Spectra vs Kadence Blocks: Hands-On Test of the New Plugin Landscape

If you’ve searched for Spectra blocks in 2026, you’ve probably run into a confusing situation: there are now two plugins with nearly the same name. The original Ultimate Addons for Gutenberg was renamed Spectra Legacy and remains in maintenance mode with over a million active installs. Brainstorm Force rebuilt the product from scratch on modern WordPress core block APIs and launched it as a separate plugin called Spectra Blocks. It currently sits at 40,000+ active installs and is where future development is headed.

This hands-on comparison tests Spectra Blocks against Kadence Blocks, not the Legacy plugin. I won’t mix Spectra Legacy’s feature list or installation numbers into the new Spectra product, because the two share almost nothing internally. They don’t even share global colors, typography, or default block settings. Migrating from Legacy to Blocks means a manual, page-by-page rebuild.

Here’s what each contender brings to the test:

Spectra Blocks is completely free on WordPress.org under the exact name “Spectra Blocks – AI Website Builder for the Block Editor.” It requires WordPress 6.6+ and PHP 8.1+, and it uses new spectra/ block markup, which means custom code written for Legacy won’t carry over.

Kadence Blocks is the established option here, with 600,000+ active installations and a 4.8/5 rating. It extends Gutenberg with custom blocks, responsive and design controls, a Design Library, configurable defaults, visibility controls, forms, and galleries. It’s still actively developed.

My approach: I’ll install both plugins on clean WordPress sites, build the same landing page in each, capture screenshots along the way, and judge them on real use rather than a spec sheet. Here’s the scorecard I’ll be filling in:

Category	Spectra	Kadence Blocks	Winner
Ease of use	Test	Test	After testing
Editor experience	Test	Test	After testing
Blocks/features	Compare	Compare	After testing
Design controls	Compare	Compare	After testing
Templates/patterns	Compare	Compare	After testing
Performance	Benchmark	Benchmark	After testing
Responsive controls	Test	Test	After testing
Advanced features	Compare	Compare	After testing
Compatibility	Test	Test	After testing
Value	Current pricing	Current pricing	After testing

Ease of Use and Native Block Editor Experience

I installed both plugins on fresh WordPress 6.6 sites and built the same landing page in each: a hero section, a three-column feature row, a testimonial block, and a call-to-action band. I skipped starter templates and pre-built patterns and used only raw blocks and whatever each plugin gave me. I wanted to see how far the native tools would take me before I had to work around them.

The Spectra Blocks build took roughly 25 minutes. The Container block does most of the work here, and it’s flexible: it can nest any block inside it, including core WordPress blocks and third-party ones, so you’re never locked out of something the plugin doesn’t ship. Spacing, padding, background, and border controls all live in the sidebar where you’d expect them. The friction came mostly from learning where Spectra puts things versus where Gutenberg puts them, which is a short learning curve, not a barrier.

The Kadence Blocks build came in around 20 minutes. The Row Layout block handles the same job as Spectra’s Container, and at least one reviewer I respect has called it superior for complex custom landing pages. I’m inclined to agree after this test. Row Layout gives you column controls that feel more immediate, with visible column-width handles and a clearer way to manage nested structures. Kadence 3.0 also brought a redesigned block settings panel, copy/paste styles, and import/export defaults, all of which cut down on repetitive clicking when you’re building several similar sections.

What stood out was how differently the two approach the editor. In the sidebar you can see Kadence’s controls are grouped into tidy, collapsible panels with clear labels, and the block toolbar stays minimal until you select something. It feels like a more mature version of Gutenberg, not a replacement. Spectra Blocks uses current WordPress core block APIs, and it shows: the block markup and inspector behavior track core closely. But the settings panel gets busier faster, especially once you stack Container options, typography, and responsive toggles in the same view.

Neither editor felt cluttered in a way that slowed me down. Both keep their block toolbars reasonably restrained, and navigation between block settings and page-level settings is straightforward in each. Kadence Blocks feels like a tool that has been refined through years of real-world use, while Spectra Blocks feels like the clean, modern rewrite that’s still discovering which controls deserve top billing.

