C — https://codesandbox.io | BeaverCheck Audit

Site Health

Score: 76 / 100

Based on 8 categories, 0 sections

How is this calculated?

The overall score is a weighted average of individual category scores. Categories with more impact on user experience and security carry more weight.

Performance 25%Security 25%Accessibility 15%SEO 10%Infrastructure 10%Compliance 8%Content 5%Sustainability 2%

Weights reflect general web best practices. Individual needs may differ.

Top Priorities (5)

/.env is publicly accessible

Security › Information Leakage

Content-Security-Policy header is missing

Security › Security Headers

HSTS header is missing

Security › Security Headers

No Content-Security-Policy header found

Security › Content Security Policy

No <main> landmark found

Accessibility › Landmark Structure

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[![BeaverCheck](https://beavercheck.com/badge?url=https%3A%2F%2Fcodesandbox.io)](https://beavercheck.com/results/40247afa-7664-2e18-7e11-1e79b161ef4f)

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Lighthouse Scores

Industry-standard audits powered by Google Lighthouse.

Performance

Accessibility

Best Practices

SEO

Core Web Vitals

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.

1.21 s

Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.

20.85 s

Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.

731 ms

Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.

0.074

Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.

3.83 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.

21.77 s

Detailed Report

Audit breakdown by category with detailed findings.

Performance

Insights

Remove large, duplicate JavaScript modules from bundles to reduce unnecessary bytes consumed by network activity.

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

3rd party code can significantly impact load performance. Reduce and defer loading of 3rd party code to prioritize your page's content.

Consider setting font-display to swap or optional to ensure text is consistently visible. swap can be further optimized to mitigate layout shifts with font metric overrides.

URL	Est Savings
codesandbox.io/_next/static/media/material-symbols-outlined.43ee5b2a.woff2	225 ms

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.

headings: [map[key:source label:Source valueType:source-location] map[granularity:1 key:reflowTime label:Total reflow time valueType:ms]]

items: [map[reflowTime:76.189 source:map[type:text value:[unattributed]]]]

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.

description: [preconnect](https://developer.chrome.com/docs/lighthouse/performance/uses-rel-preconnect/) hints help the browser establish a connection earlier in the page load, saving time when the first request for that origin is made. The following are the origins that the page preconnected to.

title: Preconnected origins

value: no origins were preconnected

description: Add [preconnect](https://developer.chrome.com/docs/lighthouse/performance/uses-rel-preconnect/) hints to your most important origins, but try to use no more than 4.

title: Preconnect candidates

value: No additional origins are good candidates for preconnecting

A long cache lifetime can speed up repeat visits to your page. Learn more about caching.

Request	Cache TTL	Transfer Size
/codesandbox/sandbox-templates/main/codeium/.codesandbox/...	300.0 s	12.9 KiB
codesandbox.io/cdn-cgi/challenge-platform/h/b/scripts/jsd/625261456364/main.js?	14400.0 s	12.5 KiB
/codesandbox/sandbox-templates/main/angular/.codesandbox/...	300.0 s	6.4 KiB
/codesandbox/sandbox-templates/main/react-vite/.codesandb...	300.0 s	6.1 KiB
/codesandbox/sandbox-templates/main/python/.codesandbox/i...	300.0 s	6.0 KiB
/codesandbox/sandbox-templates/main/nextjs/.codesandbox/i...	300.0 s	4.8 KiB
/beacon.min.js/v8c78df7c7c0f484497ecbca7046644da177152312...	86400.0 s	10.7 KiB
/codesandbox/sandbox-templates/main/html-css/.codesandbox...	300.0 s	1.8 KiB
/codesandbox/sandbox-templates/main/docker/.codesandbox/i...	300.0 s	1.3 KiB
/codesandbox/sandbox-templates/main/javascript/.codesandb...	300.0 s	1.1 KiB

Reducing the download time of images can improve the perceived load time of the page and LCP. Learn more about optimizing image size

	URL	Resource Size	Est Savings
Template Icon `a.c-jcHkJJ > div.c-guBENg > div.c-guBENg > img`	/codesandbox/sandbox-templates/main/codeium/.codesandbox/...	12.7 KiB	12.5 KiB
Template Icon `a.c-jcHkJJ > div.c-guBENg > div.c-guBENg > img`	/codesandbox/sandbox-templates/main/angular/.codesandbox/...	5.9 KiB	5.4 KiB
Template Icon `a.c-jcHkJJ > div.c-guBENg > div.c-guBENg > img`	/codesandbox/sandbox-templates/main/python/.codesandbox/i...	5.9 KiB	5.4 KiB
Template Icon `a.c-jcHkJJ > div.c-guBENg > div.c-guBENg > img`	/codesandbox/sandbox-templates/main/react-vite/.codesandb...	5.6 KiB	5.1 KiB

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.

