Transactional Email Template Development with MJML

We built an email campaign for an online store. The layout was table-based, tested in Gmail — all good. But in Outlook 2016, the email fell apart: button misaligned, fonts missing, image not loading. Sound familiar? MJML fixes this.

The problem is that Outlook uses Word for HTML rendering, not Edge or WebKit. According to Litmus stats, about 9% of users open emails in Outlook. MJML solves this pain: you write components in a declarative language, and the output is valid table HTML tested in over 90 email clients. We use MJML together with Handlebars and Node.js so that templates are not only beautiful but also easily integrated with any backend.

Why MJML saves you from Outlook headaches

MJML ensures Outlook compatibility by generating table layout with VML code that renders correctly in Outlook. We test each template on 5 Outlook versions via Litmus. With over 50% of emails opened on mobile, MJML automatically creates media queries and fluid tables for iPhone 15, Samsung Galaxy, and desktop. Development speed jumps: a typical table-based template takes 3–4 hours by hand; with MJML, it’s 30–40 minutes, reducing error probability.

How we do it

Consider a real case — an electronics online store. The client wanted 4 transactional emails: order confirmation, shipping notification, password reset, and welcome.

Stack: MJML 4.15, Handlebars 2.0, Node.js 20 with TypeScript, mjml CLI compiler, testing in Litmus.

We created a common base using mj-attributes for fonts, colors, and buttons. For each email we wrote an MJML component, splitting into sections: header, content, cta, footer. Dynamic data (name, order number, products) uses Handlebars variables.

Example — order confirmation with a products table. We used <mj-table> for rows so they display correctly in Outlook. The "Track Order" button was made with <mj-button> — it generates VML for Outlook.

After compilation, HTML files ~15 KB each. Backend integration via a Node.js function that takes JSON with order data, substitutes through Handlebars, and returns ready HTML for sending.

Work process

1. Analytics — identify email types, agree on layouts and texts.
2. Design — create prototypes in MJML, show client in test environment.
3. Implementation — code templates, add Handlebars variables.
4. Testing — run through Litmus, fix bugs in Outlook and mobile clients.
5. Deployment — deliver HTML files or Node.js rendering code, write integration documentation.

Estimated timelines

A set of 3-5 transactional templates (order, reset password, welcome) — 4-6 business days. Complex templates with custom animation or AMP for email — up to 8 days.

What's included in the work

• MJML source files (components)
• Compiled HTML files
• Handlebars templates for your backend
• Integration instructions for SendGrid, Amazon SES, or any SMTP
• Litmus testing report with screenshots
• Guarantee of correct rendering in Outlook, Gmail, Apple Mail
• 14-day support after delivery

Why MJML is better than manual table layout

How to test templates across all email clients

We use services like Litmus or Email on Acid — they take screenshots in real clients. For quick local testing — MJML Preview extension for VS Code or mjml -w command for auto-rebuild. For functional testing — sending to a test inbox via Mailtrap.

Tested clients

Contact us to evaluate your project. With 5 years of experience and over 50 delivered projects, we'll prepare a proposal in 1 day — with stack selection and timelines. Order turnkey development starting at $500 per template set and get responsive templates guaranteed to work in Outlook. Get a free consultation on your templates.

Email Campaign Integration: Why Does It Often Break?

We’ve observed that a trigger email sent 10 minutes after registration converts 4–5 times better than the same email sent after 24 hours. This isn’t a marketing myth—it’s mechanics: while the user is still warm, while they remember the context. But most integrations with email services are built like this: form submits → synchronous HTTP request to API → if the API is slow, the user waits 3 seconds → the email either goes out or doesn’t, nobody knows. In one project, we saw a 30% drop in conversion simply because the email service responded with 504 and Laravel’s queue driver wasn’t configured. Lost emails often hit customers silently – no log, no alert, just a missing order confirmation.

If you’re facing lost emails or spam folder issues, order an audit of your current integration – we’ll find bottlenecks within 2 days.

Providers and Their APIs

Unisender — a Russian provider popular in the SMB segment. REST API, simple. Adding a contact: importContacts, sending a transactional email: sendEmail. Important: for transactional emails (order confirmations, password resets), Unisender Go is a separate service with a different API and separate pricing. Mixing bulk and transactional mailings in one stream is bad for domain reputation. Unisender Go handles up to 1000 requests per second.

SendPulse — provides email, SMS, web push, Viber, and Telegram bots through a unified API. Convenient for projects requiring an omnichannel approach. Automation 360 is a visual chain builder; you can trigger automation via API events. The PHP SDK (sendpulse/rest-api-php-sdk) is maintained but updated irregularly – better to use Guzzle directly.

