United Stated · New York Completed: Apr 16, 2026 17:49 UTCMobile 375 × 812
Desktop 1440 × 900
Score: 71 / 100
Based on 8 categories, 0 sections
Room to improve — your 47.9s load time is above Google's 2.5s 'Good' threshold.
Several missing protections leave your users and data exposed.
Several issues make your site difficult for assistive technology users.
Well-optimized for search — your content is discoverable.
Solid infrastructure — fast server responses across the board.
Mostly compliant — a few items need attention.
Missing metadata means poor previews on social media and search.
Heavier than average — reducing page weight saves energy and bandwidth.
The overall score is a weighted average of individual category scores. Categories with more impact on user experience and security carry more weight.
Weights reflect general web best practices. Individual needs may differ.
'unsafe-eval' found in script source
Security gaps expose your site and users to attacks, eroding trust.
'unsafe-inline' found in script source
Security gaps expose your site and users to attacks, eroding trust.
Page weighs 10.5 MB (10.2 MB transferred)
Performance issues directly impact user engagement and conversion rates.
10 image-only link(s) without alt text
Accessibility issues exclude users with disabilities — up to 15% of your potential audience.
31 link(s) with no accessible text
Accessibility issues exclude users with disabilities — up to 15% of your potential audience.
High impact, low effort — start here.
High impact, requires investment.
Small gains, minimal effort.
Nothing in this quadrant — good news.
Low impact, high effort — do last.
Nothing in this quadrant — good news.
[](https://beavercheck.com/results/e88a8389-e9d7-47b7-9acd-7ef73bf2ff10)<a href="https://beavercheck.com/results/e88a8389-e9d7-47b7-9acd-7ef73bf2ff10"><img src="https://beavercheck.com/badge?url=https%3A%2F%2Floc.gov" alt="BeaverCheck Score"></a>https://beavercheck.com/badge?url=https%3A%2F%2Floc.govThis badge auto-updates with your latest scan result.
Your site performs reasonably well, but a few targeted fixes could meaningfully improve results. Your LCP of 47.9s exceeds Google's 2.5s 'Good' threshold and the 1 performance issue below directly contributes to it. Accessibility issues exclude users who rely on assistive technology — an estimated 15% of your potential audience. Addressing the critical issues below would have the most immediate impact on your user trust.
8 barrier(s) likely increasing bounce by ~33%.
Page takes 47.9s to load
+12% bounceUsers abandon at ~3s — you're 45.4s over the 2.5s threshold
Fix: Optimize render-blocking resources, preload the hero image, and compress images
High main-thread blocking time
+2% bouncePage is non-interactive for 300ms after first paint
Fix: Defer third-party scripts and split large bundles
Mixed content on HTTPS page
+8% bounceBrowsers block insecure subresources — broken images, missing scripts, warning badge
Fix: Change http:// URLs inside the page to https:// (or protocol-relative)
No HSTS header
+1% bounceReturning visitors are briefly exposed to downgrade attacks on first request
Fix: Set Strict-Transport-Security: max-age=31536000; includeSubDomains
No Content-Security-Policy header
+1% bounceHigher XSS blast radius — one compromised script can exfiltrate the checkout form
Fix: Ship a reporting-only CSP first, then enforce once violations are clean
No structured data
+2% bounceNo rich-result eligibility in Google — lower SERP CTR vs competitors with stars and prices
Fix: Add JSON-LD for your page type (Product, Article, FAQPage, LocalBusiness, …)
31 link(s) with generic text ("click here", "read more")
+1% bounceScreen-reader users navigating by link list see no context — and search engines can't infer relevance
Fix: Rewrite with descriptive phrases that identify the destination
45 broken link(s) on the page
+5% bounceClicks land on 404s — trust drops and the session often ends
Fix: Fix or remove the broken destinations surfaced on the Content tab
Preliminary CRO audit — each barrier links to the tab with detailed analysis.
$600 investment → $2.56/month returns + USD 157,500 risk avoided
$600
6h · 5 findings
$2.56 /mo
~$31 / year
USD 157,500
if kept compliant
$100 — in quick wins — start here for the fastest payback
Figures combine localized regulatory fine ceilings, search/conversion value priced against local CPC, and bandwidth waste estimates. Results depend on implementation quality and audience composition. Not legal or financial advice.
6.0 developer hours at $100/hr
Based on United States rates ($100/hr)
Start here for the best return on investment
$13,128 / month at risk
~$157,531 / year if left unfixed
$157,500
+3 more
$2.56 /mo
32040.9 MB/mo × 0.080 USD/GB
Compliance figures represent the statutory maximum fine for the most severe triggered category, capped per regulation — not the sum of per-finding penalties. Based on published regulatory fine ranges. This is not legal advice.
Unique monthly visitors from your analytics
Purchases, signups, or key actions
Optional — for revenue estimation
more engaged visitors from reduced bounce
Fix 5 critical issues to capture this value
Based on Google/Deloitte research ("Milliseconds Make Millions") showing a ~7% bounce rate increase per additional second of LCP above the 2.5s "Good" threshold.
Your site's LCP: → estimated after fixes.
These are estimates based on industry research — actual results vary
Your data stays in your browser — nothing is sent to our servers
Thanks for your feedback!
We'll use a cached audit if available, or offer to scan.
Industry-standard audits powered by Google Lighthouse.
Key metrics that affect user experience.
First Contentful Paint First Contentful Paint — how long until the browser renders the first piece of content. Under 1.8s is good.
6.84 s
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
47.89 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
300 ms
Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.
0.000
Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.
9.65 s
Time to Interactive Time to Interactive — how long until the page is fully interactive and responds to user input. Under 3.8s is good.
48.11 s
Audit breakdown by category with detailed findings.
Remove large, duplicate JavaScript modules from bundles to reduce unnecessary bytes consumed by network activity.
Performance issues directly impact user engagement and conversion rates.