URL	Transfer Size	Duration
codesandbox.io/_next/static/css/572bbcedee2be673.css	4.8 KiB
codesandbox.io/_next/static/css/00c8b2a09ec629c2.css	6.3 KiB	150 ms
codesandbox.io/_next/static/css/b591dbd1e83704ac.css	1.3 KiB

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.

TTI

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.

Diagnostics

Reduce unused JavaScript and defer loading scripts until they are required to decrease bytes consumed by network activity. Learn how to reduce unused JavaScript.

Estimated savings: 1.5 s 317.3 KiB

URL	Transfer Size	Est Savings
codesandbox.io/_next/static/chunks/9230-85da48510973f4ae.js	89.3 KiB	85.3 KiB
codesandbox.io/_next/static/chunks/9331-ab608ee9ae01eddb.js	125.7 KiB	69.0 KiB
codesandbox.io/_next/static/chunks/ec0da940-7fe13e19c1ef37bc.js	50.4 KiB	45.5 KiB
codesandbox.io/_next/static/chunks/2409-a2745fd5e5a7ed70.js	50.0 KiB	36.4 KiB
codesandbox.io/_next/static/chunks/ef9c525d-794586603a2cf360.js	44.5 KiB	34.4 KiB
codesandbox.io/_next/static/chunks/3037-34ebfe82f03e16ac.js	32.5 KiB	24.3 KiB
codesandbox.io/_next/static/chunks/e332d428-607a0fc2b0f712b1.js	33.6 KiB	22.4 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.

URL	Total CPU Time	Script Evaluation	Script Parse
codesandbox.io/	2.7 s	70 ms	4.7 ms
codesandbox.io/_next/static/chunks/7157-f1dd02184197292d.js	837 ms	766 ms	18 ms
codesandbox.io/cdn-cgi/challenge-platform/scripts/jsd/main.js	501 ms	481 ms	2.5 ms
codesandbox.io/_next/static/chunks/3a1fbd1c-9a309fde5120dbc5.js	469 ms	153 ms	21 ms
Unattributable	414 ms	14 ms	0.0 ms
codesandbox.io/_next/static/chunks/app/page-e4cb27a7a3b23bcf.js	207 ms	197 ms	5.3 ms
/beacon.min.js/v8c78df7c7c0f484497ecbca7046644da177152312...	207 ms	36 ms	8.1 ms
codesandbox.io/_next/static/chunks/9331-ab608ee9ae01eddb.js	157 ms	124 ms	32 ms
codesandbox.io/_next/static/chunks/1261-d0847cd35a4e9b63.js	100 ms	86 ms	4.5 ms
codesandbox.io/_next/static/chunks/ef9c525d-794586603a2cf360.js	52 ms	30 ms	21 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

Category	Time Spent
Script Evaluation	2.0 s
Other	1.7 s
Style & Layout	1.3 s
Rendering	554 ms
Script Parsing & Compilation	269 ms
Parse HTML & CSS	68 ms
Garbage Collection	19 ms

Minifying CSS files can reduce network payload sizes. Learn how to minify CSS.

Estimated savings: 0.0 ms 2.3 KiB

URL	Transfer Size	Est Savings
--sxs{--sxs:0 t-dfJADL} …	33.0 KiB	2.3 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.

Estimated savings: 0.0 ms 42.8 KiB

URL	Transfer Size	Est Savings
--sxs{--sxs:0 t-dfJADL} …	32.4 KiB	29.7 KiB
--sxs{--sxs:0 t-dfJADL} …	15.0 KiB	13.0 KiB

Large network payloads cost users real money and are highly correlated with long load times. Learn how to reduce payload sizes.

URL	Transfer Size
codesandbox.io/_next/static/media/material-symbols-outlined.43ee5b2a.woff2	2.9 MiB
codesandbox.io/_next/static/chunks/9331-ab608ee9ae01eddb.js	125.7 KiB
codesandbox.io/_next/static/chunks/9230-85da48510973f4ae.js	89.4 KiB
codesandbox.io/new/fonts/TWKEverett-Medium-web.woff2	59.9 KiB
codesandbox.io/_next/static/chunks/3a1fbd1c-9a309fde5120dbc5.js	52.4 KiB
codesandbox.io/_next/static/chunks/ec0da940-7fe13e19c1ef37bc.js	50.5 KiB
codesandbox.io/_next/static/chunks/2409-a2745fd5e5a7ed70.js	50.1 KiB
codesandbox.io/_next/static/media/e4af272ccee01ff0-s.p.woff2	47.4 KiB
codesandbox.io/_next/static/chunks/ef9c525d-794586603a2cf360.js	44.6 KiB
codesandbox.io/	37.9 KiB

More information about the performance of your application. These numbers don't directly affect the Performance score.

