Generate HTML from MJML for Email Templates

Convert MJML into production-ready responsive HTML with a single API call—fully integrated into your email workflow.

Why MJML?

MJML is the open-source framework that makes responsive email design simple and reliable. But rendering it into robust HTML across all email clients can be tricky. That’s where Outliny comes in. We let you write in MJML and instantly generate HTML optimized for all major email clients—using our fast, scalable, and secure API.

How It Works

  1. Create your MJML template: Use Outliny's drag-and-drop GrapeJS Email Editor or write manually via API.
  2. Send to Outliny API: Pass your MJML and variables to our /generate-html endpoint.
  3. Get responsive, production-ready HTML: Instantly returned, minified, and email-ready.

Example API Usage

POST /api/v1/emails/generate-html
Content-Type: application/json
Authorization: Bearer YOUR_API_KEY

{
  "template_id": "welcome-email",
  "data": {
    "first_name": "Jane",
    "signup_date": "2025-05-01"
  }
}

Response:

{
  "html": "<!DOCTYPE html><html>...rendered responsive email...</html>"
}

Features

  • Supports MJML 4.15+
  • Full Jinja2 support
  • Reusable modules (headers, footers, components)
  • Mobile-first responsive design
  • Open source templates and examples
  • Ready for CRM, HRMS, marketing, and transactional emails

Use Cases

  • CRM and Marketing Automation
  • Internal HR Emails
  • Signup / Welcome Emails
  • Password Reset / OTPs
  • Notifications and Alerts

Security-First

  • No email content is logged
  • Encrypted API communication
  • ISO 27001:2022 & SOC 2 Type II Certified

Export or Import Anytime

You’re never locked in. Outliny supports import/export of MJML and HTML, so you can move templates freely between systems.

Tip for Developers

Use our pre-built email components and themes to speed up development. No need to start from scratch—just customize and deploy.

See the Developer Docs Ask on GitHub