How to add X-Frame-Options on Lovable / static hosting

Last updated November 11, 2026 · Reviewed by a CISSP-certified security practitioner

To add X-Frame-Options on Lovable / static hosting, set the header in src/server.ts (TanStack Start) or your edge proxy with the value DENY. Prevents your site being embedded in iframes (clickjacking). Publish, then curl -I your live domain. Then confirm it with curl -I or a free FixSecurityHeaders scan.

What does X-Frame-Options do?

X-Frame-Options (or the modern CSP frame-ancestors) tells browsers whether other sites may put your pages inside an iframe.

Risk if missing: Attackers can overlay your page invisibly and trick users into clicking buttons (clickjacking) — e.g. changing settings or confirming payments.

What is the Lovable / static hosting configuration?

Add this to src/server.ts (TanStack Start) or your edge proxy:

src/server.ts (TanStack Start) or your edge proxy

// src/server.ts — wrap the response before returning it
function withSecurityHeaders(res: Response): Response {
  const out = new Response(res.body, res);
  const h = out.headers;
  h.set("X-Frame-Options", "DENY");
  return out;
}

How do I add it step by step?

Open src/server.ts (TanStack Start) or your edge proxy.
Paste the X-Frame-Options configuration shown below.
Publish, then curl -I your live domain.
Run curl -I https://yourdomain.com and look for the x-frame-options line.
Scan your site on FixSecurityHeaders to confirm the grade improved.

How do I verify it worked?

terminal

curl -sI https://yourdomain.com | grep -i "x-frame-options"
# expected:
# x-frame-options: DENY

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What are the common mistakes?

Use SAMEORIGIN if your own site frames its pages.
ALLOW-FROM is obsolete; use CSP frame-ancestors for allow-lists.
If CSP frame-ancestors is present, modern browsers ignore X-Frame-Options.
Pure static hosts that don't allow custom headers can be fronted by Cloudflare to add them.
Skip frame-blocking headers on preview URLs that are shown inside editors.

Quick reference

Header	`X-Frame-Options`
Recommended value	`DENY`
Stack	Lovable / static hosting
Where	src/server.ts (TanStack Start) or your edge proxy
Compliance	OWASP ASVS V14.4.7, NIST 800-171 3.13.1, CMMC SC.L2-3.13.1

FAQ

What value should I use for X-Frame-Options?

A safe default is DENY. Use SAMEORIGIN if your own site frames its pages.

Why isn't X-Frame-Options showing up on Lovable / static hosting?

Pure static hosts that don't allow custom headers can be fronted by Cloudflare to add them. Also clear any CDN or page cache, and check you edited the config that actually serves your domain.

Does X-Frame-Options affect SEO or performance?

No measurable performance cost — it's a few bytes per response. It doesn't affect rankings directly, but a misconfigured policy can break page resources, so test before enforcing.

Which compliance frameworks reference X-Frame-Options?

OWASP ASVS V14.4.7, NIST 800-171 3.13.1, CMMC SC.L2-3.13.1.