●Layout shift culprits

●Document request latency

●Optimize DOM size

●LCP breakdown

●Modern HTTP

●Optimize viewport for mobile

●Minify JavaScript

●Avoid long main-thread tasks 14 long tasks found

●Avoid non-composited animations 24 animated elements found

●Image elements have explicit `width` and `height`

●Page didn't prevent back/forward cache restoration

●Network Requests

●Network Round Trip Times 20 ms

●Server Backend Latencies 120 ms

●Tasks

●Diagnostics

●Metrics

●Screenshot Thumbnails

●Final Screenshot

●Script Treemap Data

●Resources Summary

●Avoid multiple page redirects

●Initial server response time was short Root document took 70 ms

●Avoid large layout shifts 3 layout shifts found

○INP breakdown

○LCP request discovery

○User Timing marks and measures

Accessibility

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.

Contrast

Low-contrast text is difficult or impossible for many users to read. Learn how to provide sufficient color contrast.

Failing Elements
Software Engineer, React Team `div.c-guBENg > div.c-guBENg > div.c-guBENg > span.c-gTFglp`
Designer Developer, Stripe `div.c-guBENg > div.c-guBENg > div.c-guBENg > span.c-gTFglp`
Senior Software Engineer `div.c-guBENg > div.c-guBENg > div.c-guBENg > span.c-gTFglp`
Co-creator of Astro `div.c-guBENg > div.c-guBENg > div.c-guBENg > span.c-gTFglp`

These are opportunities to improve the legibility of your content.

Navigation

Properly ordered headings that do not skip levels convey the semantic structure of the page, making it easier to navigate and understand when using assistive technologies. Learn more about heading order.

Failing Elements
AI agents `div.c-eeXALW > div.c-guBENg > div.c-guBENg > h4.c-bfvcVA`
0 million+ `div.c-eeXALW > div.c-guBENg > div > h4.c-exFArQ`

These are opportunities to improve keyboard navigation in your application.

○Interactive controls are keyboard focusable

○Interactive elements indicate their purpose and state

○The page has a logical tab order

○Visual order on the page follows DOM order

○User focus is not accidentally trapped in a region

○The user's focus is directed to new content added to the page

○HTML5 landmark elements are used to improve navigation

○Offscreen content is hidden from assistive technology

○Custom controls have associated labels

○Custom controls have ARIA roles

●`[aria-*]` attributes match their roles

●`[aria-hidden="true"]` is not present on the document `<body>`

●`[role]`s have all required `[aria-*]` attributes

●`[role]` values are valid

●`[aria-*]` attributes have valid values

●`[aria-*]` attributes are valid and not misspelled

●Buttons have an accessible name

●Image elements have `[alt]` attributes

●`[user-scalable="no"]` is not used in the `<meta name="viewport">` element and the `[maximum-scale]` attribute is not less than 5.

●ARIA attributes are used as specified for the element's role

●Elements with `role="dialog"` or `role="alertdialog"` have accessible names.

●Elements use only permitted ARIA attributes

●Document has a `<title>` element

●`<html>` element has a `[lang]` attribute

●`<html>` element has a valid value for its `[lang]` attribute

●Links are distinguishable without relying on color.

●Links have a discernible name

●Lists contain only `<li>` elements and script supporting elements (`<script>` and `<template>`).

●List items (`<li>`) are contained within `<ul>`, `<ol>` or `<menu>` parent elements

●No element has a `[tabindex]` value greater than 0

●Touch targets have sufficient size and spacing.

●Document has a main landmark.

●Deprecated ARIA roles were not used

●Identical links have the same purpose.

●Elements with visible text labels have matching accessible names.

○`[accesskey]` values are unique

○`button`, `link`, and `menuitem` elements have accessible names

○`[aria-hidden="true"]` elements do not contain focusable descendents

○ARIA input fields have accessible names

○ARIA `meter` elements have accessible names

○ARIA `progressbar` elements have accessible names

○Elements with an ARIA `[role]` that require children to contain a specific `[role]` have all required children.

○`[role]`s are contained by their required parent element

○Elements with the `role=text` attribute do not have focusable descendents.

○ARIA toggle fields have accessible names

○ARIA `tooltip` elements have accessible names

○ARIA `treeitem` elements have accessible names

○The page contains a heading, skip link, or landmark region

○`<dl>`'s contain only properly-ordered `<dt>` and `<dd>` groups, `<script>`, `<template>` or `<div>` elements.

○Definition list items are wrapped in `<dl>` elements

○ARIA IDs are unique

○No form fields have multiple labels

○`<frame>` or `<iframe>` elements have a title

○`<html>` element has an `[xml:lang]` attribute with the same base language as the `[lang]` attribute.

○Input buttons have discernible text.