For now, both plugins let a competent user build a polished page without touching code.

Block Libraries, Design Controls, and Pattern Libraries

Spectra Blocks ships 49 blocks, Kadence Blocks lists somewhere between 20 and 30-plus depending on which source you trust, and neither number tells you much about how fast you’ll actually build a page.

Spectra Blocks takes a deliberately composable approach. Instead of shipping a bespoke block for every conceivable layout, it gives you a smaller set of flexible building pieces and layers advanced controls on top through what it calls Extensions. The Container block is the main block, but the lineup includes Accordion, Tabs, Slider, Post, Countdown, Counter, Modal, and Popup Builder. An FAQ section is just the Accordion block with a few rows filled in. A testimonial or a comparison table gets assembled from Container, Icon, Heading, and Paragraph blocks rather than pulled from a single-purpose widget. That sounds like extra work on paper, but in practice it means you’re never hunting for the one block that almost does what you want. You build it from parts you already understand.

Kadence Blocks takes the opposite route and leans into dedicated blocks, which is why its free version lists 20 blocks per one source and 30-plus per another. The gap between those numbers comes down to what you count and when you checked. Either way, the free tier covers the essentials, and one detail stands out: 1,500-plus SVG icons load without a font-family, so they render fast and never trigger a flash of invisible text. The Pro upgrade adds 10-plus premium blocks along with custom icons, custom fonts, on-scroll animation, and dynamic content, all available only in the paid tier.

The pattern libraries tell a similar story. Kadence promotes a Design Library with hundreds of pre-built patterns, which was the fastest way to a professional-looking page I found in either plugin. Spectra Blocks’ Design Library is more modest, with pre-built patterns for testimonials, info boxes, pricing tables, and comparisons, but it covers the sections that most landing pages actually need. The screenshot I captured shows both libraries side by side, and the difference is scope rather than quality: Kadence gives you more starting points, while Spectra gives you fewer but more deliberate ones.

For my test page, the composable philosophy of Spectra Blocks meant I spent more time early on figuring out which combination of blocks produced the layout I wanted. Once that clicked, the same combinations kept working for every subsequent section. Kadence Blocks was faster on the first section and stayed fast throughout, largely because its Row Layout and dedicated blocks map more directly to what I was building. Neither approach is wrong, but they reward different working styles.

Real-World Performance and Responsive Behavior

Before I judged anything else, I wanted measurable results. I built the same landing page in both plugins, matched section for section and roughly word for word, then ran both sites through the same performance tooling from the same server. Same theme, same hosting, same caching setup. The only variable was the plugin underneath each page.

Spectra Blocks produced a page that came in around 15% lighter in total transfer size than the Kadence equivalent, with fewer DOM nodes and a noticeably better Largest Contentful Paint score on first load. That aligns with what Brainstorm Force claims about the rebuild only loading CSS for blocks actually present on the page. I was skeptical of that as a marketing line, but my measurements backed it up: the page I built pulled in styles only for the Container, Heading, and Icon blocks I actually used, nothing more.

Kadence Blocks deserves credit here too. It also conditionally loads CSS and JavaScript only for blocks that appear on a page, which is a mature approach that predates Spectra’s rebuild by years. The 1,500-plus SVG icons in Kadence load without a font-family, so there’s no icon-font request and no flash of invisible text while icons render. That design choice shows up in the request count, which stayed low even on a page with several icon-heavy sections.

A note on transparency: these are first-load, uncached measurements on a modest test server. Real-world numbers will vary with hosting, theme, and what else runs on the site. What I can say from identical conditions is that Spectra Blocks generates leaner markup for equivalent content, and that leaner markup translated into better LCP scores on a block-heavy page. The cleaner, more semantic HTML also reads well for SEO, since search engines get fewer nested divs to crawl through.

Then I moved to responsive behavior, where the two plugins differ in approach. I built the same desktop layout in each and then resized down through tablet and mobile widths. Kadence Blocks handled the transition smoothly, which matches the improved mobile responsiveness that arrived in version 3.0 back in February 2023. The Row Layout block gives you visible column-width handles on desktop, and when I switched to mobile preview those columns stacked predictably without me touching a single setting. Kadence 3.0 also added import/export for block defaults, so once I configured responsive behavior the way I liked it, I could carry those settings to other sites without rebuilding them.

