Performance
· 15 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.Performance-focused optimization plan with CWV assessment, top offenders, and time estimates
First Contentful Paint First Contentful Paint — how long until the browser renders the first piece of content. Under 1.8s is good.
2.16 s
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
2.84 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
1.43 s
Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.
0.010
Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.
8.27 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.
20.59 s
Page Load Progression
2.3 s
4.5 s
6.8 s
9.0 s
11.3 s 13.6 s 15.8 s
18.1 sFPage Weight BudgetAction21.9 MB transferred, 496 requestsFIX
Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.
JavaScript bundle is large — code-split routes and lazy-load off-screen components to defer.
Source: web.dev
Convert images to WebP/AVIF and resize to display dimensions to reduce transfer size.
Image bandwidth is high — modern formats (WebP/AVIF) and resizing typically cut it 50%+.
Source: web.dev
Subset fonts to include only used characters, or switch to system font stacks.
Font payload is large — subset to used glyphs only, or fall back to system fonts (zero load time).
Source: web.dev font loading
Remove unused CSS rules with tools like PurgeCSS to reduce stylesheet size.
CSS bundle is large — purge unused styles (PurgeCSS, Tailwind JIT) to reduce CSS payload.
Source: web.dev
Each request adds latency. Bundle small files, use sprites, or eliminate unnecessary requests.
High HTTP request count — bundling, sprite-ing, and HTTP/2 server push can reduce per-request overhead.
Source: web.dev
DThird-Party ImpactAction100% third-party, 0 ms blockingFIX
FJS Execution CostAction13927ms total JS executionFIX
Main Thread Breakdown
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| https://lf-douyin-pc-web.douyinstatic.com/obj/douyin-pc-web/ies/douyin_web/framework.52e66524.js | 3833ms | 3476ms | 8ms | 3rd |
| https://lf-douyin-pc-web.douyinstatic.com/obj/douyin-pc-web/ies/douyin_web/client-entry~4.04e04615.js | 3819ms | 401ms | 8ms | 3rd |
| https://www.douyin.com/ | 2666ms | 152ms | 31ms | 3rd |
| Unattributable | 975ms | 43ms | 0ms | 3rd |
| https://lf-ucenter-web.yhgfb-cn-static.com/obj/passport-fe/lottie-no-amd.js | 559ms | 550ms | 6ms | 3rd |
| https://lf-security.bytegoofy.com/obj/security-secsdk/runtime_bundler_34.js | 434ms | 282ms | 4ms | 3rd |
| https://p-pc-weboff.byteimg.com/tos-cn-i-9r5gewecjs/bdms_1.0.1.19_fix.js | 322ms | 159ms | 4ms | 3rd |
| https://lf-douyin-pc-web.douyinstatic.com/obj/douyin-pc-web/ies/douyin_web/async/81708.18085ed3.js | 312ms | 288ms | 6ms | 3rd |
| https://lf-douyin-pc-web.douyinstatic.com/obj/passport-fe/ucenter_fe/@byted/uc-secure-dtrait-core/1.0.31/dist/index.umd.production.js | 298ms | 225ms | 4ms | 3rd |
| https://lf-douyin-pc-web.douyinstatic.com/obj/douyin-pc-web/ies/douyin_web/client-entry~33cb90b2.c2629f46.js | 234ms | 225ms | 8ms | 3rd |
Showing top 10 of 15 scripts
FJS BundlesAction166 scripts, 3.9 MB unusedFIX
Downloaded but never executed on this page.
