Transactional and
marketing email built for SaaS

Your team builds every email in one editor.
You send transactional by API and marketing by campaign. One platform, one bill.

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40,000+

companies use our email editor

12,000+

organizations run campaigns with us

12 years

running email infrastructure

Make all your emails
accessible to everyone

Your devs connect sending once. After that, your team owns the emails.

Dev integrate.

use Illuminate\Support\Facades\Mail;

Mail::lettr()
    ->to($user->email)
    ->sendTemplate('welcome', substitutionData: [
        'first_name' => $user->first_name,
    ]);

import { Lettr } from 'lettr';

const client = new Lettr(process.env.LETTR_API_KEY!);

await client.emails.send({
    from: 'hello@yourdomain.com',
    to: [user.email],
    subject: 'Welcome to Acme',
    templateId: 'welcome',
    substitutionData: { first_name: user.firstName },
});

import os
import lettr

client = lettr.Lettr(os.environ["LETTR_API_KEY"])

client.emails.send(
    from_email="hello@yourdomain.com",
    to=[user.email],
    subject="Welcome to Acme",
    template_id="welcome",
    substitution_data={"first_name": user.first_name},
)

use Lettr\Lettr;

$lettr = Lettr::client(getenv('LETTR_API_KEY'));

$lettr->emails()->send(
    $lettr->emails()->create()
        ->from('hello@yourdomain.com', 'Acme')
        ->to([$user->email])
        ->subject('Welcome to Acme')
        ->templateId('welcome')
        ->substitutionData(['first_name' => $user->firstName])
);

curl -X POST https://app.lettr.com/api/emails \
  -H "Authorization: Bearer $LETTR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "from": "hello@yourdomain.com",
    "to": ["clara@example.com"],
    "template_slug": "welcome",
    "substitution_data": { "first_name": "Clara" }
  }'

Hook it up once,
then get back to your product.

Send with one API call, or point your existing app at our SMTP. Either way, you're live in minutes.
Skip the hand-rolled HTTP calls. Drop in the SDK for your language and send in a few lines.
Know the moment an email is delivered, opened or clicked, and react in your app. Every call is signed, so you can trust it.

Teams create.

trial-welcome-email Draft

Preview

Create mutation

Content

Structure

Settings

Basic

Premade

Saved

Text

Image

Button

Divider

Spacer

Social

Video

HTML

Loop

One quick step, then you're all set.

Your trial is live!

Hi {{first_name}}, thanks for signing up. You have 14 days to explore everything.

Open your dashboard

Change copy, swap images, hit send. No developer needed.

Update a header or footer once and every email follows. No more hunting through templates.
One template, every language. Fix a typo once, not in five copies.
Names, plans, dates: drop them in and each email fills itself in.