AI App Builder Embedding (2026): Can the App You Built Live Inside Someone Else's Site?

Quick answer (October 2026). Five of the eight AI app builders we track document a way to put what you built inside somebody else's page, and they are not five versions of the same feature. Base44 mints a one-time sign-in token so the frame opens already signed in as the person looking at it. Softr hands you a snippet for a whole page or for a single block. Lovable and v0 both embed a preview, and both say so plainly: Lovable's embed URL "does not grant access to the editor or the published app". Webflow does not use a frame at all, it exports your components as React source into your codebase. Bubble, Replit and Bolt.new document nothing. The question that separates them is not whether an iframe works. It is what the frame gets handed along with the pixels, and who is allowed to open one.

Embedding looks like a layout feature and behaves like an access-control feature

Put "can I embed it" in a comparison grid and you get eight ticks or eight crosses, because every one of these builders publishes to a URL and any URL can be dropped in an iframe. That grid is worthless.

The useful version of the question has three parts, and the vendors answer them in structurally different places:

1. What are you embedding? The published app, or a build preview that is not the published app.
2. Does the frame know who is looking? An embedded app with a login is a sign-in page inside a box unless somebody passes identity across the boundary.
3. Who is allowed to embed you? This is a security setting, it has a default, and on most of these platforms nobody tells you what the default is.

Only one builder answers all three. Two answer the first two and deliberately refuse the third. One answers none of them and substitutes a completely different mechanism.

What each builder actually documents

Every row is sourced to the vendor's own documentation, read on 1 October 2026, with the URLs in the Sources block. We have no embedding product to sell and no vendor reviewed this before publication.

Finding one: exactly one builder hands the frame an identity

Base44 is the only one of the eight that treats embedding as a signed-in experience rather than a display trick. Its page is titled "Embed the app" and its own summary line is the whole thesis.

Base44, verbatim: "Show an app inside your platform, already signed in as the person looking at it."

The mechanism is a three-step server-side flow. You provision the end user against the app with their email and a role. You then mint a sign-in token for that same email, choosing which build the frame should show. The response carries an embed_url with the token already attached, and an expiry that Base44 documents as sixty seconds. You set the iframe source to that URL once, because, in the vendor's words, "a token works only once, so mint a new one each time you load the frame".

Two details here are worth more than the headline. The first is that visibility decides whether you need a token at all: an app set to public without login can simply be loaded at its address, while both of the login-requiring states need one per end user. Base44 states the consequence of skipping it rather than leaving you to discover it, noting that without sign-in "the app can't tell who's looking at it, so anything that belongs to one person, such as their own saved data, doesn't work".

The second is a guard rail that will catch anyone testing with their own account. Minting a token for an app owner, an editor, or the service account your integration authenticates as returns a 403 with the error code privileged_user, because, as the documentation puts it, "sign-in tokens are for end users only". The first thing most people try is the first thing that is blocked.

Finding two: two builders embed a preview, and both say so

This is the distinction that makes a feature grid actively misleading, because "embed" appears in Lovable's and v0's documentation and neither is talking about your live app.

Lovable's embed URL endpoint is gated to Business or higher and its own description draws the line in one sentence.

Lovable, verbatim: "Creates a preview URL valid for one hour that can be loaded in an iframe on one exact HTTPS origin. Visitors do not need a Lovable login. It shows the project's built preview; it does not grant access to the editor or the published app."

The request takes a parent_origin and the response returns embed_url plus expires_at. So the access control is per call rather than per account: one token, one origin, one hour. That is a tighter default than anything else here, and it is also a feature aimed at people building a product on top of Lovable rather than at somebody who wants their finished app on a client's marketing site.

v0 goes further in the same direction and turns the boundary into architecture. Preview access is designed to run through your own backend, because a browser cannot attach the short-lived preview token as a header when loading a frame, so you point the frame at a proxy you control instead. That proxy has to run somewhere specific, and v0 is unusually blunt about where.

v0, verbatim: "Deploy the catch-all route, loading route, and proxy.ts on a preview-only origin whose registrable domain is different from your host application's registrable domain."

Different domain, not merely a different subdomain, and v0 spells out why: two hosts on the same site can still share cookies scoped to the parent domain. The frame sandbox must carry both allow-scripts and allow-same-origin, and v0 pre-empts the obvious misreading of the second one by noting there is no cross-origin sandbox token and that keeping the proxy origin is not the same as becoming same-origin with the parent page.

Then the sentence that makes v0 the exact inverse of Base44. The proxy "does not forward incoming Cookie, Authorization, or proxy authentication headers and removes upstream Set-Cookie headers", with the consequence stated outright: "preview applications that rely on server-side cookies will need an alternative authentication flow". Base44 engineers identity passthrough in. v0 engineers it out, on purpose, as a security boundary, because what it is framing is generated code it does not trust.

