Is Htmx 4.0 Worth Using? Performance, Benchmarks & What Changed

Few front-end libraries have generated as much debate as htmx. Rather than moving more logic into the browser, it pushes most of the work back to the server and uses HTML fragments instead of JSON wherever possible. That philosophy hasn’t changed in version 4.0. What has changed is the underlying networking layer, making this one of the most significant technical updates the project has received.

Is htmx faster than react?

In many cases, yes—but the answer depends on the application.

One of htmx’s biggest advantages is its small footprint. The core library is around 14–16KB compressed, compared to roughly 42–47KB for React and react-dom before any application code is added. That smaller bundle reduces the amount of JavaScript browsers need to download and execute, giving htmx an edge in first-load performance, particularly on slower networks.

Benchmarks reflect that advantage, although they shouldn’t be treated as universal. In one comparison, an htmx dashboard loaded in 412 milliseconds versus 2,847 milliseconds for an equivalent React application, with Lighthouse scores of 94 and 34 respectively under throttled 3G conditions. The results come from a single project and naturally favor htmx’s server-rendered approach, so they shouldn’t be interpreted as proof that every htmx application will outperform React.

Adoption tells a different story. Despite its smaller bundle, htmx sees far fewer npm downloads than Alpine.js or React. Many production projects also pair htmx with a lightweight library such as Alpine.js to handle client-side state, reducing some of its size advantage while still remaining lighter than a typical React stack.

Overall, htmx’s smaller payload consistently benefits server-rendered applications and bandwidth-constrained environments. For highly interactive applications with significant client-side state, React’s larger ecosystem and tooling often outweigh the performance gains of a smaller bundle.

What’s new in htmx 4.0?

The biggest change isn’t something users will immediately notice in the interface. Htmx 4.0 replaces XMLHttpRequest with the modern Fetch API, bringing native streaming support, a redesigned extension system, and cleaner integration with modern browser features. Although most developers won’t notice the transport layer directly, it lays the groundwork for capabilities that were difficult or impossible to implement with the older API.

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The migration is intentionally gradual. Beta releases have been available throughout 2026, while htmx 2.0 continues to receive long-term support. That gives existing projects plenty of time to evaluate the new release before making the switch, rather than forcing an immediate upgrade.

What are the downsides of htmx?

The biggest complaint about htmx isn’t performance rather it’s debugging. When something goes wrong, the failure is often silent. A button may stop responding without producing an obvious error, leaving developers to inspect requests, targets, and returned HTML fragments before identifying the problem. While htmx provides debugging helpers such as htmx.logAll(), the experience still isn’t as polished as the developer tooling available in React.

SEO is another area that requires extra planning. Since htmx loads parts of a page dynamically, search engines may not always see content delivered after the initial request. Projects that depend heavily on organic search need to ensure important content is present in the initial HTML or rendered server-side.

Finally, htmx’s minimalism has a cost: it deliberately does not manage client-side state, so projects with meaningful client-only interactivity often end up reaching for an additional library or framework anyway, and the surrounding tooling ecosystem is less mature than what’s built up around larger frameworks like React.

Pros

• Free and permissively licensed under 0BSD / BSD Zero Clause, with no cost to adopt
• A core library around 14-16 kilobytes compressed, far lighter than React’s 42-47KB baseline
• Modernized transport via fetch() replacing XMLHttpRequest, plus native streaming and a redesigned extension system
• Long-term support commitment: htmx 2.0 continues indefinitely alongside 4.0’s rollout, reducing forced-upgrade pressure
• Strong measured performance in at least one case study, with Lighthouse scores of 94 versus 34 against React under throttled conditions

Cons

• Debugging silent failures is a recurring pain point, with the click-and-nothing-happens problem being the most common complaint
• Declarative event handling is harder to trace than standard imperative JavaScript without extra tooling
• SEO requires deliberate mitigation since dynamically loaded content may not be indexed
• Smaller ecosystem and less mature tooling than React’s surrounding infrastructure
• Far smaller adoption base: about 718,000 monthly npm downloads versus Next.js’s roughly 39.6 million weekly downloads, which matters for hiring and community support

Who should use htmx?