Polyfills and transforms enable older browsers to use new JavaScript features. However, many aren't necessary for modern browsers. Consider modifying your JavaScript build process to not transpile Baseline features, unless you know you must support older browsers. Learn why most sites can deploy ES6+ code without transpiling
Shipping ES5 transpiled code to modern browsers wastes bytes — every user with an evergreen browser pays for compatibility you don't need.
Most users today run browsers that natively support ES6+, async/await, optional chaining, and the rest of modern JavaScript. Transpiling to ES5 'just in case' adds 20-40% to your bundle for no benefit. Configure your build to target a modern browserslist, or ship a differential bundle pair (modern + legacy) with the module/nomodule pattern.
Source: Google web.dev / Lighthouse
3rd party code can significantly impact load performance. Reduce and defer loading of 3rd party code to prioritize your page's content.
Performance issues directly impact user engagement and conversion rates.
A long cache lifetime can speed up repeat visits to your page. Learn more about caching.
Performance issues directly impact user engagement and conversion rates.
Your first network request is the most important. Reduce its latency by avoiding redirects, ensuring a fast server response, and enabling text compression.
Performance issues directly impact user engagement and conversion rates.
A forced reflow occurs when JavaScript queries geometric properties (such as offsetWidth) after styles have been invalidated by a change to the DOM state. This can result in poor performance. Learn more about forced reflows and possible mitigations.
Performance issues directly impact user engagement and conversion rates.
Reducing the download time of images can improve the perceived load time of the page and LCP. Learn more about optimizing image size
Performance issues directly impact user engagement and conversion rates.
| URL | Resource Size | Est Savings | |
|---|---|---|---|
Archive technician Courtney Holschuh examines a strip of the long-lost film “Gu… div.slick-list > div.slick-track > div.featured-slider-slide > img | www.loc.gov/static/home/images/featured/collections/Gugusse1200x560.png | 1.5 MiB | 1.5 MiB |
A crowd of people move through the lobby during the 2024 Library of Congress Na… div.slick-list > div.slick-track > div.featured-slider-slide > img | www.loc.gov/static/home/images/featured/nbf/NBF20261200x560.jpeg | 1.5 MiB | 1.5 MiB |
A view of the Great Hall of the Thomas Jefferson Building of the Library of Con… div.slick-list > div.slick-track > div.featured-slider-slide > img | www.loc.gov/static/home/images/featured/programs/live24-1200x560.jpg | 768.7 KiB | 729.2 KiB |
li.trending-item > a#trending_content_1 > span.trending-item-image > img li.trending-item > a#trending_content_1 > span.trending-item-image > img | www.loc.gov/static/home/images/trending/blogs/PaulRevere480x320.jpeg | 337.9 KiB | 325.8 KiB |
Exterior view of the U.S. Capitol with blue sky and green lawn div.slick-list > div.slick-track > div.featured-slider-slide > img | www.loc.gov/static/home/images/featured/evergreen/congress_A-L.jpg | 259.7 KiB | 220.2 KiB |
li.trending-item > a#trending_content_3 > span.trending-item-image > img li.trending-item > a#trending_content_3 > span.trending-item-image > img | www.loc.gov/static/home/images/trending/evergreen/news2022_480x320.jpg | 194.9 KiB | 182.8 KiB |
li.trending-item > a#trending_content_2 > span.trending-item-image > img li.trending-item > a#trending_content_2 > span.trending-item-image > img | www.loc.gov/static/home/images/trending/lcm/2026_LCM_0304_thumbnail.jpg | 192.6 KiB | 180.5 KiB |
li.trending-item > a#trending_content_4 > span.trending-item-image > img li.trending-item > a#trending_content_4 > span.trending-item-image > img | www.loc.gov/static/home/images/trending/evergreen/events2022_480x320.jpg | 176.1 KiB | 163.9 KiB |
ul.your-library-links > li > a > img ul.your-library-links > li > a > img | www.loc.gov/static/home/images/your-library/02-ResearchCenter.jpg | 177.5 KiB | 160.0 KiB |
li.trending-item > a#trending_content_6 > span.trending-item-image > img li.trending-item > a#trending_content_6 > span.trending-item-image > img | www.loc.gov/static/home/images/trending/blogs/TelephoneCall480x320.jpeg | 154.9 KiB | 142.8 KiB |
A female singer stands in the foreground along with the text reading Library of… div.slick-list > div.slick-track > div.featured-slider-slide > img | www.loc.gov/static/home/images/featured/programs/2026SpringConcert_1200x560.jpg | 181.1 KiB | 141.7 KiB |
li.trending-item > a#trending_content_5 > span.trending-item-image > img li.trending-item > a#trending_content_5 > span.trending-item-image > img | /static/home/images/trending/exhibits/exhibitions-evergre... | 108.0 KiB | 95.5 KiB |
div.mejs__inner > div.mejs__mediaelement > mediaelementwrapper#mejs_5202820535671885 > video#mejs_5202820535671885_html5 div.mejs__inner > div.mejs__mediaelement > mediaelementwrapper#mejs_5202820535671885 > video#mejs_5202820535671885_html5 | /static/home/images/trending/video-screenshots/2025-staff... | 131.8 KiB | 94.3 KiB |
ul.your-library-links > li > a > img ul.your-library-links > li > a > img | www.loc.gov/static/home/images/your-library/03-AskLibrarian.jpg | 29.1 KiB | 11.6 KiB |
li#featured_public_domain_3 > figure > a > img li#featured_public_domain_3 > figure > a > img | www.loc.gov/static/portals/free-to-use/public-domain/baseball-cards/3_1407bv.jpg | 28.5 KiB | 7.8 KiB |
ul.your-library-links > li > a > img ul.your-library-links > li > a > img | www.loc.gov/static/home/images/your-library/01-PlanYourVisit.jpg | 22.3 KiB | 4.8 KiB |
Optimize LCP by making the LCP image discoverable from the HTML immediately, and avoiding lazy-loading
Performance issues directly impact user engagement and conversion rates.
