https://xelta.ai/models/video_generation/seedance-2-0-fast-video-generation
Tested 2026-08-24 06:51:29 using Chrome 150.0.7871.46 (runtime settings)
This page is snappy to interact with, visually stable and follows best practices, but slow to paint, weak on user privacy and slow to respond from the server.
Visual metrics
Google Web Vitals
First contentful paint is poor (21.580 s). It is in the Google Web Vitals poor range, slower than 3 seconds.The page has a high time to first byte (TTFB) 6.982 s that you should look into to improve first contentful paint.
The page is using Google Tag Manager, this is a performance risk since non-tech users can add JavaScript to your page.
Largest contentful paint is poor 26.788 s. It is in the Google Web Vitals poor range, slower than 4 seconds.
Timings summary
| Metric | Min | Median | Mean | Max |
|---|---|---|---|---|
| First visual change | 12.346 s | 12.346 s | 12.346 s | 12.346 s |
| Last visual change | 27.048 s | 27.048 s | 27.048 s | 27.048 s |
| Speed index | 23.294 s | 23.294 s | 23.294 s | 23.294 s |
| Visual readiness | 14.702 s | 14.702 s | 14.702 s | 14.702 s |
| Visual complete 85 | 27.048 s | 27.048 s | 27.048 s | 27.048 s |
| Visual complete 95 | 27.048 s | 27.048 s | 27.048 s | 27.048 s |
| Visual complete 99 | 27.048 s | 27.048 s | 27.048 s | 27.048 s |
Run 1 SpeedIndex median
The red band on the timeline marks when the main thread was busy with long tasks: moments when the page could not paint or respond, however the video looks.
Download videoUse --filmstrip.showAll to show all filmstrips.
Click a frame to seek the video to that moment. The dot marks frames where the page changed visually.
The server dominated the wait. The first byte took 6.982 s (32 % of the time to First Contentful Paint). Nothing can render before it arrives, and Google Web Vitals considers a TTFB over 800 ms in need of improvement. See the request timing on the Waterfall tab. First paint landed at 21.580 s; the 2 render-blocking requests were done by 12.225 s and the remaining ~9.355 s is style, layout and web-font loading. The largest paint followed at 26.788 s.
Want to see how much CSS style-recalculation work delayed FCP and LCP, plus CPU long tasks? Run with --cpu.
Blocking requests delay both paints: the browser renders nothing until they arrive, so they push First Contentful Paint and everything after it, including the largest paint (LCP). Requests that block the parser inside the body stall everything after them in the document. Load JavaScript with defer or async, and keep non-critical CSS off the critical path with media attributes. Bars show when each request loaded on a clock that runs to the last paint (the dashed line is FCP, the clock ends at LCP); the gap after the bars is style and layout work. Web fonts are context, not blockers: text renders invisible or in a fallback face while they load, so a font finishing after a paint is the classic reason text changed late.
| Request | When it loaded | Transfer | Download |
|---|---|---|---|
document | 7.082 s | 23.2 KB | 7.080 s |
145xyk44994b_.cssblocking | 5.182 s | 76.7 KB | 5.182 s |
08ak-dq81l91~.cssblocking | 5.180 s | 1021 B | 5.180 s |
7.063 s | 47.7 KB | 7.063 s | |
06.697 s13.394 sFCP 21.580 sLCP 26.788 s |
The coach helps you find performance problems on your web page using web performance best practice rules. And gives you advice on privacy and best practices. Tested using Coach-core version 9.2.1.
firstContentfulPaintFirst contentful paint is poor (21.580 s). It is in the Google Web Vitals poor range, slower than 3 seconds.The page has a high time to first byte (TTFB) 6.982 s that you should look into to improve first contentful paint.
The First Contentful Paint (FCP) metric measures the time from when the page starts loading to when any part of the page content is rendered on the screen. For this metric, "content" refers to text, images (including background images), <svg> elements, or non-white <canvas> elements.
googleTagManagerThe page is using Google Tag Manager, this is a performance risk since non-tech users can add JavaScript to your page.
Google Tag Manager makes it possible for non tech users to add scripts to your page that will downgrade performance.
largestContentfulPaintLargest contentful paint is poor 26.788 s. It is in the Google Web Vitals poor range, slower than 4 seconds.
Largest contentful paint is one of Google Web Vitals and reports the render time of the largest image or text block visible within the viewport, relative to when the page first started loading. To be fast according to Google, it needs to render before 2.5 seconds and results over 4 seconds is poor performance.
javascriptSizeThe total JavaScript transfer size is 771.7 kB and the uncompressed size is 2.5 MB. This is totally crazy! There is really room for improvement here.
