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

# Official Lettr SDKs

> Browse the official Lettr SDKs for Node.js, PHP, Python, Go, Rust, and Java, each with a quickstart guide to get you sending email fast.

Official Lettr SDKs for all major programming languages. Each SDK has a guide to get you sending in minutes — follow the card for your language, then use the [API reference](/api-reference/introduction) for full endpoint details.

## Official SDKs

<CardGroup cols={2}>
  <Card title="Node.js" icon="node-js" href="/quickstart/nodejs/introduction">
    ```bash theme={null}
    npm install lettr
    ```
  </Card>

  <Card title="PHP" icon="php" href="/quickstart/php/introduction">
    ```bash theme={null}
    composer require lettr/lettr-php
    ```
  </Card>

  <Card title="Python" icon="python" href="/quickstart/python/quickstart">
    ```bash theme={null}
    pip install lettr
    ```
  </Card>

  <Card title="Go" icon="golang" href="/quickstart/go/quickstart">
    ```bash theme={null}
    go get github.com/lettr-com/lettr-go
    ```
  </Card>

  <Card title="Rust" icon="rust" href="/quickstart/rust/quickstart">
    ```bash theme={null}
    cargo add lettr
    ```
  </Card>

  <Card title="Java" icon="java" href="/quickstart/java/quickstart">
    ```xml theme={null}
    <dependency>
      <groupId>com.lettr</groupId>
      <artifactId>lettr-java</artifactId>
      <version>1.1.0</version>
    </dependency>
    ```
  </Card>
</CardGroup>

## Framework Integrations

<CardGroup cols={3}>
  <Card title="Laravel" icon="laravel" href="/quickstart/laravel/introduction">
    Official Laravel package
  </Card>

  <Card title="Next.js" icon="react" href="/quickstart/nodejs/nextjs">
    Send from Next.js apps
  </Card>

  <Card title="Nuxt" icon="vuejs" href="/quickstart/nodejs/nuxt">
    Send from Nuxt apps
  </Card>

  <Card title="Flask" icon="python" href="/quickstart/python/send-with-flask">
    Send from Flask apps
  </Card>

  <Card title="FastAPI" icon="python" href="/quickstart/python/send-with-fastapi">
    Send from FastAPI apps
  </Card>

  <Card title="Serverless" icon="bolt" href="/quickstart/serverless/introduction">
    AWS Lambda, Vercel, Cloudflare
  </Card>
</CardGroup>

## SDK Features

All SDKs include:

| Feature              | Description                        |
| -------------------- | ---------------------------------- |
| Type definitions     | Full TypeScript/type hints support |
| Error handling       | Structured error responses         |
| Automatic retries    | Retry on transient failures        |
| Webhook verification | Built-in signature verification    |
| Rate limiting        | Automatic rate limit handling      |

## Source & Contributing

SDKs are open source on [GitHub](https://github.com/lettr-com). Each repository's README has install notes and a hello-world example; full usage lives in the per-language guides above and the [API reference](/api-reference/introduction).

<Card title="Contribution Guide" icon="code-pull-request" href="https://github.com/lettr/lettr-node/blob/main/CONTRIBUTING.md">
  Learn how to contribute to our SDKs
</Card>