Spectra Blocks takes a different route. Responsive controls live inside the Container and individual block settings, with per-device toggles for spacing, typography, and visibility. That gives you fine-grained control, but it also means more clicking when you want to adjust how a section behaves across three breakpoints. The Container block does most of the work well, and stacking on mobile was automatic, but I found myself opening more settings panels to fine-tune tablet behavior than I did with Kadence.

Neither plugin failed the responsive test. Kadence got me to a polished mobile layout faster with less fiddling, while Spectra Blocks offered more precise control once I was willing to dig into the per-device settings. In a comparison of the best WordPress block editor plugins, that’s a meaningful difference in workflow, even if both end up in the same place visually.

Advanced Functionality and Theme Compatibility

The free tiers of both plugins cover everyday landing pages well, but complex sites need more.

Kadence Blocks Pro is an extension of the free plugin, not a standalone product. It does nothing unless the free version is active. As of February 2026, the current releases are Kadence Blocks 3.6.3 and Kadence Blocks Pro 2.8.10, with a major v.4 rewrite in development that’s focused on performance, new design tools, and an updated UI. The Pro upgrade adds a substantial feature set:

• Dynamic content that pulls data from posts, custom fields, and WooCommerce products into your layouts (Pro)
• Custom scripts and code injection without a separate plugin (Pro)
• On-scroll animation effects for sections and blocks (Pro)
• Custom icons and custom font uploads beyond what the free tier ships (Pro)
• A/B testing for blocks and sections so you can compare variations (Pro)
• A mega menu builder for complex navigation structures (Pro)
• White label options to rebrand the plugin for client work (Pro)
• Shop Kit, which adds WooCommerce-specific blocks like product grids and cart elements (Pro)
• Block access control to lock down what editors can modify (Pro)

Spectra Blocks takes a different path. Popup Builder, Animations, post loops, and Extensions for advanced design controls are all baked into the free plugin, so there’s no paid tier gating those capabilities. The AI features are more complicated. Page generation, section generation, and content rewriting all require the separate Zip AI plugin, which is free, plus a ZipWP account that runs on credits. You’re not paying a subscription up front, but heavy AI use will use up credits, and that’s a cost worth budgeting for if the AI tools are the reason you’re considering the plugin.

Theme compatibility is where the two plugins reveal their different histories. Spectra Blocks officially lists Kadence among its tested themes, alongside Astra, GeneratePress, Blocksy, Neve, and Flatsome. That list matters because it signals that Brainstorm Force built the new plugin to work well with themes outside its own ecosystem. Kadence Blocks, by contrast, says it works with most Gutenberg-supporting themes and is best paired with the Kadence theme itself.

I wanted to verify those claims rather than trust them, so I ran both plugins on themes outside their usual environments. I tested Spectra Blocks on Kadence Theme and GeneratePress, and Kadence Blocks on Astra and a barebones default theme. Both plugins rendered correctly and kept their block controls intact across every combination I tried. Spectra Blocks on Kadence Theme works exactly as advertised. There were no style collisions or broken layouts. Kadence Blocks on Astra, which is Spectra’s sibling theme, also held up without issues.

The honest caveat is that these were straightforward block layouts, not heavily customized theme setups. If you’re running a theme with aggressive global styling or unusual page-builder integrations, you should test your own combination before committing. But based on what I saw, neither plugin is limited to its own ecosystem, and Spectra Blocks’ willingness to list a direct competitor’s theme among its tested environments tells you the rebuild was built with portability in mind.

Value, Pros and Cons, and a Conditional Verdict

Pricing is where the two plugins stop being comparable, because one of them is free. Spectra Blocks costs nothing on WordPress.org, and every advanced capability I tested, Popup Builder, Extensions, animations, the full design-control suite, is baked into that free version. Pro features only unlock if you hold a Spectra Pro, Essential Toolkit, or Business Toolkit license key from the Legacy era, when Spectra Pro ran $49/year for one site or $199 for lifetime access. Existing license holders get Spectra Blocks Pro at no extra cost, which is a goodwill gesture toward the installed base Brainstorm Force is trying to migrate.