Avoid chaining critical requests by reducing the length of chains, reducing the download size of resources, or deferring the download of unnecessary resources to improve page load.
Performance issues directly impact user engagement and conversion rates.
Requests are blocking the page's initial render, which may delay LCP. Deferring or inlining can move these network requests out of the critical path.
Performance issues directly impact user engagement and conversion rates.
| URL | Transfer Size | Duration |
|---|---|---|
| www.loc.gov/static/js/lib/jquery-1.8.2.js | 261.1 KiB | 1.2 s |
| www.loc.gov/static/stylesheets/base.css | 386.3 KiB | 2.9 s |
| /dac62e20b491e735c6b56e64c39134d8ee93f9cf/satelliteLib-6b... | 80.3 KiB | 1.5 s |
These insights are also available in the Chrome DevTools Performance Panel - record a trace to view more detailed information.
Time to Interactive is the amount of time it takes for the page to become fully interactive. Learn more about the Time to Interactive metric.
Performance issues directly impact user engagement and conversion rates.
Redirects introduce additional delays before the page can be loaded. Learn how to avoid page redirects.
Performance issues directly impact user engagement and conversion rates.
| URL | Time Spent |
|---|---|
| loc.gov/ | 799 ms |
| www.loc.gov/ | 0.0 ms |
The maximum potential First Input Delay that your users could experience is the duration of the longest task. Learn more about the Maximum Potential First Input Delay metric.
Performance issues directly impact user engagement and conversion rates.
Minifying CSS files can reduce network payload sizes. Learn how to minify CSS.
Performance issues directly impact user engagement and conversion rates.
| URL | Transfer Size | Est Savings |
|---|---|---|
| www.loc.gov/static/stylesheets/base.css | 386.3 KiB | 86.0 KiB |
| .your-library { max-width: 85.71428571rem; width: 100%; margin: 0 auto; padding: 0 2rem; … } … | 12.8 KiB | 2.6 KiB |
| .public-domain { max-width: 85.71428571rem; width: 100%; margin: 0 auto; padding: 0 2rem; … } … | 6.8 KiB | 2.1 KiB |
Minifying JavaScript files can reduce payload sizes and script parse time. Learn how to minify JavaScript.
Performance issues directly impact user engagement and conversion rates.
| URL | Transfer Size | Est Savings |
|---|---|---|
| www.loc.gov/static/javascript/base.js | 3.0 MiB | 1.2 MiB |
| www.loc.gov/static/js/lib/jquery-1.8.2.js | 260.6 KiB | 119.6 KiB |
| inline: jQuery(function($) { /* G… | 13.2 KiB | 6.9 KiB |
| inline: // Stub window.loc_ux_tracking so we d… | 7.8 KiB | 4.6 KiB |
| inline: jQuery(function($){ // This is a cr… | 5.3 KiB | 3.6 KiB |
| inline: /** * Timing.js 1.0.4 * Copyright 20… | 5.1 KiB | 3.2 KiB |
| inline: /* ben frain https://benfrain.com/a-ho… | 6.9 KiB | 2.4 KiB |
Reduce unused rules from stylesheets and defer CSS not used for above-the-fold content to decrease bytes consumed by network activity. Learn how to reduce unused CSS.
Performance issues directly impact user engagement and conversion rates.
| URL | Transfer Size | Est Savings |
|---|---|---|
| www.loc.gov/static/stylesheets/base.css | 385.6 KiB | 363.6 KiB |
Reduce unused JavaScript and defer loading scripts until they are required to decrease bytes consumed by network activity. Learn how to reduce unused JavaScript.
Multi-megabyte JavaScript bundles delay every interactive feature on the page.
This is the Lighthouse audit fired when too much JS is shipped relative to what executes. The fix isn't a config flag — it requires bundle analysis (webpack-bundle-analyzer, rollup-plugin-visualizer), splitting routes into chunks, lazy-loading off-screen components, and removing unused dependencies. Fundamentally different from minification: minifying reduces byte count, this reduces what's downloaded at all.
Source: Google web.dev / Lighthouse
| URL | Transfer Size | Est Savings |
|---|---|---|
| www.loc.gov/static/javascript/base.js | 3.0 MiB | 2.1 MiB |
| www.loc.gov/static/js/lib/jquery-1.8.2.js | 260.6 KiB | 102.4 KiB |
| /dac62e20b491e735c6b56e64c39134d8ee93f9cf/satelliteLib-6b... | 80.0 KiB | 29.8 KiB |
Consider reducing the time spent parsing, compiling, and executing JS. You may find delivering smaller JS payloads helps with this. Learn how to reduce Javascript execution time.
Performance issues directly impact user engagement and conversion rates.
| URL | Total CPU Time | Script Evaluation | Script Parse |
|---|---|---|---|
| www.loc.gov/static/javascript/base.js | 817 ms | 309 ms | 405 ms |
| www.loc.gov/static/js/lib/jquery-1.8.2.js | 631 ms | 468 ms | 38 ms |
| Unattributable | 559 ms | 19 ms | 0.0 ms |
| www.loc.gov/ | 406 ms | 40 ms | 28 ms |
| /dac62e20b491e735c6b56e64c39134d8ee93f9cf/satelliteLib-6b... | 299 ms | 243 ms | 42 ms |
Consider reducing the time spent parsing, compiling and executing JS. You may find delivering smaller JS payloads helps with this. Learn how to minimize main-thread work
Performance issues directly impact user engagement and conversion rates.
| Category | Time Spent |
|---|---|
| Script Evaluation | 1.1 s |
| Other | 615 ms |
| Script Parsing & Compilation | 518 ms |
| Style & Layout | 396 ms |
| Parse HTML & CSS | 105 ms |
| Rendering | 45 ms |
Large network payloads cost users real money and are highly correlated with long load times. Learn how to reduce payload sizes.
Performance issues directly impact user engagement and conversion rates.