A lot of JavaScript often means you are downloading more than you need. How complex is the page and what can the user do on the page? Do you use multiple JavaScript frameworks?
cssSizeThe total CSS transfer size is 79.5 kB and uncompressed size is 600.4 kB. That is big and the CSS could most probably be smaller.
Delivering a massive amount of CSS to the browser is not the best thing you can do, because it means more work for the browser when parsing the CSS against the HTML and that makes the rendering slower. Try to send only the CSS that is used on that page. And make sure to remove CSS rules when they aren't used anymore.
| URL | Transfer | Content |
|---|---|---|
| https://xelta.ai/_next/static/chunks/145xyk44994b_.css | 76.7 KB | 584.4 KB |
| https://xelta.ai/_next/static/chunks/08ak-dq81l91~.css | 1021 B | 2.0 KB |
longTasksThe page has 2 CPU long tasks with the total of 140 ms. The total blocking time is 10 ms and 1 long task before first contentful paint with total time of 80 ms. However the CPU Long Task is depending on the computer/phones actual CPU speed, so you should measure this on the same type of the device that your user is using. Use Geckoprofiler for Firefox or Chromes tracelog to debug your long tasks.
Long CPU tasks locks the thread. To the user this is commonly visible as a "locked up" page where the browser is unable to respond to user input; this is a major source of bad user experience on the web today. However the CPU Long Task is depending on the computer/phones actual CPU speed, so you should measure this on the same type of the device that your user is using. To debug you should use the Chrome timeline log and drag/drop it into devtools or use Firefox Geckoprofiler.
cacheHeadersThe page has 3 requests that are missing a cache time. Configure a cache time so the browser doesn't need to download them every time. It will save 6.1 kB the next access.
The easiest way to make your page fast is to avoid doing requests to the server. Setting a cache header on your server response will tell the browser that it doesn't need to download the asset again during the configured cache time! Always try to set a cache time if the content doesn't change for every request.
cacheHeadersLongThe page has 11 requests that have a shorter cache time than one year (but still a cache time).
Setting a cache header is good. Setting a long cache header (a year) is even better because the asset will stay in the browser cache across visits. For content-hashed URLs (e.g. app.4af2.css) you can safely use Cache-Control: max-age=31536000, immutable. For unversioned URLs that may change, use a revalidating strategy instead.
optimalCssSizehttps://xelta.ai/_next/static/chunks/145xyk44994b_.css size is 78.5 kB (78518) and that is bigger than the limit of 25 kB. Try to keep each CSS response under 25 kB.
Render-blocking CSS holds up the first paint until it has fully downloaded, parsed and applied, so smaller CSS files mean a faster start. Split your CSS into a small critical bundle inlined or eagerly loaded, with the rest lazy-loaded.
| URL | Transfer | Content |
|---|---|---|
| https://xelta.ai/_next/static/chunks/145xyk44994b_.css | 76.7 KB | 584.4 KB |
privateAssetsThe page has 2 requests with private headers. The main page has a private header. It could be right in some cases where the user can be logged in and served specific content. But if your asset is static it should never be private. Make sure that the assets really should be private and only used by one user. Otherwise, make it cacheable for everyone.
If you set private headers on content, that means that the content are specific for that user. Static content should be able to be cached and used by everyone. Avoid setting the cache header to private.
inlineCssThe page has both inline CSS and CSS requests even though it uses a HTTP/2-ish connection. If you have many users on slow connections, it can be better to only inline the CSS. Run your own tests and check the waterfall graph to see what happens.
In the early days of the Internet, inlining CSS was one of the ugliest things you can do. That has changed if you want your page to start rendering fast for your user. Always inline the critical CSS when you use HTTP/1 and HTTP/2 (avoid doing CSS requests that block rendering) and lazy load and cache the rest of the CSS. It is a little more complicated when using HTTP/2. Does your server support HTTP push? Then maybe that can help. Do you have a lot of users on a slow connection and are serving large chunks of HTML? Then it could be better to use the inline technique, becasue some servers always prioritize HTML content over CSS so the user needs to download the HTML first, before the CSS is downloaded.
mimeTypesThe page has 1 misconfigured mime type.
It's not a great idea to let browsers guess content types (content sniffing), in some cases it can actually be a security risk.
unnecessaryHeadersThere are 1 response that sets both a max-age and expires header. There are 50 responses that sets a server header.
