 pcx_content_type: get-started
 ---
 
 import { Render } from "~/components";
 
-[Grok](https://docs.x.ai/docs#getting-started) is a general purpose model that can be used for a variety of tasks, including generating and understanding text, code, and function calling.
-
 ## Endpoint
 
 ```txt
@@ -23,8 +21,8 @@ When making requests to Grok, ensure you have the following:
 
 - Your AI Gateway Account ID.
 - Your AI Gateway gateway name.
-- An active Grok API token.
-- The name of the Grok model you want to use.
+- An active xAI API token.
+- The name of the xAI model you want to use.
 
 ## Examples
 
@@ -33,9 +31,9 @@ When making requests to Grok, ensure you have the following:
 ```bash title="Request"
 curl https://gateway.ai.cloudflare.com/v1/{account_id}/{gateway_id}/grok/v1/chat/completions \
   --header 'content-type: application/json' \
-  --header 'Authorization: Bearer {grok_api_token}' \
+  --header 'Authorization: Bearer {xai_api_token}' \
   --data '{
-    "model": "grok-beta",
+    "model": "grok-4",
     "messages": [
         {
             "role": "user",
@@ -59,7 +57,7 @@ const openai = new OpenAI({
 });
 
 const completion = await openai.chat.completions.create({
-	model: "grok-beta",
+	model: "grok-4",
 	messages: [
 		{
 			role: "system",
@@ -91,7 +89,7 @@ client = OpenAI(
 )
 
 completion = client.chat.completions.create(
-    model="grok-beta",
+    model="grok-4",
     messages=[
         {"role": "system", "content": "You are Grok, a chatbot inspired by the Hitchhiker's Guide to the Galaxy."},
         {"role": "user", "content": "What is the meaning of life, the universe, and everything?"},

src/content/docs/ai-gateway/usage/providers/index.mdx

@@ -1,6 +1,6 @@
 ---
 pcx_content_type: navigation
-title: Provider specific
+title: Provider Native
 sidebar:
   group:
     hideIndex: true