○`<input type="image">` elements have `[alt]` text

○Form elements have associated labels

○The document does not use `<meta http-equiv="refresh">`

○`<object>` elements have alternate text

○Select elements have associated label elements.

○Skip links are focusable.

○Cells in a `<table>` element that use the `[headers]` attribute refer to table cells within the same table.

○`<th>` elements and elements with `[role="columnheader"/"rowheader"]` have data cells they describe.

○`[lang]` attributes have a valid value

○`<video>` elements contain a `<track>` element with `[kind="captions"]`

○Tables have different content in the summary attribute and `<caption>`.

○All heading elements contain content.

○Uses ARIA roles only on compatible elements

○Image elements do not have `[alt]` attributes that are redundant text.

○Tables use `<caption>` instead of cells with the `[colspan]` attribute to indicate a caption.

○`<td>` elements in a large `<table>` have one or more table headers.

Best Practices

General

Deprecated APIs will eventually be removed from the browser. Learn more about deprecated APIs.

Deprecation / Warning	Source
SharedStorage	codesandbox.io/cdn-cgi/challenge-platform/scripts/jsd/main.js
StorageType.persistent is deprecated. Please use standardized navigator.storage instead.	codesandbox.io/cdn-cgi/challenge-platform/scripts/jsd/main.js
Fledge	codesandbox.io/cdn-cgi/challenge-platform/scripts/jsd/main.js

Errors logged to the console indicate unresolved problems. They can come from network request failures and other browser concerns. Learn more about this errors in console diagnostic audit

Source	Description
codesandbox.io/_next/static/chunks/7157-f1dd02184197292d.js	`[PostHog.js] PostHog was initialized without a token. This likely indicates a misconfiguration. Please check the first argument passed to posthog.init()`
codesandbox.io/_next/static/chunks/3a1fbd1c-9a309fde5120dbc5.js	Error: Minified React error #422; visit https://reactjs.org/docs/error-decoder.html?invariant=422 for the full message or use the non-minified dev environment for full errors and additional helpful warnings. at https://codesandbox.io/_next/static/chunks/3a1fbd1c-9a309fde5120dbc5.js:1:63867 at lq (https://codesandbox.io/_next/static/chunks/3a1fbd1c-9a309fde5120dbc5.js:1:65218) at iB (https://codesandbox.io/_next/static/chunks/3a1fbd1c-9a309fde5120dbc5.js:1:120510) at o4 (https://codesandbox.io/_next/static/chunks/3a1fbd1c-9a309fde5120dbc5.js:1:94661) at https://codesandbox.io/_next/static/chunks/3a1fbd1c-9a309fde5120dbc5.js:1:90724 at https://codesandbox.io/_next/static/chunks/3a1fbd1c-9a309fde5120dbc5.js:1:90731 at oj (https://codesandbox.io/_next/static/chunks/3a1fbd1c-9a309fde5120dbc5.js:1:90836) at MessagePort.M (https://codesandbox.io/_next/static/chunks/7157-f1dd02184197292d.js:1:80573)
codesandbox.io/_next/static/chunks/3a1fbd1c-9a309fde5120dbc5.js	Error: Minified React error #425; visit https://reactjs.org/docs/error-decoder.html?invariant=425 for the full message or use the non-minified dev environment for full errors and additional helpful warnings. at sD (https://codesandbox.io/_next/static/chunks/3a1fbd1c-9a309fde5120dbc5.js:1:146132) at https://codesandbox.io/_next/static/chunks/3a1fbd1c-9a309fde5120dbc5.js:1:100578 at o5 (https://codesandbox.io/_next/static/chunks/3a1fbd1c-9a309fde5120dbc5.js:1:103422) at o4 (https://codesandbox.io/_next/static/chunks/3a1fbd1c-9a309fde5120dbc5.js:1:94722) at https://codesandbox.io/_next/static/chunks/3a1fbd1c-9a309fde5120dbc5.js:1:90724 at https://codesandbox.io/_next/static/chunks/3a1fbd1c-9a309fde5120dbc5.js:1:90731 at oj (https://codesandbox.io/_next/static/chunks/3a1fbd1c-9a309fde5120dbc5.js:1:90836) at MessagePort.M (https://codesandbox.io/_next/static/chunks/7157-f1dd02184197292d.js:1:80573)
codesandbox.io/api/v1/users/current	`Failed to load resource: the server responded with a status of 401 ()`

●Uses HTTPS

●Avoids third-party cookies

●Allows users to paste into input fields

●Avoids requesting the geolocation permission on page load

●Avoids requesting the notification permission on page load

●Displays images with correct aspect ratio

●Serves images with appropriate resolution

●Page has the HTML doctype

●Properly defines charset

●No issues in the `Issues` panel in Chrome Devtools

●Ensure CSP is effective against XSS attacks

●Use a strong HSTS policy

●Ensure proper origin isolation with COOP

●Mitigate clickjacking with XFO or CSP

●Mitigate DOM-based XSS with Trusted Types

●Page has valid source maps

○Redirects HTTP traffic to HTTPS

○Detected JavaScript libraries

SEO

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.