Set an explicit width and height on image elements to reduce layout shifts and improve CLS. Learn how to set image dimensions
Performance issues directly impact user engagement and conversion rates.
| URL | |
|---|---|
Exterior view of the U.S. Capitol with blue sky and green lawn div.slick-list > div.slick-track > div.featured-slider-slide > img | www.loc.gov/static/home/images/featured/evergreen/congress_A-L.jpg |
A crowd of people move through the lobby during the 2024 Library of Congress Na… div.slick-list > div.slick-track > div.featured-slider-slide > img | www.loc.gov/static/home/images/featured/nbf/NBF20261200x560.jpeg |
Archive technician Courtney Holschuh examines a strip of the long-lost film “Gu… div.slick-list > div.slick-track > div.featured-slider-slide > img | www.loc.gov/static/home/images/featured/collections/Gugusse1200x560.png |
A female singer stands in the foreground along with the text reading Library of… div.slick-list > div.slick-track > div.featured-slider-slide > img | www.loc.gov/static/home/images/featured/programs/2026SpringConcert_1200x560.jpg |
A view of the Great Hall of the Thomas Jefferson Building of the Library of Con… div.slick-list > div.slick-track > div.featured-slider-slide > img | www.loc.gov/static/home/images/featured/programs/live24-1200x560.jpg |
Exterior view of the U.S. Capitol with blue sky and green lawn div.slick-list > div.slick-track > div.featured-slider-slide > img | www.loc.gov/static/home/images/featured/evergreen/congress_A-L.jpg |
A crowd of people move through the lobby during the 2024 Library of Congress Na… div.slick-list > div.slick-track > div.featured-slider-slide > img | www.loc.gov/static/home/images/featured/nbf/NBF20261200x560.jpeg |
Archive technician Courtney Holschuh examines a strip of the long-lost film “Gu… div.slick-list > div.slick-track > div.featured-slider-slide > img | www.loc.gov/static/home/images/featured/collections/Gugusse1200x560.png |
A female singer stands in the foreground along with the text reading Library of… div.slick-list > div.slick-track > div.featured-slider-slide > img | www.loc.gov/static/home/images/featured/programs/2026SpringConcert_1200x560.jpg |
A view of the Great Hall of the Thomas Jefferson Building of the Library of Con… div.slick-list > div.slick-track > div.featured-slider-slide > img | www.loc.gov/static/home/images/featured/programs/live24-1200x560.jpg |
Exterior view of the U.S. Capitol with blue sky and green lawn div.slick-list > div.slick-track > div.featured-slider-slide > img | www.loc.gov/static/home/images/featured/evergreen/congress_A-L.jpg |
li#featured_public_domain_6 > figure > a > img li#featured_public_domain_6 > figure > a > img | www.loc.gov/static/portals/free-to-use/public-domain/baseball-cards/6_1558fv.jpg |
li#featured_public_domain_1 > figure > a > img li#featured_public_domain_1 > figure > a > img | www.loc.gov/static/portals/free-to-use/public-domain/baseball-cards/1_0006fv.jpg |
li#featured_public_domain_10 > figure > a > img li#featured_public_domain_10 > figure > a > img | /static/portals/free-to-use/public-domain/baseball-cards/... |
li#featured_public_domain_9 > figure > a > img li#featured_public_domain_9 > figure > a > img | www.loc.gov/static/portals/free-to-use/public-domain/baseball-cards/9_0188fv.jpg |
li#featured_public_domain_3 > figure > a > img li#featured_public_domain_3 > figure > a > img | www.loc.gov/static/portals/free-to-use/public-domain/baseball-cards/3_1407bv.jpg |
li#featured_public_domain_2 > figure > a > img li#featured_public_domain_2 > figure > a > img | www.loc.gov/static/portals/free-to-use/public-domain/baseball-cards/2_1407fv.jpg |
li#featured_public_domain_12 > figure > a > img li#featured_public_domain_12 > figure > a > img | /static/portals/free-to-use/public-domain/baseball-cards/... |
li#featured_public_domain_5 > figure > a > img li#featured_public_domain_5 > figure > a > img | www.loc.gov/static/portals/free-to-use/public-domain/baseball-cards/5_0068fv.jpg |
li#featured_public_domain_7 > figure > a > img li#featured_public_domain_7 > figure > a > img | www.loc.gov/static/portals/free-to-use/public-domain/baseball-cards/7_0015fv.jpg |
li#featured_public_domain_8 > figure > a > img li#featured_public_domain_8 > figure > a > img | www.loc.gov/static/portals/free-to-use/public-domain/baseball-cards/8_0072fv.jpg |
ul.your-library-links > li > a > img ul.your-library-links > li > a > img | www.loc.gov/static/home/images/your-library/01-PlanYourVisit.jpg |
ul.your-library-links > li > a > img ul.your-library-links > li > a > img | www.loc.gov/static/home/images/your-library/02-ResearchCenter.jpg |
ul.your-library-links > li > a > img ul.your-library-links > li > a > img | www.loc.gov/static/home/images/your-library/03-AskLibrarian.jpg |
li#featured_public_domain_11 > figure > a > img li#featured_public_domain_11 > figure > a > img | /static/portals/free-to-use/public-domain/baseball-cards/... |
li#featured_public_domain_4 > figure > a > img li#featured_public_domain_4 > figure > a > img | www.loc.gov/static/portals/free-to-use/public-domain/baseball-cards/4_1993fv.jpg |
More information about the performance of your application. These numbers don't directly affect the Performance score.
These checks highlight opportunities to improve the accessibility of your web app. Automatic detection can only detect a subset of issues and does not guarantee the accessibility of your web app, so manual testing is also encouraged.
Assistive technologies, like screen readers, can't interpret ARIA attributes with invalid values. Learn more about valid values for ARIA attributes.
Performance issues directly impact user engagement and conversion rates.
| Failing Elements |
|---|
Time Slider div.mejs__inner > div.mejs__controls > div.mejs__time-rail > span.mejs__time-total |
Focusable descendents within an `[aria-hidden="true"]` element prevent those interactive elements from being available to users of assistive technologies like screen readers. Learn how `aria-hidden` affects focusable elements.
