> ## 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.

# WordPress

> Install the Lettr WordPress plugin to replace wp_mail and route every email, including WooCommerce and contact forms, through Lettr's API.

The [Lettr WordPress plugin](https://github.com/lettr-com/lettr-wordpress) replaces the default `wp_mail()` function with Lettr's email API. Once activated, every outgoing email from your WordPress site — including emails from WooCommerce, contact form plugins, and any other plugin that uses `wp_mail()` — is sent through Lettr automatically.

No SMTP configuration needed. Just enter your API key and you're ready to go.

## Prerequisites

Before you begin, make sure you have:

<CardGroup cols={2}>
  <Card title="API Key" icon="key" href="https://app.lettr.com/api-keys">
    Create an API key in the Lettr dashboard
  </Card>

  <Card title="Verified Domain" icon="globe" href="/learn/domains/sending-domains">
    Add and verify your sending domain
  </Card>
</CardGroup>

You'll also need:

* WordPress 5.8 or higher
* PHP 7.2 or higher

## Install the Plugin

<Steps>
  <Step title="Download the plugin">
    Download the latest release as a ZIP from the [GitHub repository](https://github.com/lettr-com/lettr-wordpress).
  </Step>

  <Step title="Upload and activate">
    In your WordPress admin panel, go to **Plugins → Add Plugin → Upload Plugin**, upload the ZIP file, click **Install**, and activate the plugin.

    Alternatively, clone or extract the plugin into `/wp-content/plugins/lettr` and activate it from the **Plugins** page.
  </Step>

  <Step title="Configure your API key">
    After activation, you're redirected to the plugin's setup page. Enter your Lettr API key (starts with `lttr_`) and configure your sender name and email address.

    <Warning>
      The sender email must use a domain you've verified in the [Lettr dashboard](https://app.lettr.com/domains). Emails from unverified domains will be rejected.
    </Warning>
  </Step>

  <Step title="Send a test email">
    Use the built-in test email feature to confirm everything is working. Check the [Lettr logs](https://app.lettr.com/logs) to verify delivery.
  </Step>
</Steps>

## How It Works

The plugin overrides WordPress's built-in `wp_mail()` function and routes all emails through the [Lettr Send Email API](/api-reference/emails/send-email). This means:

* **All plugins are covered** — WooCommerce order confirmations, Contact Form 7 submissions, password resets, user notifications, and anything else that calls `wp_mail()`.
* **Attachments are supported** — File attachments are automatically encoded and sent via the API.
* **HTML and plain text** — The plugin detects the content type and sends the appropriate format.
* **Delivery tracking** — Every email appears in your [Lettr logs](https://app.lettr.com/logs) with full delivery status, opens, clicks, and bounces.

<Tip>
  Since the plugin uses the Lettr HTTP API (not SMTP), there's no need to open any ports or configure SMTP settings on your server.
</Tip>

## Troubleshooting

<AccordionGroup>
  <Accordion title="Emails not sending after activation">
    * Verify your API key is correct and starts with `lttr_`
    * Ensure the sender email uses a domain verified in Lettr
    * Check the [Lettr logs](https://app.lettr.com/logs) for error details
    * Confirm another plugin hasn't already overridden `wp_mail()` — the Lettr plugin shows an admin notice if this conflict is detected
  </Accordion>

  <Accordion title="wp_mail conflict with another plugin">
    The Lettr plugin replaces the `wp_mail()` function. If another plugin (e.g. another email delivery plugin) has already declared `wp_mail()`, the Lettr plugin cannot override it and will display a notice in the admin panel. Deactivate the conflicting plugin to resolve this.
  </Accordion>

  <Accordion title="Emails landing in spam">
    Make sure your sending domain has proper DNS records:

    * [SPF](/learn/domains/spf) — Authorizes Lettr to send on your behalf
    * [DKIM](/learn/domains/dkim) — Cryptographically signs your emails
    * [DMARC](/learn/domains/dmarc) — Tells receivers how to handle unauthenticated mail

    See [Deliverability Best Practices](/knowledge-base/best-practices/deliverability) for more tips.
  </Accordion>

  <Accordion title="Attachments not arriving">
    The plugin reads attachments from the local filesystem. Ensure the file paths passed to `wp_mail()` are readable by PHP. Temporary files that are deleted before the API request completes will fail silently.
  </Accordion>
</AccordionGroup>

## Other Integrations

<CardGroup cols={2}>
  <Card title="Stripe" icon="stripe" href="/integrations/stripe">
    Send payment emails from Stripe
  </Card>

  <Card title="Supabase" icon="bolt" href="/integrations/supabase">
    Auth emails and Edge Functions
  </Card>
</CardGroup>

## What's Next

<CardGroup cols={2}>
  <Card title="Sending Domains" icon="globe" href="/learn/domains/sending-domains">
    Verify your sending domain
  </Card>

  <Card title="Templates" icon="paintbrush" href="/learn/templates/introduction">
    Create reusable email templates
  </Card>

  <Card title="Webhooks" icon="webhook" href="/learn/webhooks/introduction">
    Track delivery events in real-time
  </Card>

  <Card title="Deliverability" icon="chart-line" href="/knowledge-base/best-practices/deliverability">
    Improve email deliverability
  </Card>
</CardGroup>