Content Best Practices

Descriptive link text helps search engines understand your content. Learn how to make links more accessible.

Link destination	Link Text
codesandbox.io/blog/joining-together-ai-introducing-codesandbox-sdk	Learn more

Format your HTML in a way that enables crawlers to better understand your app’s content.

○Structured data is valid

●Page isn’t blocked from indexing

●Document has a `<title>` element

●Document has a meta description

●Page has successful HTTP status code

●Links are crawlable

●robots.txt is valid

●Image elements have `[alt]` attributes

●Document has a valid `hreflang`

○Document has a valid `rel=canonical`

Lighthouse Scores

Industry-standard audits powered by Google Lighthouse. — Desktop

Performance

Accessibility

Best Practices

SEO

Core Web Vitals

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.

621 ms

Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.

4.35 s

Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.

0 ms

Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.

0.008

Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.

924 ms

Time to Interactive Time to Interactive — how long until the page is fully interactive and responds to user input. Under 3.8s is good.

4.35 s

Detailed Report

Audit breakdown by category with detailed findings.

Performance

Insights

Remove large, duplicate JavaScript modules from bundles to reduce unnecessary bytes consumed by network activity.

3rd party code can significantly impact load performance. Reduce and defer loading of 3rd party code to prioritize your page's content.

Consider setting font-display to swap or optional to ensure text is consistently visible. swap can be further optimized to mitigate layout shifts with font metric overrides.

URL	Est Savings
codesandbox.io/_next/static/media/material-symbols-outlined.43ee5b2a.woff2	250 ms

headings: [map[key:source label:Source valueType:source-location] map[granularity:1 key:reflowTime label:Total reflow time valueType:ms]]

items: [map[reflowTime:52.165 source:map[type:text value:[unattributed]]]]

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.

title: Preconnected origins

value: no origins were preconnected

description: Add [preconnect](https://developer.chrome.com/docs/lighthouse/performance/uses-rel-preconnect/) hints to your most important origins, but try to use no more than 4.

title: Preconnect candidates

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.

URL	Transfer Size	Duration
codesandbox.io/_next/static/css/b591dbd1e83704ac.css	1.4 KiB	239 ms
codesandbox.io/_next/static/css/572bbcedee2be673.css	5.0 KiB	239 ms
codesandbox.io/_next/static/css/00c8b2a09ec629c2.css	6.5 KiB	114 ms

A long cache lifetime can speed up repeat visits to your page. Learn more about caching.

Request	Cache TTL	Transfer Size
/codesandbox/sandbox-templates/main/codeium/.codesandbox/...	300.0 s	12.9 KiB
codesandbox.io/cdn-cgi/challenge-platform/h/b/scripts/jsd/625261456364/main.js?	14400.0 s	12.5 KiB
/codesandbox/sandbox-templates/main/python/.codesandbox/i...	300.0 s	6.4 KiB
/codesandbox/sandbox-templates/main/angular/.codesandbox/...	300.0 s	6.1 KiB
/codesandbox/sandbox-templates/main/react-vite/.codesandb...	300.0 s	5.8 KiB
/codesandbox/sandbox-templates/main/nextjs/.codesandbox/i...	300.0 s	4.8 KiB
/beacon.min.js/v8c78df7c7c0f484497ecbca7046644da177152312...	86400.0 s	10.7 KiB
/codesandbox/sandbox-templates/main/html-css/.codesandbox...	300.0 s	1.8 KiB
/codesandbox/sandbox-templates/main/docker/.codesandbox/i...	300.0 s	1.6 KiB
/codesandbox/sandbox-templates/main/javascript/.codesandb...	300.0 s	1.1 KiB

Reducing the download time of images can improve the perceived load time of the page and LCP. Learn more about optimizing image size

	URL	Resource Size	Est Savings
Template Icon `a.c-jcHkJJ > div.c-guBENg > div.c-guBENg > img`	/codesandbox/sandbox-templates/main/codeium/.codesandbox/...	12.7 KiB	12.7 KiB
Template Icon `a.c-jcHkJJ > div.c-guBENg > div.c-guBENg > img`	/codesandbox/sandbox-templates/main/angular/.codesandbox/...	5.9 KiB	5.7 KiB
Template Icon `a.c-jcHkJJ > div.c-guBENg > div.c-guBENg > img`	/codesandbox/sandbox-templates/main/python/.codesandbox/i...	5.9 KiB	5.7 KiB
Template Icon `a.c-jcHkJJ > div.c-guBENg > div.c-guBENg > img`	/codesandbox/sandbox-templates/main/react-vite/.codesandb...	5.6 KiB	5.4 KiB

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.