Mailchimp — a choice for international audiences and marketing teams accustomed to the Mailchimp ecosystem. Transactional email via Mandrill (a subsidiary service). Marketing API v3 for list, tag, and campaign management. Webhooks for opens, clicks, unsubscribes, bounces.

SMS. For Russia: SMSCenter, MTS Exolve, Devino Telecom, SMS Aero. Their APIs are similar: a send method with phone, message, sender parameters (sender name must be registered separately with the operator). One nuance: the sender name must be registered through the aggregator with a contract – otherwise SMS won’t be sent on MTS/MegaFon/Beeline networks.

How to Build an Integration That Doesn’t Lose Emails?

Separate Transactional and Marketing Streams

Transactional emails (order confirmations, password resets, delivery status) go through a dedicated sender domain or subdomain tx.example.com. Marketing campaigns go through mail.example.com or news.example.com. If a marketing campaign receives many spam complaints, it should not affect the reputation of the transactional stream. According to SendGrid documentation, transactional messages should be sent through a dedicated IP pool to prevent cross-contamination.

Queue and Retry

Any call to the email API goes through a queue (Laravel Queue, Bull, Celery). If Unisender returns a 503, the job retries after 5 minutes, then 15, then 60. After 5 failed attempts, it goes to a dead letter queue with an alert. The user already received their 200 OK and knows nothing about the issue. This approach reduces bounce rate on projects to 0.5%.

Example Laravel job:

public function handle(): void
{
    try {
        $response = Http::post(config('services.unisender.email_url'), $this->params);
        if ($response->failed()) {
            $this->release(300); // retry after 5 min
        }
    } catch (\Throwable $e) {
        $this->release(300);
    }
}

Templates

We store templates in code (Blade, Twig, React Email), not in the provider’s interface. Reasons: versioning via Git, browser preview without sending, testability. For complex templates with dynamic content — react-email with export to HTML via @react-email/render.

Validation and Consent

Before adding a contact to a list — double opt-in (confirmation email). Store the confirmation timestamp in your own database. Upon unsubscription — synchronously unsubscribe both at the provider and in your database. Ignoring webhook unsubscriptions is a direct path to account suspension at the provider. All processes comply with Федеральный закон № 152-ФЗ «О персональных данных».

Deliverability Monitoring and DKIM Setup

Connect provider webhooks for events: bounce (hard and soft), spam_complaint, unsubscribe. Hard bounce — immediately mark the email as invalid in your database, stop sending. Soft bounce 3 times in a row — same. Metrics: open rate, click rate, bounce rate, unsubscribe rate — review at least once a week. Our certified engineers configure alerts in Grafana/Prometheus.

DKIM configuration steps:

1. Generate a key pair (e.g., openssl genrsa -out private.key 2048).
2. Publish the public key in DNS as a TXT record for the selector (e.g., mail._domainkey.tx.example.com).
3. Provide the selector to the provider (SendGrid, Mailgun, Unisender).
4. Verify with dig TXT mail._domainkey.tx.example.com.

SPF, DKIM, DMARC must be configured separately for each stream. We use subdomains with different DNS records.

Why Is It Important to Separate Streams?

If you send a marketing campaign from the same domain as transactional emails and receive spam complaints, you risk getting the domain blocked — and users will stop receiving even order confirmations. SPF, DKIM, DMARC (Sender Policy Framework, DomainKeys Identified Mail, Domain‑based Message Authentication, Reporting and Conformance) must be configured separately for each stream. In one project, a marketing blast with 12% spam complaints blocked the transactional domain for 48 hours — we had to re‑authenticate with Google and Yandex.

What Does the Integration Scope Include?

• Audit of current communication streams and domain reputation (SPF, DKIM, DMARC)
• Provider and schema selection: transactional vs marketing traffic
• Configuration of SPF, DKIM, DMARC DNS records
• Development of email templates (HTML + dynamic content)
• Backend integration via queues and API
• Webhook setup for deliverability and complaints
• Operations documentation and team training
• Deliverability guarantee and post‑launch support

We deliver production‑ready documentation, access to monitoring dashboards, and a handover session with your engineers. Our certified engineers provide a 30‑day post‑launch health check guarantee.

Timelines and Cost

Cost is calculated individually after audit. We provide turnkey service: from analysis to production monitoring. Contact us for a free engineer consultation — we’ll evaluate your project and give accurate timelines. Over 7 years of experience in email service integration, 50+ projects implemented. Order a free audit of your current integration and receive a report with recommendations and estimated savings.