> ## Documentation Index
> Fetch the complete documentation index at: https://upstash.com/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# AWS Lambda

<Snippet file="redis/start-redis-snippet.mdx" />

<Card title="GitHub Repository" icon="github" href="https://github.com/upstash/redis-js/tree/main/examples/aws-cdk-typescript" horizontal>
  You can find the project source code on GitHub.
</Card>

### Prerequisites

* Complete all steps in [Getting started with the AWS CDK](https://docs.aws.amazon.com/cdk/v2/guide/getting_started.html)

### Project Setup

Create and navigate to a directory named `counter-cdk`. The CDK CLI uses this directory name to name things in your CDK code, so if you decide to use a different name, don't forget to make the appropriate changes when applying this tutorial.

```shell theme={"system"}
mkdir counter-cdk && cd counter-cdk
```

Initialize a new CDK project.

```shell theme={"system"}
cdk init app --language typescript
```

Install `@upstash/redis`.

```shell theme={"system"}
npm install @upstash/redis
```

### Counter Function Setup

Create `/api/counter.ts`.

```ts /api/counter.ts theme={"system"}
import { Redis } from '@upstash/redis';

const redis = Redis.fromEnv();

export const handler = async function() {
    const count = await redis.incr("counter");
    return {
        statusCode: 200,
        body: JSON.stringify('Counter: ' + count),
    };
};
```

### Counter Stack Setup

Update `/lib/counter-cdk-stack.ts`.

```ts /lib/counter-cdk-stack.ts theme={"system"}
import * as cdk from 'aws-cdk-lib';
import { Construct } from 'constructs';
import * as lambda from 'aws-cdk-lib/aws-lambda';
import * as nodejs from 'aws-cdk-lib/aws-lambda-nodejs';

export class CounterCdkStack extends cdk.Stack {
  constructor(scope: Construct, id: string, props?: cdk.StackProps) {
    super(scope, id, props);

    const counterFunction = new nodejs.NodejsFunction(this, 'CounterFunction', {
      entry: 'api/counter.ts',
      handler: 'handler',
      runtime: lambda.Runtime.NODEJS_20_X,
      environment: {
        UPSTASH_REDIS_REST_URL: process.env.UPSTASH_REDIS_REST_URL || '',
        UPSTASH_REDIS_REST_TOKEN: process.env.UPSTASH_REDIS_REST_TOKEN || '',
      },
      bundling: {
        format: nodejs.OutputFormat.ESM,
        target: "node20",
        nodeModules: ['@upstash/redis'],
      },
    });

    const counterFunctionUrl = counterFunction.addFunctionUrl({
      authType: lambda.FunctionUrlAuthType.NONE,
    });

    new cdk.CfnOutput(this, "counterFunctionUrlOutput", {
      value: counterFunctionUrl.url,
    })
  }
}
```

### Database Setup

Create a Redis database using [Upstash Console](https://console.upstash.com) or [Upstash CLI](https://github.com/upstash/cli) and export `UPSTASH_REDIS_REST_URL` and `UPSTASH_REDIS_REST_TOKEN` to your environment.

```shell theme={"system"}
export UPSTASH_REDIS_REST_URL=<YOUR_URL>
export UPSTASH_REDIS_REST_TOKEN=<YOUR_TOKEN>
```

### Deploy

Run in the top folder:

```shell theme={"system"}
cdk synth
cdk bootstrap
cdk deploy
```

Visit the output URL.