Choosing the Right Template Engine for Your Emails

Picking the right template engine can make or break your email development workflow. Here's a practical comparison of the engines supported by @nestjs-modules/mailer.

Handlebars

The most popular choice. Handlebars keeps logic out of templates and is easy to learn.

pnpm add @nestjs-modules/mailer-handlebars-adapter handlebars

import { HandlebarsAdapter } from '@nestjs-modules/mailer/adapters/handlebars.adapter';

MailerModule.forRoot({
  template: {
    dir: join(__dirname, 'templates'),
    adapter: new HandlebarsAdapter(),
    options: { strict: true },
  },
});

Best for: Most projects. Simple syntax, great community support, and partials/layouts work well for email structures.

Pug

Pug's indentation-based syntax produces clean, readable templates with less markup.

pnpm add @nestjs-modules/mailer-pug-adapter pug

import { PugAdapter } from '@nestjs-modules/mailer/adapters/pug.adapter';

MailerModule.forRoot({
  template: {
    dir: join(__dirname, 'templates'),
    adapter: new PugAdapter(),
  },
});

Best for: Teams that prefer concise markup and are already familiar with Pug from web projects.

EJS

EJS uses plain JavaScript inside templates, giving you full control without learning a new syntax.

pnpm add @nestjs-modules/mailer-ejs-adapter ejs

import { EjsAdapter } from '@nestjs-modules/mailer/adapters/ejs.adapter';

MailerModule.forRoot({
  template: {
    dir: join(__dirname, 'templates'),
    adapter: new EjsAdapter(),
  },
});

Best for: Developers who want to use plain JavaScript expressions in templates without learning a DSL.

MJML

MJML is purpose-built for responsive emails. It compiles to battle-tested HTML that works across all email clients.

pnpm add mjml

Best for: Production email systems where cross-client rendering is critical. MJML handles the responsive email quirks so you don't have to.

Quick Comparison

Engine	Syntax	Learning Curve	Responsive Emails	Use Case
Handlebars	Mustache	Low	Manual	General purpose
Pug	Indentation	Medium	Manual	Clean markup
EJS	JS inline	Low	Manual	JS-native templates
MJML	XML tags	Medium	Built-in	Production emails

Recommendation

Start with Handlebars if you're unsure. It covers most use cases, has the most examples in the community, and integrates cleanly with layouts and partials.

If you're building marketing or transactional emails that must look perfect across Gmail, Outlook, and Apple Mail, consider adding MJML.

Check the Adapters docs for detailed setup instructions.