Why Email Templating Is Still Painful in 2026
Web development has come a long way. We have component-driven frameworks, utility CSS, design systems, hot module replacement. Then you open an email template and it is 800 lines of nested tables with inline styles targeting Outlook 2007. The gap between building a modern web page and building a production email is enormous, and it has barely narrowed in 20 years.
The root cause is email clients. Gmail strips <style> tags in certain contexts. Outlook on Windows uses Microsoft Word's rendering engine (yes, Word) to display HTML. Apple Mail is the most standards-compliant, but you cannot assume your users are on Apple Mail. Yahoo Mail, Samsung Email, and dozens of obscure clients each have their own quirks. There is no universal standard. You are building for the lowest common denominator, and that denominator is low.
Three frameworks have emerged as the serious contenders for solving this problem: React Email (JSX components with TypeScript), Maizzle (Tailwind CSS for email), and MJML (XML-based responsive markup). Each takes a fundamentally different approach. If you have already chosen your transactional email provider, the next decision is how you will build the templates those providers send.
React Email: JSX Components for Email
React Email takes the most opinionated stance of the three: your email templates should be React components. If your team already writes React (and most frontend teams do), this means email templates use the same language, the same tooling, and the same mental model as the rest of your codebase. No context switching between JSX and some proprietary template syntax.
How It Works
You install @react-email/components and build templates using pre-built components like <Html>, <Head>, <Body>, <Container>, <Section>, <Text>, <Button>, <Img>, and <Link>. Each component outputs the ugly table-based HTML that email clients require, but you never touch that HTML directly. You write clean JSX, and React Email handles the cross-client rendering under the hood.
The preview server is a standout feature. Run npx react-email dev and you get a local web app that renders every template in your project with hot reload. Change a prop, see the result instantly. This alone saves hours compared to the traditional email workflow of "edit HTML, send test email, open on phone, repeat."
TypeScript Support
Full TypeScript support means your template props are type-checked. If your welcome email expects userName: string and activationUrl: string, the compiler will catch it when you forget a required prop. This matters when multiple developers are editing templates across a growing product.
Strengths
- Component reusability: Build a
<Header>component once, use it in every template. Change the logo or brand color in one place. - Conditional rendering: Use standard React patterns for conditional content. Show different CTAs for free vs. paid users. Render localized content based on language props.
- Ecosystem integration: Works with any email provider. Resend built React Email, but you can render templates to HTML strings and send them through SendGrid, Postmark, Amazon SES, or any SMTP server.
- Testing: Render templates in unit tests, snapshot test the output HTML, and catch regressions before deployment.
Limitations
React Email requires a Node.js build step. If your backend is Python, Go, or PHP, you need a separate Node process or a build pipeline that pre-renders templates to HTML. The component library, while growing, does not cover every edge case. Complex layouts sometimes require dropping down to raw HTML tables. The framework is still relatively young (first stable release in 2023), so you will occasionally encounter components that do not render perfectly in Outlook on Windows.
Maizzle: Tailwind CSS Meets Email
Maizzle takes a different philosophy. Instead of abstracting away email HTML with components, it gives you a powerful build system that transforms Tailwind CSS utility classes into email-safe inline styles. If you know Tailwind, you already know how to use Maizzle. The learning curve is nearly zero for teams that have adopted utility-first CSS.
The Build Pipeline
Maizzle uses a multi-step build process. You write HTML (or Nunjucks/Handlebars templates) using Tailwind classes. The build system compiles Tailwind, inlines the CSS, removes unused styles, minifies the output, applies email-specific transformations (like converting width classes to HTML width attributes), and produces production-ready HTML files. The entire pipeline is configurable through a config.js file.
This build-centric approach means Maizzle produces the most optimized output of the three frameworks. The generated HTML is compact, every style is inlined, and unused CSS is purged. For email, file size matters because Gmail clips messages larger than 102 KB.
Template System
Maizzle supports layouts, components, and partials out of the box. Define a base layout with your header, footer, and brand styles, then extend it in individual templates. Components work similarly to web components, letting you create reusable blocks like buttons, cards, and dividers. The template engine supports expressions, conditionals, loops, and data from JSON or front matter.
Strengths
- Tailwind familiarity: No new syntax to learn. Use the same utility classes your team uses on the web. The email-specific Tailwind config handles the differences (MSO conditionals, VML for Outlook backgrounds).
- Build optimization: The output is the leanest HTML of any framework. CSS inlining, purging, and minification happen automatically.
- Framework-agnostic: Maizzle produces static HTML files. Use them with any backend language or email provider. No runtime dependency.
