Handlebars vs Nunjucks vs Pug for Static HTML Builds

What These Engines Actually Do

HTML templating engines let you write layouts once and inject content, variables, or reusable chunks at build time, producing plain static HTML files as output. The resulting files need no server runtime, load instantly from a CDN, and require no JavaScript framework on the client. That makes them a practical middle ground between raw copy-paste HTML and a full static-site generator like Next.js or Astro.

All three engines covered here run in Node.js and can be driven by Gulp tasks, Eleventy data pipelines, or a custom Vite plugin. The difference is in what each language lets you express inside a template file.

If you want context on how this fits into a broader Bootstrap 5 build pipeline, the post on setting up Vite for a Bootstrap 5 HTML template build covers the bundler side of that equation.

Handlebars: Logic-Less and Deliberate

Handlebars (current stable: 4.7.x) is based on Mustache and deliberately restricts what you can do inside a template. There are no arbitrary expressions, no arithmetic operators, and no direct property access beyond simple dot notation. Any non-trivial logic must live in a registered helper function written in JavaScript.

<!-- Handlebars partial registration -->
<!-- helpers.js -->
Handlebars.registerHelper('uppercase', (str) => str.toUpperCase());

<!-- template.hbs -->
<h1>{{uppercase title}}</h1>
{{> card-partial card}}

Where Handlebars wins: It enforces a clean separation between data and presentation. Designers can edit templates without accidentally introducing business logic. Helper functions are unit-testable. The syntax is minimal and readable by non-developers.

Where Handlebars loses: Anything beyond simple loops and conditionals requires a custom helper. Template inheritance is not built in. You can simulate layouts with a {{> body}} pattern, but it is clunky compared to block-level inheritance. For a multi-page Bootstrap 5 project with a shared header, footer, sidebar, and per-page hero variations, Handlebars generates a lot of helper boilerplate that Nunjucks handles natively.

Avoid Handlebars when your templates need filters, complex conditionals, or layout blocks that vary per page. Also avoid it if your team is already familiar with Jinja2 from a Python background.

Nunjucks: Full-Featured and Jinja2-Compatible

Nunjucks is maintained by Mozilla and is currently at version 3.2.x. It is a near-complete JavaScript implementation of Jinja2, which means developers coming from Django, Flask, or Twig will feel at home immediately.

<!-- base.njk -->
<!DOCTYPE html>
<html lang="en">
<head>
  <title>{{ pageTitle }} | Canvas</title>
</head>
<body>
  {% include "partials/header.njk" %}
  {% block content %}{% endblock %}
  {% include "partials/footer.njk" %}
</body>
</html>

<!-- about.njk -->
{% extends "base.njk" %}
{% set pageTitle = "About Us" %}

{% block content %}
<section class="section">
  <div class="container">
    <h1>{{ pageTitle }}</h1>
    {% for item in features %}
      <p>{{ item.label | upper }}</p>
    {% endfor %}
  </div>
</section>
{% endblock %}

Key Nunjucks features relevant to static site templating:

• Template inheritance via {% extends %} and {% block %}, which lets every page share a base layout without duplication.
• Macros that behave like reusable functions with arguments, ideal for generating Bootstrap card markup from a data object.
• Built-in filters including upper, truncate, replace, groupby, and sort, so most formatting logic stays in the template rather than a helper file.
• Async rendering support for fetching data at build time.

For a practical walkthrough of how this works with a multi-page HTML template, see splitting a large HTML template into reusable partials with Nunjucks.

Where Nunjucks loses: The Nunjucks npm package has seen infrequent releases recently, and some teams flag this as a long-term maintenance concern. Template error messages are sometimes vague, which slows debugging when a block name is misspelled. Performance on very large builds (thousands of pages) is slower than Pug, though for the typical 10 to 100 page marketing site this is irrelevant.

