What is Spectra plugin?
Spectra (formerly Ultimate Addons for Gutenberg) is a Gutenberg block plugin developed by Brainstorm Force, the team behind the Astra theme and Starter Templates. It extends the native WordPress block editor with over 30 free, customizable blocks without replacing the editor itself — which is the key distinction from traditional drag-and-drop page builders.
Spectra ships with blocks for containers, headings, info boxes, buttons, forms, star ratings, testimonials, tables of contents, and more. The plugin also includes a coming soon mode, a popup builder, and page-level editing features that go beyond what most Gutenberg block add-ons provide in the free tier. Over one million active installations make it one of the most widely deployed block plugins in the WordPress ecosystem.
Because Spectra is built by the same team as Astra, it integrates cleanly with that theme and with Starter Templates, which gives you a fast path from blank site to a working design using the block editor. It also works with other themes. Spectra Pro adds features like loop builder, off-canvas menus, additional blocks, and deeper styling controls.
Spectra is a strong choice when you want to extend the WordPress block editor with design and layout tools while staying close to native WordPress workflows. Teams already using Astra or the Brainstorm Force ecosystem will find the integration natural. If you want a heavier visual builder with more hand-holding, plugins like Elementor or Kadence Blocks may feel more complete out of the box.
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Get Spectra Expert HelpKey Features
- 30+ free Gutenberg blocks
- Container block with flexbox controls
- Coming soon and maintenance mode
- Popup builder (free)
- Forms block for contact and lead capture
Pros & Cons
Pros
- Very generous free tier including popups and coming soon mode
- Over 1 million active installs with a stable development track
- Close integration with Astra theme and Starter Templates
Cons
- Tightly coupled to the Brainstorm Force ecosystem in practice
- Loop builder and some advanced blocks are Pro-only
Free vs Premium
The free plugin covers most common use cases including layout blocks, forms, popups, and coming soon mode. Spectra Pro adds the loop builder, additional advanced blocks, off-canvas navigation, and deeper styling controls. If you are on the Astra theme with a paid plan, some Pro features may already be bundled.
Common Problems & Fixes
Why are Spectra blocks not rendering correctly on the front end?
Spectra loads block-specific CSS and JavaScript dynamically. If a caching or optimization plugin is combining or deferring those assets, blocks can lose their styles or interactive behavior. Try clearing all caches, temporarily disabling optimization plugins, and testing with a default theme. The Spectra settings panel also includes a CSS regeneration option that can fix corrupted style caches.
Why is the Spectra popup not showing or triggering incorrectly?
Popup display issues are usually caused by conflict with another popup plugin, a JavaScript error from an optimization plugin deferring scripts, or incorrect trigger settings in the popup configuration. Check the browser console for JS errors first. If optimization is the issue, exclude Spectra scripts from delay or combine settings. Also verify that cookies or session conditions are not preventing the popup from firing for returning visitors.
Why is Spectra showing a blank editor or failing to load blocks in the Gutenberg editor?
Editor failures with Spectra are most commonly caused by a JavaScript conflict with another plugin or theme, insufficient PHP memory, or an outdated version of WordPress or Spectra itself. Test by switching to a default theme, deactivating other plugins one at a time, and checking the browser console for the specific error. The Spectra team maintains an active support forum at wordpress.org and a detailed troubleshooting guide in their knowledge base.
Customization & Developer Notes
How do I disable individual Spectra blocks I am not using?
Spectra includes a block management screen at Spectra → Settings → Blocks. You can toggle individual blocks off to prevent their assets from loading on pages where they are not used. This is one of the more practical performance features in the free plugin and is worth configuring if you only use a subset of the available blocks.
Can I add custom CSS to Spectra blocks?
Yes. Each Spectra block has an Advanced tab in the block settings panel where you can add custom CSS classes. You then write the corresponding styles in your theme, child theme, or a code snippet plugin. Spectra Pro also adds additional styling controls within the editor itself for more granular customization without leaving the block panel.
Frequently Asked Questions
Does Spectra work with themes other than Astra?
Yes. Spectra is designed to work with any WordPress theme. The integration is deepest with Astra because both products share the same development team, but the blocks function independently of the theme.
What is the difference between Spectra and Kadence Blocks?
Both are Gutenberg block plugins with generous free tiers. Spectra integrates most naturally with the Astra and Brainstorm Force ecosystem, includes a free popup builder, and has a strong Starter Templates connection. Kadence Blocks has a more developed advanced form builder, a broader free block selection, and integrates with the Kadence theme. The best choice depends on which theme ecosystem you are already using.
Is Spectra the same as Ultimate Addons for Gutenberg?
Yes. Spectra is the rebranded version of Ultimate Addons for Gutenberg (UAG). The plugin was renamed to Spectra in 2022. Existing installations update seamlessly and the plugin slug on WordPress.org remains ultimate-addons-for-gutenberg.
Does Spectra include a form builder in the free version?
Yes. Spectra includes a Forms block in the free version that covers contact forms, newsletter forms, and suggestion forms. It handles basic form needs without requiring a separate form plugin, though dedicated form plugins like Fluent Forms or WPForms offer more conditional logic, more integrations, and better spam protection for complex requirements.