Finding three: only one builder embeds something smaller than a page

Softr is the only one of the eight with a documented unit below the page.

Softr, verbatim: "Softr allows you to embed any block or page on third-party site."

Block embed lives at the bottom of the Features tab in block settings and produces a snippet you paste wherever you need it. Page embed is a frame pointed at your Softr subdomain or custom domain plus a page path, paired with an iframe-resizer script so the frame grows with its contents. Both are gated to the Basic plan and above.

That granularity is a real differentiator and it comes with a real omission: nothing on the page addresses identity. If the Softr page you embed sits behind a login, the person looking at it is looking at a login form in a box on your site, and Softr documents no equivalent of Base44's token or Lovable's parent_origin. For an open directory or a public listing block this is the simplest option on the list. For anything user-specific it is the one that leaves the hardest problem to you.

Finding four: Webflow answers the question with source code

Webflow has no embed-your-site story in its developer documentation, and that is not an oversight, because it solves the same problem at compile time instead.

Webflow, verbatim: "DevLink is the interface between external codebases and Webflow."

DevLink runs in both directions. You can import your React components into Webflow, and you can export Webflow components as React code into your own project. The second direction is the one that answers this article's question: rather than framing a Webflow page inside your application, you take the markup and styles out as components and compile them in. Access control becomes irrelevant because nothing is being loaded across an origin boundary at runtime, and the whole class of cookie, storage and sandbox problems that occupies most of v0's guide simply does not arise.

The trade is equally clear. An exported component is a snapshot, so the Webflow route gives you the tightest integration and the weakest live link. Whether that is an advantage depends entirely on how often the embedded thing is supposed to change, which is the same question as which build your users are actually running.

Finding five: the default is "anyone", and only one vendor tells you

Base44 is the only builder in this comparison that documents a workspace-level policy for who may frame your apps, with three settings and an explicit starting position.

Base44, verbatim: "Your workspace starts at Anyone, which leaves each app to decide for itself. Nothing is restricted until you choose a policy."

Sites are added with a scheme, a leading wildcard covers subdomains, the list holds up to fifty entries, and permission is granted per website rather than per page. Base44 also warns that tightening the policy takes effect immediately and breaks any site already framing your apps, which is the kind of operational detail that normally only appears in a support ticket.

The sharpest part is elsewhere in Base44's own documentation. Its security scanner checks for a missing X-Frame-Options header and describes the risk in plain terms, noting that the header "stops your app from being displayed inside an iframe on another site" and that this "protects against clickjacking attacks". Clicking Fix sets the app's embedding to No one. So the vendor with the most developed embedding product also ships a scanner that flags the default state of that product as something to go and change. Both statements are correct and they are aimed at different readers, but seeing them side by side is the clearest argument on this page that embedding is a security setting wearing a layout feature's clothes.

For the other seven builders this question has no documented answer at all, which does not mean the apps are unframeable. It means the posture is whatever the platform's default headers happen to be, and you will find out by testing rather than by reading.

The three with nothing written down

Bubble's published documentation index runs to 596 entries and the string "embed" appears in none of them. We fetched the two pages most likely to carry it anyway, the shared element properties reference and the app deployment guide, and both contain zero occurrences.

Replit's index is likewise silent, and its publishing guide produces a tempting false positive: the page contains four matches for "embed" and "iframe" and every one of them belongs to the documentation site's own YouTube player component rather than to anything about your app.

Bolt.new documents hosting, publishing to a bolt.host address, sharing a project and inviting collaborators, and nothing about displaying the result inside another site.

State the limit honestly: six of these eight vendors publish an index of page titles and descriptions rather than full page content, so an index miss is weaker evidence than a page miss. That is why we fetched underlying pages for all three absences instead of stopping at the index. v0's index carries full content, which is the only reason its coverage can be characterised confidently in either direction.

The verdict, October 2026

If the app has a login and must appear inside a product you also control, Base44 is the only builder here with a documented answer, and the token flow is the reason. If you are building a platform where other people's generated apps are previewed inside yours, v0's guide is the most complete security model published by anyone in this group, and Lovable's per-call origin binding is the simplest version of the same idea. If you want a public page or a single block on a marketing site with no login involved, Softr's block embed is the least work by a wide margin. If the embedded thing is design rather than application, Webflow's export is a better fit than any frame.

And if you are on Bubble, Replit or Bolt.new, the honest position is that you are testing an undocumented behaviour. The app will very likely load in a frame. Whether it keeps working when the platform tightens its headers, and whether anyone can tell you in advance, is a different question, and it belongs next to the one about whether your own measurement survives the boundary at all, because browser storage inside a third-party frame is exactly where analytics quietly stops matching reality.

One durability note. Plan gating moves faster than mechanisms do, so the gates quoted here, Business or higher on Lovable and Basic and above on Softr, are the most perishable facts on this page. The shapes behind them, a token versus an origin binding versus a code export, are the parts worth choosing on.