Best for:

• Server-rendered applications and content sites where minimal JavaScript and fast first loads matter
• Solo developers and small teams who want to avoid a JavaScript build pipeline and npm dependency sprawl
• Internal tools and admin panels where SEO is irrelevant and client-state complexity is low
• Teams comfortable pairing htmx with a client-side helper like Alpine.js for the interactivity htmx doesn’t cover

Not ideal for:

• Teams building complex, state-heavy single-page applications with deep client-side interactivity
• Public-facing, SEO-critical sites without the resources to add server-side rendering safeguards
• Organizations that need to hire quickly from a large existing talent pool, given React’s dominance in the Stack Overflow Developer Survey 2024 and Next.js’s much larger following in GitHub stars (139,600 vs. 47,740)
• Projects that depend on a mature plugin/tooling ecosystem out of the box

Is htmx 4.0 worth it?

Htmx 4.0 doesn’t try to compete with React or Next.js on ecosystem size, third-party tooling, or client-side capabilities. Instead, it focuses on delivering fast, server-driven interfaces with as little JavaScript as possible. That approach won’t suit every project, but for content-heavy websites, internal tools, and server-rendered applications, it remains one of the most compelling lightweight alternatives available. Teams that need rich client-side state management or a larger hiring pool will still be better served by React-based frameworks.

Specs and benchmark summary

Metric	Htmx	React	Next.js	Alpine.js
License/cost	Free, 0BSD	Free	Free	Free
Bundle size (gzipped)	~14-16KB	~42-47KB	N/A (framework)	~7.1KB
Weekly npm downloads (approx.)	~158,000	94K-96M range	~39.6M	~498,000
GitHub stars	~47,740	N/A	~139,600	N/A
Case-study Lighthouse score (3G)	94	34	N/A	N/A
4.0 release status	Beta5, June 2026	N/A	N/A	N/A

Overall, htmx 4.0 is an incremental but meaningful engineering update to a library that already had a clear niche. It doesn’t compete with React and Next.js on ecosystem size or client-side capability, and it isn’t trying to. For the specific job of building fast, server-driven web interfaces without a JavaScript toolchain, the data supports it as a credible, low-cost option — provided the debugging and SEO trade-offs are accounted for up front.

Frequently asked questions

What is the biggest change in htmx 4.0? The biggest change is the switch from XMLHttpRequest to the fetch() API as htmx’s default transport, described in the project’s own essay as “the fetch()ening.” This also brings a redesigned extension system, an explicit attribute-inheritance modifier (:inherited), and native streaming support for progressively rendering server responses.

Is htmx 4.0 faster than React? In one case study, an htmx dashboard loaded in 412 milliseconds versus 2,847 milliseconds for an equivalent React single-page app, with Lighthouse scores of 94 versus 34 under throttled 3G conditions. That gap is case-specific and favors htmx’s server-rendered model on slow connections; htmx’s smaller bundle size (~14-16KB versus React’s ~42-47KB) reliably helps first-load performance, but it does not guarantee the same margin on every project or connection type.

Is htmx 2.0 still supported after 4.0 releases? Yes. The htmx team has committed to supporting htmx 2.0 indefinitely, so existing projects are not forced onto the 4.0 timeline. This gives teams a long runway to evaluate the beta before adopting it in production.

What are the main downsides of using htmx? The most cited issues are silent debugging failures (a click producing no visible error or response), the need for extra work to make dynamically loaded content SEO-friendly, and a smaller, less mature tooling ecosystem compared to React. Htmx also doesn’t manage client-side state, so many projects pair it with a library like Alpine.js.

Who should avoid htmx? Teams building complex, state-heavy single-page applications, public SEO-critical sites without resources for server-side rendering safeguards, and organizations that need to hire quickly from a large talent pool are generally better served by React or Next.js, given htmx’s smaller adoption base and ecosystem.