Performance issues directly impact user engagement and conversion rates.
| Failing Elements |
|---|
previous main.home-container > nav.horizontal-scrolling-navigation-wrapper > div#horizontalScrollingNavigation > button#horizontalScrollingNavigationAdvancerLeft |
next main.home-container > nav.horizontal-scrolling-navigation-wrapper > div#horizontalScrollingNavigation > button#horizontalScrollingNavigationAdvancerRight |
These are opportunities to improve the usage of ARIA in your application which may enhance the experience for users of assistive technology, like a screen reader.
Low-contrast text is difficult or impossible for many users to read. Learn how to provide sufficient color contrast.
Performance issues directly impact user engagement and conversion rates.
| Failing Elements |
|---|
Benjamin K. Edwards Collection main.home-container > section.public-domain > p > a |
These are opportunities to improve the legibility of your content.
Link text (and alternate text for images, when used as links) that is discernible, unique, and focusable improves the navigation experience for screen reader users. Learn how to make links accessible.
Performance issues directly impact user engagement and conversion rates.
| Failing Elements |
|---|
ul.search-results > li#featured_public_domain_1 > figure > a ul.search-results > li#featured_public_domain_1 > figure > a |
ul.search-results > li#featured_public_domain_2 > figure > a ul.search-results > li#featured_public_domain_2 > figure > a |
ul.search-results > li#featured_public_domain_3 > figure > a ul.search-results > li#featured_public_domain_3 > figure > a |
ul.search-results > li#featured_public_domain_4 > figure > a ul.search-results > li#featured_public_domain_4 > figure > a |
ul.search-results > li#featured_public_domain_5 > figure > a ul.search-results > li#featured_public_domain_5 > figure > a |
ul.search-results > li#featured_public_domain_6 > figure > a ul.search-results > li#featured_public_domain_6 > figure > a |
ul.search-results > li#featured_public_domain_7 > figure > a ul.search-results > li#featured_public_domain_7 > figure > a |
ul.search-results > li#featured_public_domain_8 > figure > a ul.search-results > li#featured_public_domain_8 > figure > a |
ul.search-results > li#featured_public_domain_9 > figure > a ul.search-results > li#featured_public_domain_9 > figure > a |
ul.search-results > li#featured_public_domain_10 > figure > a ul.search-results > li#featured_public_domain_10 > figure > a |
ul.search-results > li#featured_public_domain_11 > figure > a ul.search-results > li#featured_public_domain_11 > figure > a |
ul.search-results > li#featured_public_domain_12 > figure > a ul.search-results > li#featured_public_domain_12 > figure > a |
These are opportunities to improve the semantics of the controls in your application. This may enhance the experience for users of assistive technology, like a screen reader.
Touch targets with sufficient size and spacing help users who may have difficulty targeting small controls to activate the targets. Learn more about touch targets.
Performance issues directly impact user engagement and conversion rates.
| Failing Elements |
|---|
Previous main.home-container > section.featured > div#featured-slider > button.slick-prev |
Next main.home-container > section.featured > div#featured-slider > button.slick-next |
These items highlight common accessibility best practices.
Source maps translate minified code to the original source code. This helps developers debug in production. In addition, Lighthouse is able to provide further insights. Consider deploying source maps to take advantage of these benefits. Learn more about source maps.
Performance issues directly impact user engagement and conversion rates.
These checks ensure that your page is following basic search engine optimization advice. There are many additional factors Lighthouse does not score here that may affect your search ranking, including performance on Core Web Vitals. Learn more about Google Search Essentials.
Industry-standard audits powered by Google Lighthouse. — Desktop
Key metrics that affect user experience. — Desktop
First Contentful Paint First Contentful Paint — how long until the browser renders the first piece of content. Under 1.8s is good.
1.45 s
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
5.51 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
44 ms
Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.
0.000
Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.
2.08 s
Time to Interactive Time to Interactive — how long until the page is fully interactive and responds to user input. Under 3.8s is good.
7.32 s
Audit breakdown by category with detailed findings.
Remove large, duplicate JavaScript modules from bundles to reduce unnecessary bytes consumed by network activity.
Performance issues directly impact user engagement and conversion rates.
Polyfills and transforms enable older browsers to use new JavaScript features. However, many aren't necessary for modern browsers. Consider modifying your JavaScript build process to not transpile Baseline features, unless you know you must support older browsers. Learn why most sites can deploy ES6+ code without transpiling
Shipping ES5 transpiled code to modern browsers wastes bytes — every user with an evergreen browser pays for compatibility you don't need.
Most users today run browsers that natively support ES6+, async/await, optional chaining, and the rest of modern JavaScript. Transpiling to ES5 'just in case' adds 20-40% to your bundle for no benefit. Configure your build to target a modern browserslist, or ship a differential bundle pair (modern + legacy) with the module/nomodule pattern.
Source: Google web.dev / Lighthouse
3rd party code can significantly impact load performance. Reduce and defer loading of 3rd party code to prioritize your page's content.
Performance issues directly impact user engagement and conversion rates.
A long cache lifetime can speed up repeat visits to your page. Learn more about caching.
Performance issues directly impact user engagement and conversion rates.
Your first network request is the most important. Reduce its latency by avoiding redirects, ensuring a fast server response, and enabling text compression.
Performance issues directly impact user engagement and conversion rates.
A forced reflow occurs when JavaScript queries geometric properties (such as offsetWidth) after styles have been invalidated by a change to the DOM state. This can result in poor performance. Learn more about forced reflows and possible mitigations.
Performance issues directly impact user engagement and conversion rates.