- Customizable transformations: Need to add a specific Outlook conditional comment, convert hex colors for dark mode, or apply custom post-processing? The build pipeline is fully extensible through PostHTML plugins.
Limitations
Maizzle's templating is based on HTML, not JSX. If your team writes React, you will be context-switching between component syntax and HTML template syntax. There is no live preview server with hot reload comparable to React Email's. You can use browsersync for auto-refresh, but it is not the same tight feedback loop. Dynamic data injection (like a user's name or order total) requires integration with your email provider's template variables, which means the templates you preview locally look different from what gets sent.
MJML: The XML Standard for Responsive Email
MJML (Mailjet Markup Language) was created by Mailjet in 2015 and has become the most widely adopted email framework. Its approach is declarative: you write XML-like markup using custom elements, and MJML compiles it to responsive, cross-client HTML. The philosophy is that email has its own constraints, so it deserves its own markup language rather than shoehorning web tools into email.
Responsive by Default
This is MJML's killer feature. Every <mj-section> and <mj-column> is responsive by default. A two-column layout on desktop automatically stacks to single-column on mobile. You do not write media queries. You do not test breakpoints. The compiled output includes all the necessary responsive CSS and table structures. For teams that need reliable responsive emails across every client, MJML delivers this with minimal effort.
The Component Model
MJML provides high-level components: <mj-button>, <mj-image>, <mj-social>, <mj-navbar>, <mj-hero>, <mj-carousel>. Each compiles to the correct table-based HTML for cross-client compatibility. You can also create custom components, though the API for doing so is more complex than React Email's component model.
Strengths
- Battle-tested: 10+ years of production use. Millions of templates built with MJML. The compiled output has been tested against every major email client.
- Responsive without effort: The grid system handles responsive layouts automatically. Two columns become one column on mobile without you writing a single media query.
- Language-agnostic: MJML has compilers in JavaScript (official), Python, PHP, Ruby, and Java. Your backend language almost certainly has an MJML library.
- Ecosystem: VSCode extensions, online editors, Figma plugins, and integrations with most email platforms. The tooling ecosystem is the most mature of the three.
Limitations
MJML's XML syntax feels verbose compared to JSX or Tailwind classes. A simple button requires <mj-button font-family="Helvetica" background-color="#3B82F6" color="white" font-size="16px" padding="12px 24px">. If you are building 30 templates, that repetition adds up. Custom components require writing a JavaScript class that extends MJML's core, which is significantly more work than creating a React component or a Maizzle partial. MJML 5 is in development and promises a simpler custom component API, but it has been in beta for a while.
Cross-Client Rendering and Dark Mode
Choosing a framework is only half the battle. The real test is whether your emails look correct in Outlook 2019, Gmail on Android, Apple Mail on iOS, Yahoo Mail on the web, and the Samsung Email app that ships on Galaxy devices. Each client interprets HTML and CSS differently, and dark mode adds another layer of unpredictability.
The Outlook Problem
Outlook on Windows (the desktop app, not Outlook.com) uses Microsoft Word's HTML renderer. This means no support for flexbox, grid, CSS variables, or many modern CSS properties. Backgrounds on table cells behave differently. Padding is inconsistent. VML (Vector Markup Language) is required for background images. All three frameworks handle Outlook to varying degrees, but none of them fully abstract away the pain.
React Email's Outlook support has improved significantly since 2024, but complex layouts still require MSO conditional comments in some cases. Maizzle provides explicit Outlook utilities and MSO conditional helpers in its Tailwind config. MJML handles Outlook the best out of the box because its compiler has 10 years of Outlook-specific rendering logic baked in.
Gmail Quirks
Gmail strips embedded <style> tags when the HTML exceeds certain thresholds or when email is forwarded. All three frameworks inline CSS as their primary strategy, which sidesteps this issue. Gmail also does not support media queries in all contexts, making the responsive behavior framework-dependent. MJML's approach to responsive email is the most resilient here because it uses a combination of table widths and inline styles rather than relying on media queries alone.
Dark Mode
Dark mode in email is a mess. Apple Mail inverts colors predictably using the prefers-color-scheme media query. Gmail on Android and iOS partially supports dark mode by auto-inverting light backgrounds to dark ones, but the algorithm is unpredictable. Outlook.com applies its own dark mode transformations that can turn your carefully designed template into an unreadable mess.
React Email supports dark mode through its <Head> component, where you can include dark mode CSS. Maizzle has first-class dark mode support through its Tailwind config, with dark: variants that compile to the correct media queries and MSO-specific overrides. MJML requires manual <mj-style> blocks for dark mode, which works but is not as ergonomic. The practical advice: design emails that look acceptable when colors are auto-inverted, use high-contrast text, and avoid transparent PNGs on colored backgrounds (they look terrible when the background is inverted).