Do not send headers that you don't need. We look for p3p, cache-control and max-age, pragma, server and x-frame-options headers. Have a look at Andrew Betts - Headers for Hackers talk as a guide https://www.youtube.com/watch?v=k92ZbrY815c or read https://www.fastly.com/blog/headers-we-dont-want.
longHeadershttps://xelta.ai/ico...le-touch-icon.png has a header report-to that is 607 characters long. https://xelta.ai/_ne...ta.ai/_next/image has a header report-to that is 609 characters long.
Do not send response headers that are too long.
gaThe page is using Google Analytics meaning you share your users private information with Google. You should use analytics that care about user privacy, something like https://matomo.org.
Google Analytics share private user information with Google that your user hasn't agreed on sharing.
surveillanceThe page embeds 3 resources from companies that profit from user surveillance. Consider privacy-respecting alternatives.
Embedding scripts or iframes from companies whose business model is surveillance capitalism (Google, Facebook, etc.) leaks detailed user data on every page view, often before the user has had a chance to consent. See https://en.wikipedia.org/wiki/Surveillance_capitalism for background. Prefer privacy-respecting alternatives where possible.
contentSecurityPolicyHeaderSet a Content-Security-Policy header to mitigate cross-site scripting attacks. You can start with a Content-Security-Policy-Report-Only header, which only reports violations rather than blocking them.
A Content-Security-Policy response header tells the browser which sources of script, style, and other content are allowed. The most effective form is a strict CSP using nonces or hashes together with strict-dynamic; the worst is a missing header, with unsafe-inline and unsafe-eval close behind. https://web.dev/articles/strict-csp
crossOriginEmbedderPolicyHeaderSet a Cross-Origin-Embedder-Policy header (typically require-corp or credentialless) on the document response to control cross-origin embedding.
Cross-Origin-Embedder-Policy (COEP) makes the page refuse to load cross-origin subresources unless they explicitly opt in via CORP or CORS. Together with Cross-Origin-Opener-Policy it puts the page in a cross-origin isolated context, which mitigates cross-window side-channel attacks (Spectre) and unlocks high-resolution timers and SharedArrayBuffer. https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Cross-Origin-Embedder-Policy
crossOriginOpenerPolicyHeaderSet a Cross-Origin-Opener-Policy header (typically same-origin) on the document response to isolate the page from cross-origin windows.
Cross-Origin-Opener-Policy (COOP) lets a page sever its window-group ties to cross-origin documents that opened it or that it opens. Together with Cross-Origin-Embedder-Policy it puts the page in a cross-origin isolated context, which mitigates cross-window side-channel attacks (Spectre) and unlocks high-resolution timers and SharedArrayBuffer. https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Cross-Origin-Opener-Policy
crossOriginResourcePolicyHeaderSet a Cross-Origin-Resource-Policy header (same-origin, same-site or cross-origin) on the document response to limit who may embed it.
Cross-Origin-Resource-Policy (CORP) is a per-response opt-in that tells the browser which origins are allowed to embed the resource. It blocks cross-origin or cross-site no-cors embedding (img, script, iframe, etc.) and is one of the building blocks of cross-origin isolation. https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Cross-Origin-Resource-Policy
permissionsPolicyHeaderSet a Permissions-Policy header to control which browser features the page can use.
The Permissions-Policy response header (the successor to Feature-Policy) lets a site explicitly opt in or out of powerful browser features such as camera, microphone, geolocation, payment and clipboard. Setting a strict policy reduces the attack surface and limits what embedded third parties can do. https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Permissions-Policy
thirdPartyPrivacyThe page has 4% requests that are 3rd party (2 requests with a size of 198.9 kB). The page also have request to companies that harvest data from users and do not respect users privacy (see https://en.wikipedia.org/wiki/Surveillance_capitalism). The page do 1 tag-manager request and uses 1 tag-manager tool. The page do 1 survelliance request and uses 1 survelliance tool. The page do 1 surveillance request and uses 1 surveillance tool. The page do 1 utility request and uses 1 utility tool.
Using third party requests shares user information with that third party. Please avoid that! The project https://github.com/patrickhulce/third-party-web is used to categorize first/third party requests.
A snapshot of what the browser actually built for this page: the document, how big and deep the DOM tree is and what it kept in storage. Big, deep trees are slower to style and lay out, so the counts Chrome warns about carry a flag.
Document
What the page says it is and how large it rendered.
DOM structure
How much markup the browser has to build, style and lay out.
Storage and connection
What the page stored on the client, and the network it was tested on.
Data collected using
Coach-core version 9.2.1. With updated code from
Webappanalyzer 2026-05-04. Use
--browsertime.firefox.includeResponseBodies html or
--browsertime.chrome.includeResponseBodies html to help Wappalyzer find more information about technologies used.
Data collected using Third Party Web version 0.29.2.