Reducing the download time of images can improve the perceived load time of the page and LCP. Learn more about optimizing image size
Performance issues directly impact user engagement and conversion rates.
| URL | Resource Size | Est Savings | |
|---|---|---|---|
Archive technician Courtney Holschuh examines a strip of the long-lost film “Gu… div.slick-list > div.slick-track > div.featured-slider-slide > img | www.loc.gov/static/home/images/featured/collections/Gugusse1200x560.png | 1.5 MiB | 1.4 MiB |
A crowd of people move through the lobby during the 2024 Library of Congress Na… div.slick-list > div.slick-track > div.featured-slider-slide > img | www.loc.gov/static/home/images/featured/nbf/NBF20261200x560.jpeg | 1.5 MiB | 1.4 MiB |
A view of the Great Hall of the Thomas Jefferson Building of the Library of Con… div.slick-list > div.slick-track > div.featured-slider-slide > img | www.loc.gov/static/home/images/featured/programs/live24-1200x560.jpg | 768.7 KiB | 659.3 KiB |
li.trending-item > a#trending_content_1 > span.trending-item-image > img li.trending-item > a#trending_content_1 > span.trending-item-image > img | www.loc.gov/static/home/images/trending/blogs/PaulRevere480x320.jpeg | 337.9 KiB | 330.3 KiB |
li.trending-item > a#trending_content_3 > span.trending-item-image > img li.trending-item > a#trending_content_3 > span.trending-item-image > img | www.loc.gov/static/home/images/trending/evergreen/news2022_480x320.jpg | 194.9 KiB | 187.3 KiB |
li.trending-item > a#trending_content_2 > span.trending-item-image > img li.trending-item > a#trending_content_2 > span.trending-item-image > img | www.loc.gov/static/home/images/trending/lcm/2026_LCM_0304_thumbnail.jpg | 192.6 KiB | 185.0 KiB |
li.trending-item > a#trending_content_4 > span.trending-item-image > img li.trending-item > a#trending_content_4 > span.trending-item-image > img | www.loc.gov/static/home/images/trending/evergreen/events2022_480x320.jpg | 176.1 KiB | 168.4 KiB |
ul.your-library-links > li > a > img ul.your-library-links > li > a > img | www.loc.gov/static/home/images/your-library/02-ResearchCenter.jpg | 177.5 KiB | 165.2 KiB |
Exterior view of the U.S. Capitol with blue sky and green lawn div.slick-list > div.slick-track > div.featured-slider-slide > img | www.loc.gov/static/home/images/featured/evergreen/congress_A-L.jpg | 259.7 KiB | 150.3 KiB |
li.trending-item > a#trending_content_6 > span.trending-item-image > img li.trending-item > a#trending_content_6 > span.trending-item-image > img | www.loc.gov/static/home/images/trending/blogs/TelephoneCall480x320.jpeg | 154.9 KiB | 147.3 KiB |
li.trending-item > a#trending_content_5 > span.trending-item-image > img li.trending-item > a#trending_content_5 > span.trending-item-image > img | /static/home/images/trending/exhibits/exhibitions-evergre... | 108.0 KiB | 100.2 KiB |
div.mejs__inner > div.mejs__mediaelement > mediaelementwrapper#mejs_5789364727797353 > video#mejs_5789364727797353_html5 div.mejs__inner > div.mejs__mediaelement > mediaelementwrapper#mejs_5789364727797353 > video#mejs_5789364727797353_html5 | /static/home/images/trending/video-screenshots/2025-staff... | 131.8 KiB | 94.3 KiB |
A female singer stands in the foreground along with the text reading Library of… div.slick-list > div.slick-track > div.featured-slider-slide > img | www.loc.gov/static/home/images/featured/programs/2026SpringConcert_1200x560.jpg | 181.1 KiB | 71.8 KiB |
ul.your-library-links > li > a > img ul.your-library-links > li > a > img | www.loc.gov/static/home/images/your-library/03-AskLibrarian.jpg | 29.1 KiB | 16.7 KiB |
li#featured_public_domain_3 > figure > a > img li#featured_public_domain_3 > figure > a > img | www.loc.gov/static/portals/free-to-use/public-domain/baseball-cards/3_1407bv.jpg | 28.5 KiB | 11.2 KiB |
ul.your-library-links > li > a > img ul.your-library-links > li > a > img | www.loc.gov/static/home/images/your-library/01-PlanYourVisit.jpg | 22.3 KiB | 9.9 KiB |
li#featured_public_domain_6 > figure > a > img li#featured_public_domain_6 > figure > a > img | www.loc.gov/static/portals/free-to-use/public-domain/baseball-cards/6_1558fv.jpg | 29.6 KiB | 7.7 KiB |
Optimize LCP by making the LCP image discoverable from the HTML immediately, and avoiding lazy-loading
Performance issues directly impact user engagement and conversion rates.
Avoid chaining critical requests by reducing the length of chains, reducing the download size of resources, or deferring the download of unnecessary resources to improve page load.
Performance issues directly impact user engagement and conversion rates.
Requests are blocking the page's initial render, which may delay LCP. Deferring or inlining can move these network requests out of the critical path.
Performance issues directly impact user engagement and conversion rates.
| URL | Transfer Size | Duration |
|---|---|---|
| www.loc.gov/static/js/lib/jquery-1.8.2.js | 261.1 KiB | 240 ms |
| www.loc.gov/static/stylesheets/base.css | 386.2 KiB | 480 ms |
| /dac62e20b491e735c6b56e64c39134d8ee93f9cf/satelliteLib-6b... | 80.3 KiB | 329 ms |
These insights are also available in the Chrome DevTools Performance Panel - record a trace to view more detailed information.
Redirects introduce additional delays before the page can be loaded. Learn how to avoid page redirects.
Performance issues directly impact user engagement and conversion rates.
| URL | Time Spent |
|---|---|
| loc.gov/ | 250 ms |
| www.loc.gov/ | 0.0 ms |
Time to Interactive is the amount of time it takes for the page to become fully interactive. Learn more about the Time to Interactive metric.
Performance issues directly impact user engagement and conversion rates.
The maximum potential First Input Delay that your users could experience is the duration of the longest task. Learn more about the Maximum Potential First Input Delay metric.
Performance issues directly impact user engagement and conversion rates.
Minifying CSS files can reduce network payload sizes. Learn how to minify CSS.