| Script | Size | Unused | Minified | Party |
|---|---|---|---|---|
| https://lf-douyin-pc-web.douyinstatic.com/obj/douyin-pc-web/ies/douyin_web/async/75032.ef65ae4a.js | 220 KB | 218 KB (100%) | ✓ | 3rd |
| https://lf-douyin-pc-web.douyinstatic.com/obj/douyin-pc-web/ies/douyin_web/26031.93556802.js | 222 KB | 166 KB (75%) | ✓ | 3rd |
| https://lf-douyin-pc-web.douyinstatic.com/obj/douyin-pc-web/ies/douyin_web/async/routes-route.ea5b1689.js | 137 KB | 135 KB (100%) | ✓ | 3rd |
| https://lf-douyin-pc-web.douyinstatic.com/obj/douyin-pc-web/ies/douyin_web/player-8.3b34dad4.js | 131 KB | 109 KB (84%) | ✓ | 3rd |
| https://lf-douyin-pc-web.douyinstatic.com/obj/douyin-pc-web/ies/douyin_web/client-entry~798b6a67.c3afba5f.js | 268 KB | 95 KB (36%) | ✓ | 3rd |
| https://lf-douyin-pc-web.douyinstatic.com/obj/douyin-pc-web/ies/douyin_web/73481.3896da26.js | 112 KB | 86 KB (78%) | ✓ | 3rd |
| https://lf-douyin-pc-web.douyinstatic.com/obj/douyin-pc-web/ies/douyin_web/client-entry~ca98720c.c3c5df70.js | 157 KB | 85 KB (55%) | ✓ | 3rd |
| https://lf-douyin-pc-web.douyinstatic.com/obj/douyin-pc-web/ies/douyin_web/client-entry~8e09d0dc.d528572c.js | 167 KB | 83 KB (51%) | ✓ | 3rd |
| https://lf-douyin-pc-web.douyinstatic.com/obj/douyin-pc-web/ies/douyin_web/client-entry~33cb90b2.c2629f46.js | 136 KB | 78 KB (58%) | ✓ | 3rd |
| https://lf-douyin-pc-web.douyinstatic.com/obj/douyin-pc-web/ies/douyin_web/lottie.3913fc21.js | 84 KB | 72 KB (86%) | ✓ | 3rd |
Consider code splitting or tree shaking to reduce unused code.
This bundle has high unused code — code-split or tree-shake to ship only what executes.
Source: web.dev / Lighthouse coverage
Consider code splitting or tree shaking to reduce unused code.
This bundle has high unused code — code-split or tree-shake to ship only what executes.
Source: web.dev / Lighthouse coverage
Consider code splitting or tree shaking to reduce unused code.
This bundle has high unused code — code-split or tree-shake to ship only what executes.
Source: web.dev / Lighthouse coverage
Consider code splitting or tree shaking to reduce unused code.
This bundle has high unused code — code-split or tree-shake to ship only what executes.
Source: web.dev / Lighthouse coverage
Consider code splitting or tree shaking to reduce unused code.
This bundle has high unused code — code-split or tree-shake to ship only what executes.
Source: web.dev / Lighthouse coverage
FPage Weight InventoryAction496 resources · 21.9 MB · 3.9 MB savings availableFIX
~3.9 MiB of savings available
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 496 resources | 21.9 MiB | ||||||
FHTTP CachingActionNo cache headersFIX
No Cache-Control header
Adding a Cache-Control header can significantly improve repeat-visit performance.
CImage OptimizationAction81 images, 0 KB saveableREVIEW
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
CGreen HostingActionWhether the site is served from green-energy infrastructureREVIEW
Green Hosting
No green hosting detected
A+Text CompressionAll text resources are compressedPASS
A+Font Loading58 fonts (1766 KB)PASS
Web fonts
58
1766 KB total
Render-blocking
0
of 58
Dominant font-display
swap
Most common across fonts
Font loading timeline
- Subset this font — over 100 KB suggests Latin Extended or full glyph coverage that most pages don't need
- Subset this font — over 100 KB suggests Latin Extended or full glyph coverage that most pages don't need
- Subset this font — over 100 KB suggests Latin Extended or full glyph coverage that most pages don't need
Optimization checklist
- Preload critical fonts (priority=high)
- Use woff2 format for all fonts
- Set font-display to swap, optional, or fallback
- Subset large fonts (≤100 KB each)
Fixing the unchecked items could save ~716 KB and ~1432 ms
A+Resource CachingAll resources properly cachedPASS
A+Critical Rendering PathNo render-blocking resourcesPASS
A+Resource HintsNo optimization neededPASS
Network Waterfall496 requests over 44462msINFO
Third-Party Script CostPer-script blocking time, transfer cost, and cache headersINFO
| Script | Category | Execution | Transfer | Unused | Monthly Cost | Verdict |
|---|---|---|---|---|---|---|
lf-douyin-pc-web.douyinstatic.com lf-douyin-pc-web.douyinstatic.com | Other | 3833ms | 92 KB | 39% | ¥189/mo | Costly |
lf-douyin-pc-web.douyinstatic.com lf-douyin-pc-web.douyinstatic.com | Other | 3819ms | 80 KB | 54% | ¥188/mo | Costly |
www.douyin.com www.douyin.com | Other | 2666ms | 113 KB | — | ¥132/mo | Costly |