TTI

Diagnostics

Reduce unused JavaScript and defer loading scripts until they are required to decrease bytes consumed by network activity. Learn how to reduce unused JavaScript.

Estimated savings: 190 ms 316.9 KiB

URL	Transfer Size	Est Savings
codesandbox.io/_next/static/chunks/9230-85da48510973f4ae.js	89.2 KiB	85.2 KiB
codesandbox.io/_next/static/chunks/9331-ab608ee9ae01eddb.js	125.6 KiB	69.0 KiB
codesandbox.io/_next/static/chunks/ec0da940-7fe13e19c1ef37bc.js	50.3 KiB	45.4 KiB
codesandbox.io/_next/static/chunks/2409-a2745fd5e5a7ed70.js	50.0 KiB	36.3 KiB
codesandbox.io/_next/static/chunks/ef9c525d-794586603a2cf360.js	44.5 KiB	34.3 KiB
codesandbox.io/_next/static/chunks/3037-34ebfe82f03e16ac.js	32.5 KiB	24.3 KiB
codesandbox.io/_next/static/chunks/e332d428-607a0fc2b0f712b1.js	33.6 KiB	22.4 KiB

Minifying CSS files can reduce network payload sizes. Learn how to minify CSS.

Estimated savings: 0.0 ms 2.3 KiB

URL	Transfer Size	Est Savings
--sxs{--sxs:0 t-dfJADL} …	33.0 KiB	2.3 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.

Estimated savings: 0.0 ms 41.7 KiB

URL	Transfer Size	Est Savings
--sxs{--sxs:0 t-dfJADL} …	32.4 KiB	29.3 KiB
--sxs{--sxs:0 t-dfJADL} …	15.0 KiB	12.4 KiB

Large network payloads cost users real money and are highly correlated with long load times. Learn how to reduce payload sizes.

URL	Transfer Size
codesandbox.io/_next/static/media/material-symbols-outlined.43ee5b2a.woff2	2.9 MiB
codesandbox.io/_next/static/chunks/9331-ab608ee9ae01eddb.js	125.8 KiB
codesandbox.io/_next/static/chunks/9230-85da48510973f4ae.js	89.5 KiB
codesandbox.io/new/fonts/TWKEverett-Medium-web.woff2	59.9 KiB
codesandbox.io/_next/static/chunks/3a1fbd1c-9a309fde5120dbc5.js	52.5 KiB
codesandbox.io/_next/static/chunks/ec0da940-7fe13e19c1ef37bc.js	50.6 KiB
codesandbox.io/_next/static/chunks/2409-a2745fd5e5a7ed70.js	50.2 KiB
codesandbox.io/_next/static/media/e4af272ccee01ff0-s.p.woff2	47.5 KiB
codesandbox.io/_next/static/chunks/ef9c525d-794586603a2cf360.js	44.7 KiB
codesandbox.io/	37.8 KiB

More information about the performance of your application. These numbers don't directly affect the Performance score.

●Layout shift culprits

●Document request latency

●Optimize DOM size

●LCP breakdown

●Modern HTTP

●Optimize viewport for mobile

●Max Potential First Input Delay 40 ms

●Minify JavaScript

●JavaScript execution time 0.3 s

●Minimizes main-thread work 1.1 s

●Avoid long main-thread tasks 1 long task found

●Avoid non-composited animations 25 animated elements found

●Image elements have explicit `width` and `height`

●Page didn't prevent back/forward cache restoration

●Network Requests

●Network Round Trip Times 20 ms

●Server Backend Latencies 50 ms

●Tasks

●Diagnostics

●Metrics

●Screenshot Thumbnails

●Final Screenshot

●Script Treemap Data

●Resources Summary

●Avoid multiple page redirects

●Initial server response time was short Root document took 80 ms

●Avoid large layout shifts 1 layout shift found

○INP breakdown

○LCP request discovery

○User Timing marks and measures

Accessibility

Contrast

Low-contrast text is difficult or impossible for many users to read. Learn how to provide sufficient color contrast.

Failing Elements
Software Engineer, React Team `div.c-guBENg > div.c-guBENg > div.c-guBENg > span.c-gTFglp`
Designer Developer, Stripe `div.c-guBENg > div.c-guBENg > div.c-guBENg > span.c-gTFglp`
Co-Founder and COO of Blackbox AI `div.c-guBENg > div.c-guBENg > div.c-guBENg > span.c-gTFglp`
Senior Software Engineer `div.c-guBENg > div.c-guBENg > div.c-guBENg > span.c-gTFglp`
Co-creator of Astro `div.c-guBENg > div.c-guBENg > div.c-guBENg > span.c-gTFglp`
Frontend Tech Lead at Adverity `div.c-guBENg > div.c-guBENg > div.c-guBENg > span.c-gTFglp`

These are opportunities to improve the legibility of your content.