Data from run 1
0.0s13.7s16.2s17.6s22.8s24.2s25.7s27.1sWhen the page main content is rendered, collected via the Largest Contentful Paint API. Read more about Largest Contentful Paint.
body > div#app-root > header > div > div:eq(2) > div > button:eq(1) > span
The LCP element is highlighted in the screenshot. If nothing is highlighted the element was removed before the screenshot or the LCP API couldn't find it.
How much the page's content shifts as it loads, collected via the Cumulative Layout Shift API.
Sorted by individual shift score (higher = bigger shift). The top entries usually account for most of the page's CLS.
body > div#app-root > div:eq(2)body > div#app-root > div:eq(2),body > div#app-root > div:eq(2) > divbody > div#app-root > div:eq(2)body > div#app-root > div:eq(2),body > div#app-root > div:eq(2) > divbody > div#app-root > div:eq(2)body > div#app-root > div:eq(2)body > div#app-root > div:eq(2),body > div#app-root > div:eq(2) > divbody > div#app-root > div:eq(2)body > div#app-root > div:eq(2)body > div#app-root > div:eq(2),body > div#app-root > div:eq(2) > divbody > div#app-root > div:eq(2) > divbody > div#app-root > div:eq(2) > divbody > div#app-root > header > div > div:eq(2)
Elements that shifted by more than 0.01 are highlighted in the screenshot. If an element shifted outside the viewport, it won't appear here. Check the video or filmstrip to see the shift.
Timing data the server chose to expose through Server-Timing response headers on the main document — typically backend time, cache status or experiment flags.
| Name | Duration | Description |
|---|---|---|
cfCacheStatus | 0 ms | MISS |
cfEdge | 363 ms | – |
cfOrigin | 47 ms | – |
There are no custom configured scripts.
There are no custom extra metrics from scripting.
How the page is built.
https://xelta.ai/models/video_generation/seedance-2-0-fast-video-generation
| Header | Value |
|---|---|
alt-svc | h3=":443"; ma=86400 |
cache-control | private, max-age=604800, must-revalidate |
cf-cache-status | MISS |
cf-ray | a3006df96c93a6f9-DEL |
content-encoding | br |
content-type | text/html; charset=utf-8 |
date | Mon, 24 Aug 2026 06:51:38 GMT |
expect-ct | max-age=86400, enforce |
last-modified | Mon, 24 Aug 2026 06:51:38 GMT |
link | </_next/static/media/83afe278b6a6bb3c-s.p.0q-301v4kxxnr.woff2>; rel=preload; as="font"; crossorigin=""; type="font/woff2" |
nel | {"report_to":"cf-nel","success_fraction":0.0,"max_age":604800} |
referrer-policy | same-origin strict-origin-when-cross-origin |
report-to | {"group":"cf-nel","max_age":604800,"endpoints":[{"url":"https://a.nel.cloudflare.com/report/v4?s=jrprR7CHcviHjFNDGWLN8bONcmWFN4uzcQE72w8KRyKQncngNunWXZhwfKwe2K5z8XZx51vPsWE%2FeWmY5WGROZOYgTLeEYy73BPQcCoFltyrURgk1fONcm%2FR"}]} |
server | cloudflare |
server-timing | cfCacheStatus;desc="MISS" cfEdge;dur=363,cfOrigin;dur=47 |
speculation-rules | "/cdn-cgi/speculation" |
strict-transport-security | max-age=31536000; includeSubDomains; preload |
vary | rsc, next-router-state-tree, next-router-prefetch, next-router-segment-prefetch, Accept-Encoding |
x-content-type-options | nosniff |
x-frame-options | SAMEORIGIN |
x-xss-protection | 1; mode=block |
Transfer size963.7 KB
Content size3.4 MB
Requests50
| Content | Header Size | Transfer Size | Content Size | Requests |
|---|---|---|---|---|
| html | 0 b | 23.2 KB | 167.8 KB | 1 |
| css | 0 b | 77.7 KB | 586.3 KB | 2 |
| javascript | 0 b | 753.7 KB | 2.4 MB | 34 |
| image | 0 b | 59.2 KB | 122.6 KB | 8 |
| font | 0 b | 47.7 KB | 47.3 KB | 1 |
| favicon | 0 b | 0 b | 141.5 KB | 1 |
| other | 0 b | 476 B | 151 B | 1 |
| json | 0 b | 1.2 KB | 1.2 KB | 1 |
| plain | 0 b | 573 B | 0 b | 1 |
| Total | 0 b | 963.7 KB | 3.4 MB | 50 |
| Domain | Total download time | Transfer Size | Content Size | Requests |
|---|---|---|---|---|
| xelta.ai | 363.253 s | 769.5 KB | 2.9 MB | 48 |
| www.googletagmanager.com | 13.904 s | 182.9 KB | 551.6 KB | 1 |
| static.cloudflareinsights.com | 9.328 s | 11.3 KB | 30.9 KB | 1 |
| type | min | median | max |
|---|---|---|---|
| Expires | 0 seconds | 1 year | 1 year |
| Last modified | 0 seconds | 1 day | 3 days |
Includes requests done after load event end.