Testing Tools
Regardless of which framework you choose, test with Litmus or Email on Acid. These services render your email across 90+ client and device combinations and show you exactly what breaks. Budget $100 to $150 per month for a team plan. The alternative is manually testing on dozens of devices, which no one actually does consistently.
CI/CD Integration and Template Reusability
Email templates are code. They should live in your repository, go through code review, pass automated checks, and deploy through your pipeline. All three frameworks support this, but the integration story varies.
React Email in CI/CD
React Email templates are TypeScript files. They get linted, type-checked, and tested alongside the rest of your codebase. You can write unit tests that render a template with specific props and assert on the output HTML. Snapshot tests catch unintended changes. In your CI/CD pipeline, add a step that renders all templates and optionally uploads them to your email provider's template store via API.
For teams using Resend, the workflow is seamless: templates render at send time, so there is no separate deployment step. For other providers, you add a build step that renders templates to HTML and uploads them. This is straightforward but requires a Node.js environment in your pipeline.
Maizzle in CI/CD
Maizzle's build command (maizzle build production) outputs static HTML files. Add this to your pipeline as a build step, then upload the HTML files to your provider or copy them to a shared template repository. Because the output is plain HTML, there are no runtime dependencies. The build is fast (usually under 5 seconds for 30 templates) and the output is deterministic.
Maizzle also supports multiple build environments (development, staging, production) with different configurations. You can have a development build that keeps comments and skips minification, and a production build that strips everything for minimum file size.
MJML in CI/CD
MJML compiles XML to HTML via a CLI command (mjml input.mjml -o output.html) or programmatically through the JavaScript API. Add a compile step to your pipeline, run it across all templates, and upload the output. MJML also has a validation mode that checks your markup for errors without compiling, which is useful as a pre-commit hook or CI gate.
Template Reusability Across Projects
If your organization has multiple products that share brand elements (logo, colors, footer, legal text), template reusability becomes critical. React Email handles this best because components are just JavaScript modules. Publish a shared package (@yourcompany/email-components) to your private npm registry, and every product imports the same header, footer, and brand components. Maizzle supports this through its components and a shared config, but it requires more manual setup. MJML supports includes and custom components, but distributing shared MJML components across projects is the least ergonomic of the three.
Migrating from Legacy HTML Templates
Most teams are not starting from scratch. You probably have a folder of hand-coded HTML email templates, maybe built years ago by a contractor, that work "well enough" but are a nightmare to update. Migrating to a modern framework is worth the investment, but you need a practical strategy.
The Incremental Approach
Do not try to rewrite every template at once. Pick your highest-volume email (probably a transactional notification or welcome email) and rebuild it in your chosen framework. Deploy it, monitor deliverability and rendering, and confirm everything works. Then migrate the next template. This approach lets you catch framework-specific issues early without risking your entire email infrastructure.
Migrating to React Email
Start by identifying the common elements across your existing templates: header, footer, button styles, typography. Build those as React components first. Then convert each template by replacing table-based layouts with React Email components. The hardest part is usually the Outlook-specific conditional comments. React Email handles most of them, but you may need to keep some manual <!--[if mso]> blocks for edge cases.
Migrating to Maizzle
Maizzle has a gentler migration path because it works with raw HTML. You can drop your existing HTML templates into a Maizzle project, and the build system will inline CSS and optimize them without rewriting the markup. Then gradually replace inline styles with Tailwind classes and extract reusable components. This "wrap and improve" approach means your templates keep working throughout the migration.
Migrating to MJML
MJML requires the most rewriting because the markup is completely different from standard HTML. You cannot drop existing HTML into an MJML file. Every element needs to be converted to MJML's component syntax. The upside is that the resulting templates are cleaner and more maintainable. For teams with many templates, consider using MJML's online converter tool as a starting point, then clean up the output manually.
Which Framework Fits Your Team
If your team writes React daily and values type safety, React Email is the natural choice. The learning curve is minimal, and the component model scales well. If your team uses Tailwind CSS and wants the most optimized output with a framework-agnostic build, Maizzle is excellent. If you need the most battle-tested cross-client rendering with the least custom debugging, MJML is the safest bet. All three are actively maintained, well-documented, and production-ready.
For teams building AI-powered email workflows, all three frameworks work well as the template layer. The framework renders the HTML, and your AI system populates the dynamic content. The key is keeping your template layer clean and your content layer flexible.
If you are unsure which framework fits your team, or you need help migrating from legacy templates and integrating email into your CI/CD pipeline, we have done this for dozens of startups. Book a free strategy call and we will map out the right approach for your stack and volume.
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