Navigation

Failing Elements
AI agents `div.c-eeXALW > div.c-guBENg > div.c-guBENg > h4.c-bfvcVA`
0 million+ `div.c-eeXALW > div.c-guBENg > div > h4.c-exFArQ`

These are opportunities to improve keyboard navigation in your application.

○Interactive controls are keyboard focusable

○Interactive elements indicate their purpose and state

○The page has a logical tab order

○Visual order on the page follows DOM order

○User focus is not accidentally trapped in a region

○The user's focus is directed to new content added to the page

○HTML5 landmark elements are used to improve navigation

○Offscreen content is hidden from assistive technology

○Custom controls have associated labels

○Custom controls have ARIA roles

●`[aria-*]` attributes match their roles

●`[aria-hidden="true"]` is not present on the document `<body>`

●`[role]`s have all required `[aria-*]` attributes

●`[role]` values are valid

●`[aria-*]` attributes have valid values

●`[aria-*]` attributes are valid and not misspelled

●Buttons have an accessible name

●Image elements have `[alt]` attributes

●`[user-scalable="no"]` is not used in the `<meta name="viewport">` element and the `[maximum-scale]` attribute is not less than 5.

●ARIA attributes are used as specified for the element's role

●Elements with `role="dialog"` or `role="alertdialog"` have accessible names.

●Elements use only permitted ARIA attributes

●Document has a `<title>` element

●`<html>` element has a `[lang]` attribute

●`<html>` element has a valid value for its `[lang]` attribute

●Links are distinguishable without relying on color.

●Links have a discernible name

●Lists contain only `<li>` elements and script supporting elements (`<script>` and `<template>`).

●List items (`<li>`) are contained within `<ul>`, `<ol>` or `<menu>` parent elements

●No element has a `[tabindex]` value greater than 0

●Touch targets have sufficient size and spacing.

●Document has a main landmark.

●Deprecated ARIA roles were not used

●Identical links have the same purpose.

●Elements with visible text labels have matching accessible names.

○`[accesskey]` values are unique

○`button`, `link`, and `menuitem` elements have accessible names

○`[aria-hidden="true"]` elements do not contain focusable descendents

○ARIA input fields have accessible names

○ARIA `meter` elements have accessible names

○ARIA `progressbar` elements have accessible names

○Elements with an ARIA `[role]` that require children to contain a specific `[role]` have all required children.

○`[role]`s are contained by their required parent element

○Elements with the `role=text` attribute do not have focusable descendents.

○ARIA toggle fields have accessible names

○ARIA `tooltip` elements have accessible names

○ARIA `treeitem` elements have accessible names

○The page contains a heading, skip link, or landmark region

○`<dl>`'s contain only properly-ordered `<dt>` and `<dd>` groups, `<script>`, `<template>` or `<div>` elements.

○Definition list items are wrapped in `<dl>` elements

○ARIA IDs are unique

○No form fields have multiple labels

○`<frame>` or `<iframe>` elements have a title

○`<html>` element has an `[xml:lang]` attribute with the same base language as the `[lang]` attribute.

○Input buttons have discernible text.

○`<input type="image">` elements have `[alt]` text

○Form elements have associated labels

○The document does not use `<meta http-equiv="refresh">`

○`<object>` elements have alternate text

○Select elements have associated label elements.

○Skip links are focusable.

○Cells in a `<table>` element that use the `[headers]` attribute refer to table cells within the same table.

○`<th>` elements and elements with `[role="columnheader"/"rowheader"]` have data cells they describe.

○`[lang]` attributes have a valid value

○`<video>` elements contain a `<track>` element with `[kind="captions"]`

○Tables have different content in the summary attribute and `<caption>`.

○All heading elements contain content.

○Uses ARIA roles only on compatible elements

○Image elements do not have `[alt]` attributes that are redundant text.

○Tables use `<caption>` instead of cells with the `[colspan]` attribute to indicate a caption.

○`<td>` elements in a large `<table>` have one or more table headers.

Best Practices

General

Deprecated APIs will eventually be removed from the browser. Learn more about deprecated APIs.

