TanStack Start and Lovable: what changes?

TanStack Start is a full-stack React framework: it combines the visible website with routing, data loading and functions that run on the server. Lovable has used it by default for new projects since 13 May 2026. The main difference from the older React + Vite foundation is that a page can arrive as readable HTML before the browser executes the JavaScript.

That is a useful improvement for public websites. But SSR does not automatically make a site faster, safer or easier to find. Content, configuration and implementation still matter. This page explains what changes and what you still need to check.

What is Server-Side Rendering (SSR)?

Server-Side Rendering means the server builds the initial view of a page and sends it to the browser as HTML. Visitors do not need to run the app's JavaScript first to see the server-rendered text.

In a classic React app using Client-Side Rendering (CSR), the initial HTML usually contains a basic document and a place where React builds the page. The browser downloads JavaScript, executes it and fetches data if necessary. The content then appears.

With SSR, some of that work happens before the HTML reaches the browser. For example, the browser can already receive an article's heading, explanation and navigation. Stylesheets and images are still needed for the complete design. Some content may also load later.

An important distinction: React and Vite are not synonymous with CSR. React can render on the server, and Vite is a development and build tool. The difference is how the app is configured, not a limitation of React itself.

What happens after the initial view?

After the HTML arrives, React takes over the existing page and makes it interactive. This is called hydration: buttons, forms and other elements gain their behaviour.

SSR does not remove JavaScript. A visitor may be able to read the text while an interactive calculator is not ready yet. On subsequent navigation, TanStack Router can update pages in the browser without a full reload.

A hydration mismatch occurs when the first browser render differs from the server's HTML. A locally stored preference that immediately changes the text is one example. Stable initial values and reading browser information only after hydration help prevent this.

What is TanStack Start?

TanStack Start is a React framework for both browser and server work. It builds on TanStack Router and uses Vite. Routing, the initial page render, data loading and server functions therefore fit within the same application.

TanStack Start is not a CMS or an AI model. Lovable is the platform you use to describe and build your app; TanStack Start is part of the technical foundation of the resulting app.

What changed at Lovable?

Lovable announced the move to TanStack Start on 1 June 2026. According to that announcement, new projects from 13 May 2026 use TanStack Start and SSR by default. This did not automatically convert older projects to the same framework.

The older foundation used React + Vite, with page rendering mainly in the browser. Lovable also describes pre-rendering for existing projects: generating HTML in advance so visitors or crawlers do not depend solely on browser JavaScript. Pre-rendering and a full upgrade to TanStack Start are different things.

An upgrade feature is now available for older projects. Eligibility depends on the project. Check the official upgrade guide and the available project actions before planning a move.

You do not have to change how you build or manage every technical detail yourself. You can keep describing what you want in Lovable. Behind the scenes, however, the way pages are delivered and server work is organised changes.

Why can SSR help with SEO and AI visibility?

SSR can provide public text and structure directly in the HTML. This makes a page less dependent on whether a search engine or AI crawler can and will execute JavaScript.

Google can render JavaScript, but that adds a processing step. Other crawlers do not always execute the same scripts. When your explanation is in the initial HTML, it is easier to retrieve directly.

That does not mean every crawler sees the entire page. Text that appears only after a click or a browser request may still be absent. Content behind a login should not be publicly available.

Discoverability still requires:

• A unique title and description for each page.
• A correct canonical: the preferred address of that page.
• Reciprocal language links if you offer Dutch and English.
• Logical headings, descriptive links and useful, verifiable content.
• A sitemap and correct status codes, including a real 404 for unknown addresses.
• Structured data that matches what is visible on the page.

A framework alone does not earn a higher Google ranking or a mention in an AI answer. Read about SEO advice to understand which checks matter alongside the technology.

Are link previews on WhatsApp and LinkedIn more reliable?

SSR helps because the title, description and Open Graph tags can already be in the HTML when a service fetches the link. Many services that generate link previews do not execute a complete React app.

A good preview still depends on correct configuration. Each shareable page needs its own tags. An image must be available at a reachable, absolute HTTPS address. The service must be allowed to fetch the page.

WhatsApp, LinkedIn and Slack may cache old previews. An updated title or image therefore does not always appear immediately. A private page may not get a public preview either. “Always correct immediately” is not a promise SSR can deliver.

Is a TanStack Start site faster?

SSR can show the initial content sooner because the browser does not need to execute all the app code first. On the other hand, the server needs time to build the page and potentially retrieve data.

A slow data source can delay the first response. Large images, heavy scripts and lots of JavaScript remain problems with SSR. Streaming, which sends parts of the page progressively, and caching can help, but need appropriate configuration.

Measure several things: server response time, when the main content becomes visible, how quickly the page responds and whether elements shift. Core Web Vitals summarise some of these aspects. Compare the same page before and after a change under similar conditions.

What changes for security?

Server functions provide a clear place for sensitive operations and secret API keys. These can stay on the server rather than in the JavaScript files downloaded by your visitors.