Performance issues directly impact user engagement and conversion rates.
| URL | Transfer Size | Est Savings |
|---|---|---|
| www.loc.gov/static/stylesheets/base.css | 386.2 KiB | 86.0 KiB |
| .your-library { max-width: 85.71428571rem; width: 100%; margin: 0 auto; padding: 0 2rem; … } … | 12.8 KiB | 2.6 KiB |
| .public-domain { max-width: 85.71428571rem; width: 100%; margin: 0 auto; padding: 0 2rem; … } … | 6.8 KiB | 2.1 KiB |
Minifying JavaScript files can reduce payload sizes and script parse time. Learn how to minify JavaScript.
Performance issues directly impact user engagement and conversion rates.
| URL | Transfer Size | Est Savings |
|---|---|---|
| www.loc.gov/static/javascript/base.js | 3.0 MiB | 1.2 MiB |
| www.loc.gov/static/js/lib/jquery-1.8.2.js | 260.6 KiB | 119.6 KiB |
| inline: jQuery(function($) { /* G… | 13.2 KiB | 6.9 KiB |
| inline: // Stub window.loc_ux_tracking so we d… | 7.8 KiB | 4.6 KiB |
| inline: jQuery(function($){ // This is a cr… | 5.3 KiB | 3.6 KiB |
| inline: /** * Timing.js 1.0.4 * Copyright 20… | 5.1 KiB | 3.2 KiB |
| inline: /* ben frain https://benfrain.com/a-ho… | 6.9 KiB | 2.4 KiB |
Reduce unused rules from stylesheets and defer CSS not used for above-the-fold content to decrease bytes consumed by network activity. Learn how to reduce unused CSS.
Performance issues directly impact user engagement and conversion rates.
| URL | Transfer Size | Est Savings |
|---|---|---|
| www.loc.gov/static/stylesheets/base.css | 385.6 KiB | 364.2 KiB |
| .your-library { max-width: 85.71428571rem; width: 100%; margin: 0 auto; padding: 0 2rem; … } … | 12.6 KiB | 10.1 KiB |
Reduce unused JavaScript and defer loading scripts until they are required to decrease bytes consumed by network activity. Learn how to reduce unused JavaScript.
Multi-megabyte JavaScript bundles delay every interactive feature on the page.
This is the Lighthouse audit fired when too much JS is shipped relative to what executes. The fix isn't a config flag — it requires bundle analysis (webpack-bundle-analyzer, rollup-plugin-visualizer), splitting routes into chunks, lazy-loading off-screen components, and removing unused dependencies. Fundamentally different from minification: minifying reduces byte count, this reduces what's downloaded at all.
Source: Google web.dev / Lighthouse
| URL | Transfer Size | Est Savings |
|---|---|---|
| www.loc.gov/static/javascript/base.js | 3.0 MiB | 2.1 MiB |
| www.loc.gov/static/js/lib/jquery-1.8.2.js | 260.6 KiB | 102.6 KiB |
| /dac62e20b491e735c6b56e64c39134d8ee93f9cf/satelliteLib-6b... | 80.0 KiB | 29.8 KiB |
Large network payloads cost users real money and are highly correlated with long load times. Learn how to reduce payload sizes.
Performance issues directly impact user engagement and conversion rates.
Set an explicit width and height on image elements to reduce layout shifts and improve CLS. Learn how to set image dimensions
Performance issues directly impact user engagement and conversion rates.
| URL | |
|---|---|
Exterior view of the U.S. Capitol with blue sky and green lawn div.slick-list > div.slick-track > div.featured-slider-slide > img | www.loc.gov/static/home/images/featured/evergreen/congress_A-L.jpg |
A crowd of people move through the lobby during the 2024 Library of Congress Na… div.slick-list > div.slick-track > div.featured-slider-slide > img | www.loc.gov/static/home/images/featured/nbf/NBF20261200x560.jpeg |
Archive technician Courtney Holschuh examines a strip of the long-lost film “Gu… div.slick-list > div.slick-track > div.featured-slider-slide > img | www.loc.gov/static/home/images/featured/collections/Gugusse1200x560.png |
A female singer stands in the foreground along with the text reading Library of… div.slick-list > div.slick-track > div.featured-slider-slide > img | www.loc.gov/static/home/images/featured/programs/2026SpringConcert_1200x560.jpg |
A view of the Great Hall of the Thomas Jefferson Building of the Library of Con… div.slick-list > div.slick-track > div.featured-slider-slide > img | www.loc.gov/static/home/images/featured/programs/live24-1200x560.jpg |
Exterior view of the U.S. Capitol with blue sky and green lawn div.slick-list > div.slick-track > div.featured-slider-slide > img | www.loc.gov/static/home/images/featured/evergreen/congress_A-L.jpg |
A crowd of people move through the lobby during the 2024 Library of Congress Na… div.slick-list > div.slick-track > div.featured-slider-slide > img | www.loc.gov/static/home/images/featured/nbf/NBF20261200x560.jpeg |
Archive technician Courtney Holschuh examines a strip of the long-lost film “Gu… div.slick-list > div.slick-track > div.featured-slider-slide > img | www.loc.gov/static/home/images/featured/collections/Gugusse1200x560.png |
A female singer stands in the foreground along with the text reading Library of… div.slick-list > div.slick-track > div.featured-slider-slide > img | www.loc.gov/static/home/images/featured/programs/2026SpringConcert_1200x560.jpg |
A view of the Great Hall of the Thomas Jefferson Building of the Library of Con… div.slick-list > div.slick-track > div.featured-slider-slide > img | www.loc.gov/static/home/images/featured/programs/live24-1200x560.jpg |
Exterior view of the U.S. Capitol with blue sky and green lawn div.slick-list > div.slick-track > div.featured-slider-slide > img | www.loc.gov/static/home/images/featured/evergreen/congress_A-L.jpg |
li#featured_public_domain_6 > figure > a > img li#featured_public_domain_6 > figure > a > img | www.loc.gov/static/portals/free-to-use/public-domain/baseball-cards/6_1558fv.jpg |
li#featured_public_domain_1 > figure > a > img li#featured_public_domain_1 > figure > a > img | www.loc.gov/static/portals/free-to-use/public-domain/baseball-cards/1_0006fv.jpg |
li#featured_public_domain_10 > figure > a > img li#featured_public_domain_10 > figure > a > img | /static/portals/free-to-use/public-domain/baseball-cards/... |
