builder.io website review

Your mobile performance score is 61 (desktop: 84). Pages that score under 90 lose visitors before the first paint.

8 third-party services load with your homepage (Google Tag Manager, Facebook and reddit and others), adding 1.1 MB and 809 ms of main-thread time.

About 481 KiB of JavaScript is downloaded but never used on this page. Google estimates it would make the page about 300 ms faster on a phone.

2 files block the first paint until they finish downloading. Deferring or inlining them could save about 750 ms.

Google Tag Manager costs a phone 430 ms of main-thread work and 537 KiB of downloads while your page loads. Loading it after the page is usable, or only on the pages that need it, takes that off the critical path.

17 files are served with short cache lifetimes, so returning visitors download them again (416 KiB).

A phone's processor spends 2.3 s on main-thread work while loading, 1.4 s of it running JavaScript. Above 2 s, taps and scrolls feel sluggish.

The page has 1,546 HTML elements. Above 1,500, rendering and every interaction get slower on phones.

About 35 KiB of CSS is downloaded but never applied on this page. Google estimates it would make the page about 150 ms faster on a phone.

10 long tasks block the main thread while loading, the longest for 170 ms. During a long task the page ignores taps.

3 images could be 64 KiB smaller with modern formats (WebP or AVIF) and sizes that fit a phone screen.

Polyfills for old browsers add 49 KiB JavaScript that modern phones do not need.

8 KiB could be saved by minifying JavaScript.

Critical files load one after another instead of in parallel (3 chains). Preconnecting to key origins and preloading the hero image shortens the chain.

Scripts make the browser recalculate the layout repeatedly while the page loads, which wastes processor time on phones.

Real Chrome users on phones do not pass Google's Core Web Vitals on this page (28-day field data from the Chrome UX Report (opens in a new tab)). Google uses this in ranking.

The page becomes fully interactive after 17.8 s. Good is under 3.8 s.

The first text or image appears after 4.5 s on a phone. Good is under 1.8 s.

Your largest element takes 4.7 s to render on a phone. Google's threshold for “good” is 2.5 s. The largest element is the text “Build software with your team and agents Maya • Designer De…”.

Real visitors see the first content after 2.0 s (75th percentile). Good is under 1.8 s.

Real visitors wait 987 ms for your server to start answering (75th percentile). Good is under 800 ms.

Scripts block taps and scrolling for 445 ms in total while the page loads. Good is under 200 ms.

Visually, the page fills in at 4.5 s (Speed Index). Good is under 3.4 s.

Over the last 25 four-week periods to 2026-10-17, real Chrome visitors' largest content (lcp) went from 1.9 s to 1.8 s at the 75th percentile (Chrome UX Report (opens in a new tab) history).

Your homepage downloads 2.3 MB in 212 requests on a phone: scripts 1.8 MB (135), images 223 KiB (19) and other files 76 KiB (52). Under 2 MB keeps phones on slow connections fast.

1 image further down the page (35 KiB) download before anyone scrolls to it. Adding loading="lazy" lets the first screen load first.

By the Sustainable Web Design model, a visit to your homepage emits about 0.64 g of CO₂e: 77.0 kg a year at 10,000 visits a month. It scales with page weight, so every byte cut lowers it.

Elements must only use permitted ARIA attributes: 23 elements on the page fail this check, rated serious by axe-core.

14 text elements don't have enough contrast against the background to read easily, especially outdoors on a phone.

The skip-link target should exist and be focusable: 1 element on the page fails this check, rated moderate by axe-core.

1 form field has no label, so screen readers announce an empty box and autofill guesses.

Elements with visible text labels do not have matching accessible names. (6 elements).

No structured data (JSON-LD), so Google can't show rich results such as your logo, ratings or FAQs.

The homepage links to 65 pages on builder.io and 7 external pages.

There is no Organization (or LocalBusiness) JSON-LD, so search engines and AI assistants have no machine-readable facts about who runs the site: its name, logo, profiles and contact details.

Your homepage links to 3 pages by a URL that isn't their canonical one, for example /prototypes, whose canonical is /use-cases/prototypes. Linking straight to the canonical URL saves crawlers a detour and keeps ranking signals on one address.

/demo has no <h1> headline, so visitors and search engines get no clear main topic.

We fetched 15 pages linked from your homepage (of 53 found) and read each the way a search engine does.

1 image failed to load on a phone, for example https://bat.bing.com/action/0?ti=343262080&tm=gtm002&Ver=2&mid=77dc0fdc-6c3d-4296-a80e-94def825f212&bo=1&sid=5c7a6e10cd8211f1a392274d8f86d180&vid=5c7a9270cd8211f1be55f3b409b9e631&vids=1&msclkid=N&pi=9.

2 errors were logged to the browser console while the page loaded, for example “Failed to load resource: net::ERR_CERT_VERIFIER_CHANGED”.

No Strict-Transport-Security header, so browsers may still try plain http first on a return visit.

No Content-Security-Policy header, the main browser-side defence against injected scripts.

X-Content-Type-Options: nosniff is missing, so browsers may guess file types.

No Referrer-Policy header, so full URLs can leak to the sites you link to.

No Permissions-Policy header to switch off camera, microphone and location for embedded content.

There is no /.well-known/security.txt telling researchers how to report a security problem to you.

builder.io has no CAA record, so any certificate authority may issue a certificate for it. A CAA record naming your provider (for example letsencrypt.org) closes that door.

Social proof on the homepage: 1 trust badge. Pairing it with named testimonials or customer logos makes it far more convincing.

No phone number or email link on the homepage, so ready-to-buy visitors have one fewer way to reach you.

No guarantee or risk reducer (money-back, free trial, no credit card) is mentioned, which is often what tips a hesitant visitor.

The homepage carries about 948 words of visible text.

Email authentication: SPF record 25 points, plus 15 when it ends in -all (10 for ~all); DMARC record 25, plus 25 for a reject policy (15 for quarantine); a DKIM key on a common selector 10.

Before a visitor clicks anything, the page loads Google Ads, Google Analytics, Google Tag Manager, LinkedIn Insight and Meta Pixel and 3 mores (measured from a US location before any click). A consent tool (OneTrust) is installed; check it blocks these until visitors agree where the law requires it.

Opening the homepage sets 28 cookies (measured from a US location before any click).

Loading the homepage contacts 36 hosts run by other companies (fonts, scripts, analytics, ads), each of which sees the visitor's IP address.