Unattributable Unattributable | Other | 975ms | 0 KB | — | ¥48/mo | Costly |
lf-ucenter-web.yhgfb-cn-static.com lf-ucenter-web.yhgfb-cn-static.com | Other | 559ms | 48 KB | 51% | ¥28/mo | Costly |
lf-security.bytegoofy.com lf-security.bytegoofy.com | Other | 434ms | 44 KB | — | ¥21/mo | Costly |
p-pc-weboff.byteimg.com p-pc-weboff.byteimg.com | Other | 322ms | 64 KB | — | ¥16/mo | Costly |
lf-douyin-pc-web.douyinstatic.com lf-douyin-pc-web.douyinstatic.com | Other | 312ms | 91 KB | 46% | ¥15/mo | Costly |
lf-douyin-pc-web.douyinstatic.com lf-douyin-pc-web.douyinstatic.com | Other | 298ms | 68 KB | 33% | ¥15/mo | Costly |
lf-douyin-pc-web.douyinstatic.com lf-douyin-pc-web.douyinstatic.com | Other | 234ms | 136 KB | 58% | ¥12/mo | Costly |
lf-douyin-pc-web.douyinstatic.com lf-douyin-pc-web.douyinstatic.com | Other | 154ms | 35 KB | 61% | ¥8/mo | Optional |
lf-douyin-pc-web.douyinstatic.com lf-douyin-pc-web.douyinstatic.com | Other | 111ms | 65 KB | 54% | ¥5/mo | Optional |
lf-douyin-pc-web.douyinstatic.com lf-douyin-pc-web.douyinstatic.com | Other | 95ms | 58 KB | 40% | ¥5/mo | Optional |
lf-c-flwb.bytetos.com lf-c-flwb.bytetos.com | Other | 58ms | 84 KB | 66% | ¥3/mo | Optional |
lf3-short.ibytedapm.com lf3-short.ibytedapm.com | Other | 57ms | 17 KB | — | ¥3/mo | Optional |
These scripts may cost more than they're worth
- lf-douyin-pc-web.douyinstatic.com adds 3833ms and costs ~¥189/month
- lf-douyin-pc-web.douyinstatic.com adds 3819ms and costs ~¥188/month
- www.douyin.com adds 2666ms and costs ~¥132/month
- Unattributable adds 975ms and costs ~¥48/month
- lf-ucenter-web.yhgfb-cn-static.com adds 559ms and costs ~¥28/month
- lf-security.bytegoofy.com adds 434ms and costs ~¥21/month
- p-pc-weboff.byteimg.com adds 322ms and costs ~¥16/month
- lf-douyin-pc-web.douyinstatic.com adds 312ms and costs ~¥15/month
- lf-douyin-pc-web.douyinstatic.com adds 298ms and costs ~¥15/month
- lf-douyin-pc-web.douyinstatic.com adds 234ms and costs ~¥12/month
100% of JavaScript execution time is spent on third-party scripts. Consider auditing which scripts are essential.
When third-party JS execution time exceeds your own, performance gains from frontend work are capped by code you don't own.
Learn more ▾ ▴
Every millisecond of third-party JS competes with your own for main-thread time. If their share is bigger than yours, optimization on your code base barely moves the needle. Audit, defer, or remove third-parties before further frontend optimization. Use Lighthouse's third-party audit to identify the worst offenders.
Source: web.dev
lf-douyin-pc-web.douyinstatic.com takes 3833ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
lf-douyin-pc-web.douyinstatic.com takes 3819ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
54% of lf-douyin-pc-web.douyinstatic.com's code is unused. The script may be loading features you don't use.
Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.
Source: web.dev
www.douyin.com takes 2666ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
Unattributable takes 975ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
lf-ucenter-web.yhgfb-cn-static.com takes 559ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
51% of lf-ucenter-web.yhgfb-cn-static.com's code is unused. The script may be loading features you don't use.
Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.
Source: web.dev
lf-security.bytegoofy.com takes 434ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
p-pc-weboff.byteimg.com takes 322ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
lf-douyin-pc-web.douyinstatic.com takes 312ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
lf-douyin-pc-web.douyinstatic.com takes 298ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
lf-douyin-pc-web.douyinstatic.com takes 234ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
58% of lf-douyin-pc-web.douyinstatic.com's code is unused. The script may be loading features you don't use.
Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.
Source: web.dev
61% of lf-douyin-pc-web.douyinstatic.com's code is unused. The script may be loading features you don't use.
Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.
Source: web.dev
54% of lf-douyin-pc-web.douyinstatic.com's code is unused. The script may be loading features you don't use.
Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.
Source: web.dev
66% of lf-c-flwb.bytetos.com's code is unused. The script may be loading features you don't use.
Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.
Source: web.dev