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What SuiteCommerce Fallback Themes Are & How to Implement Them

A fallback theme in SuiteCommerce/SuiteCommerce Advanced (SCA) is a lightweight custom theme that overrides only the files you change; everything else “falls back” to the base theme. It allows you to customize only the necessary files — like templates, styles, or assets — while the rest is handled by the base theme.

Introduced in release 2023.2, this architecture slashes maintenance, speeds deployments, and keeps you compatible with NetSuite updates. Below you’ll find the requirements checklist, step-by-step setup, common pitfalls, and tips for keeping your storefront lean.

What Fallback Themes Are and How to Implement

Table of Contents

1. Why NetSuite Added Fallback Themes

Before 2023.2, a custom theme copied every template, stylesheet, and asset from the base theme. Even a minor color tweak forced you to own the full codebase, making upgrades painful. NetSuite’s new fallback architecture solves that by letting your theme inherit unchanged files automatically—similar to class inheritance in software development. Oracle’s release notes highlight the goal: easier upgrades and less risk when the base theme evolves.

The business pain it solves

  • Update paralysis – Teams often delayed adopting new SuiteCommerce versions because retrofitting changes into a heavily customized theme felt too risky.
  • Bloated repos – Re-uploading hundreds of untouched files clogged Git histories and DevTools workspaces.
  • Slow first paint – Larger theme packages marginally increased deployment and activation time, especially on sites with multiple domains.

Fallback themes tackle each issue by letting you touch only what matters.

2. What Exactly Is a Fallback Theme?

NetSuite’s developer portal defines a fallback theme as a “custom theme that inherits all files from the base theme except the ones you override”. In practice, that means:

  1. The system first looks for the requested template, CSS, or asset within the currently active theme.
  2. If it’s not found there, it continues the search in the fallback theme (the base theme).
  3. The first available version version of the file is used, so the page renders either your custom version or the default.

Because the base theme ships with every SuiteCommerce release, you always have a complete set of templates, Sass, and JavaScript ready to backstop your changes.

3. Benefits You’ll Notice on Day One

Benefit Why it matters
Less maintenance You only patch files you changed, so future NetSuite upgrades are smoother.
Update independence Allows you to update SuiteCommerce Base Theme to the latest version without any risk.
Quicker deployments Smaller theme bundles upload and activate faster, which is noticeable on multi-domain sites.
Cleaner repos Engineers can find real customizations at a glance rather than sifting through boilerplate.
Oracle’s own documentation notes that bug fixes and small improvements “should be seamlessly delivered and integrated into your custom theme” under this model.

4. What You Can—and Can’t—Change

Green lights

You can only modify:
  • Existing templates (.tpl)
  • Existing Sass / CSS modules
  • Existing JavaScript modules

Red lights

  • Brand-new files – The fallback mechanism can’t see files that don’t exist in the base theme.
  • Partial asset folders – If you override /assets/img, you must manage the entire folder hierarchy — not just individual files.
  • One-click migration – Migration from custom themes is manual. Switching from a fully unmanaged theme to a fallback one requires creating a new theme and migrating changes incrementally.

5. Version & Tooling Checklist

Requirement Minimum version
SuiteCommerce / SCA 2023.2
Theme Developer Tools v23.2.x
SuiteCommerce Base Theme v23.2.x or later installed and activated on the domain

The version of dev tools cannot be higher than the version of the base theme installed and activated.

Confirm you’re on compatible versions before you start; mismatches will throw manifest.json validation errors.

6. Setting Up Your First Fallback Theme

Follow this quick-start, then scroll for the “why” behind each step.

Step Command or action Purpose
1. Install DevTools npm install -g @oracle/suitecloud-theme-tools@23.2 Make sure you’re using the latest compatible version.
2. Install Dependencies npm install Install the project dependencies.
3. Create the custom theme Ensure "sub_type": "fallback" This is very similar to creating an extension — the steps are almost identical.
4. Check the manifest Ensure "sub_type": "fallback" After creating the custom theme, the manifest.json file includes a property called "sub_type" set to "fallback", indicating that the theme uses fallback functionality.
5. Run new theme locally First run pulls down the base theme to /Extras. On the first run, this will download the base theme to the extras folder, similar to an extension fetch of the theme.
6. Start customizing Copy-edit only the files you truly need. After all these steps we can start with the customizations.

Under the hood, DevTools stores the base theme in an Extras directory so you can diff against originals without leaving your IDE.

7. Customizing Without Breaking the Chain

a) Mirror the path – If you plan to override /Templates/ProfileEdit.tpl, replicate that exact folder structure inside your theme.

  • To start customizing a SASS file or a template, we need to copy the same folder structure that is in the base theme.
  • The base theme is located in the Extras folder, inside the Extensions folder, sharing the folder with the other extensions.
Mirror the path - Fallback Themes

b) Copy once, then tweak – After copying the same folder structure for the file you want to customize, copy the file itself and paste it into that folder.

Copy once, then tweak - Fallback Themes

Restart local server – If the project is running locally, press CTRL+C to stop the terminal, and then run it again so the new file can be reflected in the manifest.json

c) Smoke-test – Now you can check your updates locally. If everything looks correct, we can proceed with the deployment.

In the Extension Manager, you will see the theme displayed like this (screenshot above) when it’s time to activate it.
Smoke-test - Fallback Themes

8. Migrating an Existing Custom Theme

Moving from an older, fully managed theme to fallback architecture is a project in itself:

  1. Create a fresh fallback theme rather than trying to retrofit.
  2. Port changes incrementally, starting with global Sass variables and header templates.
  3. Delete unused overrides—if the base theme now meets your needs, don’t copy the file.
  4. Use Git history to ensure critical tweaks aren’t lost.
  5. Run side-by-side browser tests on staging domains before going live.

Because migration is manual, allocate enough QA time and involve both dev and design stakeholders early.

Dive deeper

Want to learn more? Check out our previous posts:

The Payoff: Easier Upgrades, Happier Teams

Once you’re live on a fallback theme, adopting the next SuiteCommerce release becomes a routine CLI upgrade rather than a week-long merge marathon. Your designers stay nimble, your engineers focus on value-add features, and your site benefits from Oracle’s ongoing accessibility, performance, and bug-fix updates—all with minimal overhead.

Key Takeaways

  • Fallback themes = selective overrides + base inheritance.
  • Introduced in SuiteCommerce 2023.2, supported via DevTools v23.2.
  • Best for teams who value agility and future-proofing.
  • Pair with helper extensions when you need configurable UI logic.
  • Migrate gradually—don’t copy more than you must.

Implement these practices and you’ll spend less time wrestling with upgrades and more time crafting experiences your shoppers notice.

Have a question about fallback themes or want to see a live demo? Let’s talk!

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