codehs.com website review

About 2.6 MB of JavaScript is downloaded but never used on this page. Google estimates it would make the page about 14.4 s faster on a phone.

10 files block the first paint until they finish downloading. Deferring or inlining them could save about 10.7 s.

15 files are served with short cache lifetimes, so returning visitors download them again (1.6 MB).

About 867 KiB of CSS is downloaded but never applied on this page. Google estimates it would make the page about 5.0 s faster on a phone.

1 image could be 687 KiB smaller with modern formats (WebP or AVIF) and sizes that fit a phone screen. Google estimates it would make the page about 3.4 s faster on a phone.

The page has 3,281 HTML elements. Above 1,500, rendering and every interaction get slower on phones.

Your mobile performance score is 53 (desktop: 55). Pages that score under 90 lose visitors before the first paint.

97 KiB could be saved by minifying JavaScript.

A phone's processor spends 3.3 s on main-thread work while loading, 844 ms of it running JavaScript. Above 2 s, taps and scrolls feel sluggish.

10 long tasks block the main thread while loading, the longest for 311 ms. During a long task the page ignores taps.

Google Tag Manager costs a phone 265 ms of main-thread work and 321 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.

8 third-party services load with your homepage (Google Tag Manager, Intercom and Other Google APIs/SDKs and others), adding 868 KiB and 491 ms of main-thread time.

Web fonts hide text while they load. Setting font-display: swap shows text immediately (about 50 ms).

Polyfills for old browsers add 18 KiB JavaScript that modern phones do not need.

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 first text or image appears after 25.7 s on a phone. Good is under 1.8 s.

Your largest element takes 42.8 s to render on a phone. Google's threshold for “good” is 2.5 s. The largest element is the text “The Top Coding and Computer Science Platform for K-12 Schoo…”.

Visually, the page fills in at 25.7 s (Speed Index). Good is under 3.4 s.

The page becomes fully interactive after 42.9 s. Good is under 3.8 s.

Real visitors wait 3.9 s for the largest content to appear (75th percentile). Good is under 2.5 s.

Real visitors see the first content after 2.5 s (75th percentile). Good is under 1.8 s.

14 images have no width and height attributes, so the layout jumps as each one loads.

Over the last 25 four-week periods to 2026-10-03, real Chrome visitors' tap response (inp) went from 243 ms to 254 ms at the 75th percentile (Chrome UX Report (opens in a new tab) history).

Over the last 25 four-week periods to 2026-10-03, real Chrome visitors' largest content (lcp) went from 3.0 s to 3.1 s at the 75th percentile (Chrome UX Report (opens in a new tab) history).

Your homepage downloads 7.3 MB in 81 requests on a phone: scripts 3.7 MB (36), images 1.5 MB (12) and fonts 1.0 MB (11). Under 2 MB keeps phones on slow connections fast.

5 images (717 KiB) are JPEG, PNG or GIF. The same pictures as WebP or AVIF are usually much smaller at the same quality, and every current browser shows them.

5 images further down the page (717 KiB) download before anyone scrolls to them. Adding loading="lazy" lets the first screen load first.

5 images are downloaded at several times the size a phone draws them, for example 2eccbd6d9f058784e4da62c3df543895 at 1,000 px wide, shown at 270 px. Resized copies would save about 247 KiB.

By the Sustainable Web Design model, a visit to your homepage emits about 2.07 g of CO₂e: 248.2 kg a year at 10,000 visits a month. It scales with page weight, so every byte cut lowers it.

Certain ARIA roles must be contained by particular parents: 4 elements on the page fail this check, rated critical by axe-core.

Certain ARIA roles must contain particular children: 1 element on the page fails this check, rated critical by axe-core.

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

Some list items are not inside a list.

Elements must only use permitted ARIA attributes: 1 element on the page fails this check, rated serious by axe-core.

Some lists contain elements other than list items, which screen readers announce wrongly.

1 tap target is too small or too close together to hit reliably with a finger.

All page content should be contained by landmarks: 1 element on the page fails this check, rated moderate by axe-core.

Elements with visible text labels do not have matching accessible names. (4 elements).

Your title is 70 characters, so Google will cut it off around 60: “The Top Coding and Computer Science Platform for K-12 Schools | CodeHS”.

Your meta description is 194 characters; Google truncates after about 160, so the end of your pitch is cut.

The homepage links to 385 pages on codehs.com and 55 external pages.

Your robots.txt lets ChatGPT search (OAI-SearchBot), ChatGPT (ChatGPT-User), Claude search (Claude-SearchBot), Claude (Claude-User), Perplexity (PerplexityBot) and Perplexity (Perplexity-User) read the homepage but closes other sections to them, so answers about those pages can't cite you.

Your homepage links to 4 pages by a URL that isn't their canonical one, for example /keyboarding, whose canonical is /typing. Linking straight to the canonical URL saves crawlers a detour and keeps ranking signals on one address.

We fetched 15 pages linked from your homepage (of 139 found) and read each the way a search engine does.

Large scripts ship without source maps.

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.

2 links go through two or more redirects, for example https://codehs.com/practice.

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.

codehs.com 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.

codehs.com's DNS answers are not signed. DNSSEC stops attackers forging them to send visitors or email elsewhere; most registrars switch it on in a click, though most sites still run without it.

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

There is no form on the homepage, so every lead has to click through to another page first.

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 1,696 words of visible text.

DMARC is set to p=none, so mail pretending to be codehs.com is still delivered. Reports are on, so moving to quarantine is the next step.

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 and Google Tag Manager (measured from a US location before any click). No consent tool was detected. Visitors from the EU, UK and several US states must be asked first.

Opening the homepage sets 12 cookies (measured from a US location before any click).

No known cookie consent tool loads with the page. Some sites build their own banner, and some only show one to visitors from the EU.

Loading the homepage contacts 20 hosts run by other companies (fonts, scripts, analytics, ads), each of which sees the visitor's IP address.