li#featured_public_domain_9 > figure > a > img li#featured_public_domain_9 > figure > a > img | www.loc.gov/static/portals/free-to-use/public-domain/baseball-cards/9_0188fv.jpg |
li#featured_public_domain_3 > figure > a > img li#featured_public_domain_3 > figure > a > img | www.loc.gov/static/portals/free-to-use/public-domain/baseball-cards/3_1407bv.jpg |
li#featured_public_domain_2 > figure > a > img li#featured_public_domain_2 > figure > a > img | www.loc.gov/static/portals/free-to-use/public-domain/baseball-cards/2_1407fv.jpg |
li#featured_public_domain_12 > figure > a > img li#featured_public_domain_12 > figure > a > img | /static/portals/free-to-use/public-domain/baseball-cards/... |
li#featured_public_domain_5 > figure > a > img li#featured_public_domain_5 > figure > a > img | www.loc.gov/static/portals/free-to-use/public-domain/baseball-cards/5_0068fv.jpg |
li#featured_public_domain_7 > figure > a > img li#featured_public_domain_7 > figure > a > img | www.loc.gov/static/portals/free-to-use/public-domain/baseball-cards/7_0015fv.jpg |
li#featured_public_domain_8 > figure > a > img li#featured_public_domain_8 > figure > a > img | www.loc.gov/static/portals/free-to-use/public-domain/baseball-cards/8_0072fv.jpg |
ul.your-library-links > li > a > img ul.your-library-links > li > a > img | www.loc.gov/static/home/images/your-library/01-PlanYourVisit.jpg |
ul.your-library-links > li > a > img ul.your-library-links > li > a > img | www.loc.gov/static/home/images/your-library/02-ResearchCenter.jpg |
ul.your-library-links > li > a > img ul.your-library-links > li > a > img | www.loc.gov/static/home/images/your-library/03-AskLibrarian.jpg |
li#featured_public_domain_11 > figure > a > img li#featured_public_domain_11 > figure > a > img | /static/portals/free-to-use/public-domain/baseball-cards/... |
li#featured_public_domain_4 > figure > a > img li#featured_public_domain_4 > figure > a > img | www.loc.gov/static/portals/free-to-use/public-domain/baseball-cards/4_1993fv.jpg |
More information about the performance of your application. These numbers don't directly affect the Performance score.
These checks highlight opportunities to improve the accessibility of your web app. Automatic detection can only detect a subset of issues and does not guarantee the accessibility of your web app, so manual testing is also encouraged.
Assistive technologies, like screen readers, can't interpret ARIA attributes with invalid values. Learn more about valid values for ARIA attributes.
Performance issues directly impact user engagement and conversion rates.
| Failing Elements |
|---|
Time Slider div.mejs__inner > div.mejs__controls > div.mejs__time-rail > span.mejs__time-total |
These are opportunities to improve the usage of ARIA in your application which may enhance the experience for users of assistive technology, like a screen reader.
Low-contrast text is difficult or impossible for many users to read. Learn how to provide sufficient color contrast.
Performance issues directly impact user engagement and conversion rates.
| Failing Elements |
|---|
Benjamin K. Edwards Collection main.home-container > section.public-domain > p > a |
These are opportunities to improve the legibility of your content.
Link text (and alternate text for images, when used as links) that is discernible, unique, and focusable improves the navigation experience for screen reader users. Learn how to make links accessible.
Performance issues directly impact user engagement and conversion rates.
| Failing Elements |
|---|
ul.search-results > li#featured_public_domain_1 > figure > a ul.search-results > li#featured_public_domain_1 > figure > a |
ul.search-results > li#featured_public_domain_2 > figure > a ul.search-results > li#featured_public_domain_2 > figure > a |
ul.search-results > li#featured_public_domain_3 > figure > a ul.search-results > li#featured_public_domain_3 > figure > a |
ul.search-results > li#featured_public_domain_4 > figure > a ul.search-results > li#featured_public_domain_4 > figure > a |
ul.search-results > li#featured_public_domain_5 > figure > a ul.search-results > li#featured_public_domain_5 > figure > a |
ul.search-results > li#featured_public_domain_6 > figure > a ul.search-results > li#featured_public_domain_6 > figure > a |
ul.search-results > li#featured_public_domain_7 > figure > a ul.search-results > li#featured_public_domain_7 > figure > a |
ul.search-results > li#featured_public_domain_8 > figure > a ul.search-results > li#featured_public_domain_8 > figure > a |
ul.search-results > li#featured_public_domain_9 > figure > a ul.search-results > li#featured_public_domain_9 > figure > a |
ul.search-results > li#featured_public_domain_10 > figure > a ul.search-results > li#featured_public_domain_10 > figure > a |
ul.search-results > li#featured_public_domain_11 > figure > a ul.search-results > li#featured_public_domain_11 > figure > a |
ul.search-results > li#featured_public_domain_12 > figure > a ul.search-results > li#featured_public_domain_12 > figure > a |
These are opportunities to improve the semantics of the controls in your application. This may enhance the experience for users of assistive technology, like a screen reader.
Source maps translate minified code to the original source code. This helps developers debug in production. In addition, Lighthouse is able to provide further insights. Consider deploying source maps to take advantage of these benefits. Learn more about source maps.
Performance issues directly impact user engagement and conversion rates.
These checks ensure that your page is following basic search engine optimization advice. There are many additional factors Lighthouse does not score here that may affect your search ranking, including performance on Core Web Vitals. Learn more about Google Search Essentials.
Send Feedback