| Content | Transfer Size | Requests |
|---|---|---|
| html | 0 b | 0 |
| css | 0 b | 0 |
| javascript | 0 b | 0 |
| image | 57.8 KB | 7 |
| font | 0 b | 0 |
| favicon | 0 b | 1 |
| plain | 573 B | 1 |
| Total | 58.4 KB | 9 |
Includes requests done after DOM content loaded.
| Content | Transfer Size | Requests |
|---|---|---|
| html | 0 b | 0 |
| css | 0 b | 0 |
| javascript | 0 b | 0 |
| image | 57.8 KB | 7 |
| font | 0 b | 0 |
| favicon | 0 b | 1 |
| plain | 573 B | 1 |
| Total | 58.4 KB | 9 |
--enableProfileRun to see where main-thread time went, blocking time and CPU cost per script, module and function, forced reflows and frame stability. The data is collected in one extra run, so the timing metrics of your measured runs stay untouched.Tasks ≥ 50 ms blocking the main thread, collected via the Long Task API.
A long animation frame (LOAF) is a frame that took ≥ 50 ms from input to the next paint. The part beyond the threshold is blocking time, the number that hurts Interaction to Next Paint and Total Blocking Time. Break long tasks up (scheduler.yield(), smaller chunks) or move the work off the main thread. Read more about the Long Animation Frames API.
| Script | Frames | Time running | Blocking (share by run time) | Forced style & layout | Triggered by |
|---|---|---|---|---|---|
| js3rd party | 1 | 60 ms | 8.8 ms | – | script tag |
| 0y0ijhqmszjlv.js | 2 | 13.6 ms | 1.2 ms | – | event handler |
A frame's blocking time is split between its scripts by their share of the frame's work, capped at each script's own run time — blocking from work no script owns (HTML parsing, browser internals) stays unattributed. The per-script blocking view below uses the same attribution.
The browser did not report which script was responsible for this frame — typically its own style/layout work, or a cross-origin script it will not name.
The browser did not report which script was responsible for this frame — typically its own style/layout work, or a cross-origin script it will not name.
2 more long frames carried no blocking time (nothing ran past the 50 ms threshold) — long, but harmless to INP and TBT.
How much each script blocked the main thread, derived from the Long Animation Frame API. Each frame's blocking time is split between its scripts by their share of the frame's work, capped at each script's own run time — blocking from work no script owns (HTML parsing, browser internals) is not attributed (older data credits the script that started the frame). The closest answer to "which script should I fix to improve TBT" the platform exposes.
Third party requests categorised by Third party web version 0.29.2.
Requests by category3
Transfer size963.7 KB
Content size3.4 MB
Requests50
Calculated using .*xelta.* (use --firstParty to configure).
| Content | Header Size | Transfer Size | Content Size | Requests |
|---|---|---|---|---|
| html | 0 b | 23.2 KB | 167.8 KB | 1 |
| css | 0 b | 77.7 KB | 586.3 KB | 2 |
| javascript | 0 b | 559.4 KB | 1.8 MB | 32 |
| image | 0 b | 59.2 KB | 122.6 KB | 8 |
| font | 0 b | 47.7 KB | 47.3 KB | 1 |
| favicon | 0 b | 0 b | 141.5 KB | 1 |
| other | 0 b | 476 B | 151 B | 1 |
| json | 0 b | 1.2 KB | 1.2 KB | 1 |
| plain | 0 b | 573 B | 0 b | 1 |
| Total | N/A | 769.5 KB | 2.9 MB | 48 |
| Content | Header Size | Transfer Size | Content Size | Requests |
|---|---|---|---|---|
| html | 0 b | 0 b | 0 b | 0 |
| css | 0 b | 0 b | 0 b | 0 |
| javascript | 0 b | 194.2 KB | 582.5 KB | 2 |
| image | 0 b | 0 b | 0 b | 0 |
| font | 0 b | 0 b | 0 b | 0 |
| favicon | 0 b | 0 b | 0 b | 0 |
| Total | N/A | 194.2 KB | 582.5 KB | 2 |