Add Upstash guide with Bun Redis (#24493)

docs/docs.json

@@ -375,7 +375,8 @@
               "/guides/ecosystem/stric",
               "/guides/ecosystem/sveltekit",
               "/guides/ecosystem/systemd",
-              "/guides/ecosystem/vite"
+              "/guides/ecosystem/vite",
+              "/guides/ecosystem/upstash"
             ]
           },
           {

docs/guides/ecosystem/upstash.mdx

@@ -0,0 +1,87 @@
+---
+title: Bun Redis with Upstash
+sidebarTitle: Upstash with Bun
+mode: center
+---
+
+[Upstash](https://upstash.com/) is a fully managed Redis database as a service. Upstash works with the Redis® API, which means you can use Bun's native Redis client to connect to your Upstash database.
+
+<Note>TLS is enabled by default for all Upstash Redis databases.</Note>
+
+---
+
+<Steps>
+  <Step title="Create a new project">
+    Create a new project by running `bun init`:
+    
+    ```sh terminal icon="terminal"
+    bun init bun-upstash-redis
+    cd bun-upstash-redis
+    ```
+  </Step>
+  <Step title="Create an Upstash Redis database">
+    Go to the [Upstash dashboard](https://console.upstash.com/) and create a new Redis database. After completing the [getting started guide](https://upstash.com/docs/redis/overall/getstarted), you'll see your database page with connection information.
+
+    The database page displays two connection methods; HTTP and TLS. For Bun's Redis client, you need the **TLS** connection details. This URL starts with `rediss://`.
+
+    	<Frame>
+    		![Upstash Redis database page](/images/guides/upstash-1.png)
+    	</Frame>
+
+  </Step>
+  <Step title="Connect using Bun's Redis client">
+		You can connect to Upstash by setting environment variables with Bun's default `redis` client.
+
+    Set the `REDIS_URL` environment variable in your `.env` file using the Redis endpoint (not the REST URL):
+
+    ```env .env icon="settings"
+    REDIS_URL=rediss://********@********.upstash.io:6379
+    ```
+
+    Bun's Redis client reads connection information from `REDIS_URL` by default:
+
+    ```ts index.ts icon="/icons/typescript.svg"
+    import { redis } from "bun";
+
+    // Reads from process.env.REDIS_URL automatically
+    await redis.set("counter", "0"); // [!code ++]
+    ```
+
+    Alternatively, you can create a custom client using `RedisClient`:
+
+    ```ts index.ts icon="/icons/typescript.svg"
+    import { RedisClient } from "bun";
+
+    const redis = new RedisClient(process.env.REDIS_URL); // [!code ++]
+    ```
+
+  </Step>
+	<Step title="Use the Redis client">
+		You can now use the Redis client to interact with your Upstash Redis database:
+
+    	```ts index.ts icon="/icons/typescript.svg"
+    	import { redis } from "bun";
+
+    	// Get a value
+    	let counter = await redis.get("counter");
+
+    	// Set a value if it doesn't exist
+    	if (!counter) {
+    		await redis.set("counter", "0");
+    	}
+
+    	// Increment the counter
+    	await redis.incr("counter");
+
+    	// Get the updated value
+    	counter = await redis.get("counter");
+    	console.log(counter);
+    	```
+    	```txt
+    	1
+    	```
+
+    	The Redis client automatically handles connections in the background. No need to manually connect or disconnect for basic operations.
+    </Step>
+
+</Steps>