Deprecation / Warning	Source
SharedStorage	codesandbox.io/cdn-cgi/challenge-platform/scripts/jsd/main.js
StorageType.persistent is deprecated. Please use standardized navigator.storage instead.	codesandbox.io/cdn-cgi/challenge-platform/scripts/jsd/main.js
Fledge	codesandbox.io/cdn-cgi/challenge-platform/scripts/jsd/main.js

Errors logged to the console indicate unresolved problems. They can come from network request failures and other browser concerns. Learn more about this errors in console diagnostic audit

Source	Description
codesandbox.io/_next/static/chunks/7157-f1dd02184197292d.js	`[PostHog.js] PostHog was initialized without a token. This likely indicates a misconfiguration. Please check the first argument passed to posthog.init()`
codesandbox.io/_next/static/chunks/3a1fbd1c-9a309fde5120dbc5.js	Error: Minified React error #422; visit https://reactjs.org/docs/error-decoder.html?invariant=422 for the full message or use the non-minified dev environment for full errors and additional helpful warnings. at https://codesandbox.io/_next/static/chunks/3a1fbd1c-9a309fde5120dbc5.js:1:63867 at lq (https://codesandbox.io/_next/static/chunks/3a1fbd1c-9a309fde5120dbc5.js:1:65218) at iB (https://codesandbox.io/_next/static/chunks/3a1fbd1c-9a309fde5120dbc5.js:1:120510) at o4 (https://codesandbox.io/_next/static/chunks/3a1fbd1c-9a309fde5120dbc5.js:1:94661) at https://codesandbox.io/_next/static/chunks/3a1fbd1c-9a309fde5120dbc5.js:1:90724 at https://codesandbox.io/_next/static/chunks/3a1fbd1c-9a309fde5120dbc5.js:1:90731 at oj (https://codesandbox.io/_next/static/chunks/3a1fbd1c-9a309fde5120dbc5.js:1:90836) at MessagePort.M (https://codesandbox.io/_next/static/chunks/7157-f1dd02184197292d.js:1:80573)
codesandbox.io/_next/static/chunks/3a1fbd1c-9a309fde5120dbc5.js	Error: Minified React error #425; visit https://reactjs.org/docs/error-decoder.html?invariant=425 for the full message or use the non-minified dev environment for full errors and additional helpful warnings. at sD (https://codesandbox.io/_next/static/chunks/3a1fbd1c-9a309fde5120dbc5.js:1:146132) at https://codesandbox.io/_next/static/chunks/3a1fbd1c-9a309fde5120dbc5.js:1:100578 at o5 (https://codesandbox.io/_next/static/chunks/3a1fbd1c-9a309fde5120dbc5.js:1:103422) at o4 (https://codesandbox.io/_next/static/chunks/3a1fbd1c-9a309fde5120dbc5.js:1:94722) at https://codesandbox.io/_next/static/chunks/3a1fbd1c-9a309fde5120dbc5.js:1:90724 at https://codesandbox.io/_next/static/chunks/3a1fbd1c-9a309fde5120dbc5.js:1:90731 at oj (https://codesandbox.io/_next/static/chunks/3a1fbd1c-9a309fde5120dbc5.js:1:90836) at MessagePort.M (https://codesandbox.io/_next/static/chunks/7157-f1dd02184197292d.js:1:80573)
codesandbox.io/api/v1/users/current	`Failed to load resource: the server responded with a status of 401 ()`

●Uses HTTPS

●Avoids third-party cookies

●Allows users to paste into input fields

●Avoids requesting the geolocation permission on page load

●Avoids requesting the notification permission on page load

●Displays images with correct aspect ratio

●Serves images with appropriate resolution

●Page has the HTML doctype

●Properly defines charset

●No issues in the `Issues` panel in Chrome Devtools

●Ensure CSP is effective against XSS attacks

●Use a strong HSTS policy

●Ensure proper origin isolation with COOP

●Mitigate clickjacking with XFO or CSP

●Mitigate DOM-based XSS with Trusted Types

●Page has valid source maps

○Redirects HTTP traffic to HTTPS

○Detected JavaScript libraries

SEO

Content Best Practices

Descriptive link text helps search engines understand your content. Learn how to make links more accessible.

Link destination	Link Text
codesandbox.io/blog/joining-together-ai-introducing-codesandbox-sdk	Learn more

Format your HTML in a way that enables crawlers to better understand your app’s content.

○Structured data is valid

●Page isn’t blocked from indexing

●Document has a `<title>` element

●Document has a meta description

●Page has successful HTTP status code

●Links are crawlable

●robots.txt is valid

●Image elements have `[alt]` attributes

●Document has a valid `hreflang`

○Document has a valid `rel=canonical`

Browse & Analyze

Learn

Results for https://codesandbox.io

Site Health

Top Priorities (5)

Lighthouse Scores

Core Web Vitals

Detailed Report

Performance

Insights

Diagnostics

Accessibility

Contrast

Navigation

Best Practices

General

SEO

Content Best Practices

Lighthouse Scores

Core Web Vitals

Detailed Report

Performance

Insights

Diagnostics

Accessibility

Contrast

Navigation

Best Practices

General

SEO

Content Best Practices

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