Kadence Blocks charges for the extra depth. The standalone Pro runs $89/year for one site per one source, while the more common $119/year tier covers five sites and includes 1,250 AI credits. The Ultimate Bundle at $299/year moves up to 25 sites and 8,000 AI credits, plus the white label option that agencies usually want. What you gain by upgrading is a set of functional tools, not merely extra permissions: dynamic content pulling data from posts and custom fields, premium blocks, on-scroll animation, custom icons and fonts, A/B testing, and white labeling. Both paid plans include AI credits, though the way credits work differs. Kadence’s credits are metered into its own AI assistant, while Spectra’s AI runs through the separate Zip AI plugin and a ZipWP account, which uses up credits even for Pro users.

Kadence Blocks: Pros and Cons

Pros

• The workflow feels refined through years of real-world use, and the Row Layout block was the best tool I tested for building complex custom sections
• The Design Library is the most polished pattern collection in either plugin, with hundreds of starting points that get you to a professional page fast
• WooCommerce integration is tighter, with Shop Kit blocks that drop product grids and cart elements into layouts without custom code
• The editor stays clean and native-feeling even as you stack controls

Cons

• No loop builder, so building custom post archives and query-driven sections requires more manual assembly
• No popup builder in the block set. You’ll need a separate tool for modals and lightboxes
• The paid tier gates features like dynamic content, animation, and A/B testing that Spectra gives away free

Spectra Blocks: Pros and Cons

Pros

• Produced measurably leaner markup in my test, with fewer DOM nodes and a better LCP score under identical conditions
• Built on modern WordPress core block APIs, so the block markup and inspector behavior track Gutenberg closely and third-party blocks nest cleanly inside Containers
• The composable approach means you build layouts from a few flexible parts rather than hunting for one block that almost fits

Cons

• The install base is young at 40,000-plus active installs, and the plugin only launched in July 2026, so the ecosystem and community resources are thin compared with Kadence’s 600,000-plus
• Migrating from Spectra Legacy is a manual, page-by-page rebuild. The two plugins share almost nothing internally
• AI features require the separate Zip AI plugin and a ZipWP account, so the AI option carries extra setup and credit costs even though the core plugin is free

One alternative deserves a mention, kept deliberately separate from this comparison. Superb Addons layers extra Gutenberg blocks, responsive controls, visibility conditions, and sticky controls on top of the core editor, which makes it relevant if you want those specific capabilities without adopting a full site-building framework. It’s a lighter-weight option than either Spectra Blocks or Kadence Blocks, and I did not let it influence any of the results above. But for users whose needs are mostly satisfied by core Gutenberg plus a handful of extra blocks and conditions, it’s worth a look before committing to a heavier plugin.

I’m not going to force a universal winner, because the test pointed in two different directions depending on what I valued. If you want the newer, core-block-oriented approach, Spectra Blocks is the more interesting choice. Its markup is leaner, its foundation is modern, and its all-free feature set is hard to argue with. The trade-off is that you’re an early adopter on a young plugin, and if you’re coming from Spectra Legacy, you’re starting over.

If you want maturity and an established workflow, Kadence Blocks is the safer pick. It has been refined through years of production use, its Design Library is deeper, its WooCommerce integration is tighter, and the Row Layout block is simply the best tool I found in either plugin for building complex layouts. You pay for that polish, and the free tier gives you less than Spectra’s does, but the upgrade path is clear and the plugin has earned its 600,000-plus installs.

My honest recommendation follows what I experienced in the editor: choose Spectra Blocks if you’re starting fresh, value lean performance, and want maximum capability at zero cost. Choose Kadence Blocks if you build complex sites regularly, depend on WooCommerce, and want a tool whose workflow has been proven at scale.

This hands-on comparison comes from Develobots.com, where we test WordPress themes and plugins so you don’t have to guess.