Pug: Concise Syntax, High Learning Curve

Pug (formerly Jade, current stable: 3.0.x) replaces HTML angle-bracket syntax entirely with indentation and CSS-style selectors. The result is dramatically fewer characters per line, but complete sensitivity to whitespace errors.

//- layout.pug
doctype html
html(lang="en")
  head
    title= pageTitle + ' | Canvas'
  body
    include partials/header
    block content
    include partials/footer

//- about.pug
extends layout

block content
  section.section
    .container
      h1= pageTitle
      each item in features
        p= item.label.toUpperCase()

Where Pug wins: The syntax is extremely compact. Full template inheritance, mixins (the Pug equivalent of macros), inline JavaScript expressions, and filter support are all built in. Build performance is generally faster than Nunjucks on large page counts. Pug also has first-class support in many Express and Nuxt configurations if your project later needs a server component.

Where Pug loses: The non-HTML syntax is a barrier for designers and clients who need to edit templates. Copy-pasting HTML from component libraries, browser DevTools, or a tool like the Canvas HTML Template requires conversion, which adds friction. A stray space or tab breaks the entire render. Code review diffs are harder to read when the syntax is unfamiliar. For agencies handing off projects to in-house marketing teams, this is a practical problem.

Avoid Pug when non-developer stakeholders will edit templates, or when you are integrating pre-built HTML component libraries that ship standard markup.

Side-by-Side Feature Comparison

• Template inheritance: Nunjucks (native), Pug (native), Handlebars (plugin or workaround required).
• Reusable components: All three. Nunjucks macros and Pug mixins accept parameters. Handlebars partials accept a context object.
• Built-in filters: Nunjucks has the richest set. Pug allows inline JS expressions. Handlebars requires registered helpers for everything.
• Syntax familiarity: Handlebars and Nunjucks use HTML with delimiters. Pug uses its own indentation-based language.
• Eleventy compatibility: All three are officially supported Eleventy template languages as of Eleventy 2.x and 3.x.
• Vite/Gulp integration: All three have maintained community plugins. Nunjucks has gulp-nunjucks-render. Pug has vite-plugin-pug. Handlebars has gulp-compile-handlebars.
• Error messages: Pug gives the most precise line and column errors. Nunjucks errors are adequate. Handlebars errors can be cryptic.

Which Engine Fits Bootstrap 5 Template Projects

For teams building or customising a large Bootstrap 5 HTML template with 20 or more pages, shared navigation, hero variants, and reusable card sections, the recommendation is Nunjucks. The {% extends %} and {% block %} system maps directly onto the mental model of “base layout plus per-page overrides,” and macros make it straightforward to generate repeated markup from a JSON data file. The built-in filter library covers the majority of formatting tasks without extra helper files.

Choose Handlebars if your project is content-only (a documentation site or a simple landing page set), you want strict enforced separation between logic and templates, or you are integrating with a CMS that already uses Handlebars (Ghost themes, for example).

Choose Pug if your entire team is comfortable with its syntax, you are building a high page-count project where build speed matters, or you are already inside an Express or Nuxt stack that uses Pug natively.

Whatever engine you choose, pairing it with a solid performance baseline matters. The guide on critical CSS for Bootstrap 5 templates covers how to eliminate render-blocking styles from the static HTML files your templating engine produces.

Migration Considerations

If you start a project in one engine and need to switch, the practical cost varies. Moving from Handlebars to Nunjucks is relatively low effort because both use standard HTML as a base: you are primarily replacing {{variable}} syntax with {{ variable }} and adding block inheritance. Moving to or from Pug is a different matter. Every template file must be converted to or from the indentation syntax, which is a significant one-time investment for anything beyond a small project. Tools like html2jade and the reverse converter pug-to-html exist but require manual review of every output file.

Looking for a production-ready Bootstrap 5 HTML template? Browse Canvas Template demos and find the perfect starting point for your next project.

If you’re building with the Canvas HTML Template and want to ship production-ready Bootstrap 5 layouts faster, try Canvas Builder free — the visual builder that exports clean Canvas-ready markup in minutes.