That benefit only applies with correct implementation. Not every function or route loader runs exclusively on the server. In TanStack Start, sensitive code still needs an explicit server boundary. A browser-facing setting such as a VITE_ variable is not a safe place for a secret.

A server function can also be called by a requester. For each sensitive operation, check who is making the request, what data they may read or change, and whether the input is valid. Abuse prevention and cost monitoring matter for public functions. SSR does not replace access control or secure database rules.

Do not cache a personalised page as if it were public. A shared cache containing the previous visitor's data can leak information, even when the page loads quickly.

What does this mean for external hosting?

An app that renders pages on the server for each request needs a suitable server environment. Putting only the browser files in a static hosting bucket is not enough.

With a classic CSR app, you could often place the built HTML, CSS and JavaScript files on static hosting. Separate backend services were still needed for features such as accounts or data storage.

With TanStack Start, external hosting depends on the deployment configuration. This could be a Node.js server or a supported edge environment, for example. Lovable manages its own publishing environment; this Brandable project runs there on Cloudflare Workers. That does not mean every TanStack Start project must use Cloudflare.

There is an exception: TanStack Start also supports pre-rendering, generating certain pages as HTML during the build, and an SPA mode. Static hosting may suit entirely static pages. But server functions, dynamic SSR and other server components still need a runtime. Your export is not automatically a folder that works on any host.

When moving, also check environment variables, redirects, accounts, the database, files, email and monitoring. Consult the official external hosting guide and our explanation of managed hosting.

Should you upgrade an older Lovable site?

Not just because a newer framework exists. An upgrade is most useful when it solves a specific problem or supports further development. An older site that works well does not automatically need rebuilding.

Before upgrading, record what works now: important pages, forms, accounts, metadata and performance. Test the same elements in the preview after upgrading. Check direct visits to a deeper URL too, not just navigation from the homepage.

According to Lovable, the existing published version stays active until you publish the upgrade. The upgrade can be reverted through version history. This makes testing possible, but does not replace checking data and external integrations.

A practical lesson from our own site: a Dutch and an English page can look correct while their language links point to the wrong addresses. SSR simply delivers those incorrect tags sooner. Check the HTML and functionality, not just the appearance.

Checklist for your TanStack Start site

A sound foundation is only useful when the important pages and actions work correctly. At a minimum, check:

• Is the main public text in the HTML without executing JavaScript?
• Does each page have its own metadata and a self-referencing canonical?
• Do Dutch and English versions correctly link to each other?
• Do shared links and their images work without signing in?
• Do secret keys stay out of browser files?
• Do server functions validate access and input?
• Is personal data kept out of shared caches?
• Do forms, accounts and direct page addresses work after upgrading?
• Has performance been measured rather than assumed?
• Does any external host support all the server features you use?

Frequently asked questions about TanStack Start and Lovable

Does Lovable use TanStack Start for every project?

According to Lovable, new projects use it by default from 13 May 2026. Older projects were not automatically converted. Check your project settings and the upgrade guide for your own project.

Does TanStack Start replace React or Vite?

No. TanStack Start uses React and Vite, adding features including SSR, routing integration and server functions. It is a framework around that foundation, not a replacement for React.

What is the difference between SSR and pre-rendering?

Dynamic SSR builds HTML during a request. Pre-rendering generates HTML in advance, for example during the build. Both can deliver readable HTML without executing browser JavaScript first.

Does SSR automatically improve my site's visibility?

No. SSR makes public content easier to retrieve directly, but useful text, correct metadata, internal links and crawler access still matter. A better ranking is not guaranteed.

Do you still need JavaScript with SSR?

Usually, for interactive elements. The server can deliver the initial HTML; React then uses JavaScript to make the page interactive. This process is called hydration.

Are API keys automatically safe in TanStack Start?

No. Secret keys must be used inside server-only code and must not appear in browser files or public settings. Server functions also need access control and input validation.

Can I host TanStack Start outside Lovable?

Yes, with an appropriate deployment configuration. Dynamic SSR and server functions require a supported runtime. Only pre-generated static pages can run on static hosting without those server features.

Does an upgrade take time and credits?

The Lovable upgrade uses credits and requires checking the result. The work involved depends on your project and integrations. Check the current upgrade information before starting.

Sources and further reading

The platform information was checked on 30 October 2026. Features and upgrade conditions may change.

• Lovable: Building apps using TanStack Start, announcement dated 1 June 2026.
• Lovable: upgrading to TanStack Start.
• TanStack Start: SEO and rendering.
• TanStack Start: server functions.
• TanStack Start: execution model.
• TanStack Start: SPA mode.
• Lovable: external deployment and hosting.

Want to understand the wider possibilities? Explore our Lovable guide and Lovable for businesses. Want to know what this technology means for your website? Ask us your question.

Links to lovable.dev contain our partner code. We are a Lovable partner; that relationship does not change the limitations and considerations described here.