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Get up and running with Lettr in minutes. Choose the integration path that matches your stack. Using Cursor? Jump straight in using this prompt

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Prerequisites

Before you begin, make sure you have:
  1. A Lettr account — sign up at app.lettr.com
  2. An API key created in your dashboard
  3. A verified sending domain

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Choose Your Integration

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By Language / Framework

PHP

Laravel, Symfony, or plain PHP

Node.js

Next.js, Nuxt, or plain Node.js

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By Protocol

SMTP

Connect via SMTP relay — works with any language or framework

REST API

Send emails with a single HTTP POST request

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By Platform

AWS Lambda

Serverless email sending on AWS

Vercel

Send emails from Vercel functions

Cloudflare Workers

Send emails from Workers

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Fastest Path

The quickest way to send your first email is a single API call: 
curl -X POST https://app.lettr.com/api/emails \
  -H "Authorization: Bearer lttr_xxxxxxxxxxxx" \
  -H "Content-Type: application/json" \
  -d '{
    "from": "you@yourdomain.com",
    "to": ["recipient@example.com"],
    "subject": "Hello from Lettr",
    "html": "<p>Your first email!</p>"
  }'
For the complete API reference, see the Send Email endpoint.

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Pre-Built Integrations

Using a third-party platform? Check our integration guides for ready-made setups:

Stripe

Send emails from Stripe

Supabase

Auth emails and Edge Functions

WordPress

Replace wp_mail with Lettr