Performance
· 17 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.
3.62 s
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
6.41 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
1.85 s
Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.
0.003
Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.
4.45 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.
19.93 s
Page Load Progression
DPage Weight BudgetAction2.2 MB transferred, 109 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
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 CostAction6664ms total JS executionFIX
Main Thread Breakdown
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| Unattributable | 1000ms | 220ms | 0ms | 3rd |
| https://www.buzzfeed.com/ | 856ms | 10ms | 5ms | 3rd |
| https://www.buzzfeed.com/static-assets/feed-ui/_next/static/chunks/framework-348f86d225132ea3.js | 784ms | 527ms | 14ms | 3rd |
| https://www.buzzfeed.com/static-assets/feed-ui/_next/static/chunks/pages/index-8ca0940eadb29372.js | 636ms | 578ms | 7ms | 3rd |
| https://www.buzzfeed.com/static-assets/feed-ui/_next/static/chunks/281-97afea134b70477e.js | 604ms | 145ms | 5ms | 3rd |
| https://micro.rubiconproject.com/prebid/dynamic/13062.js | 498ms | 441ms | 53ms | 3rd |
| https://www.buzzfeed.com/static-assets/bf-header-ui/buzzfeed/app.f61e19c30d169cacd52a.js | 380ms | 309ms | 50ms | 3rd |
| https://html-load.cc/script/d3d3LmJ1enpmZWVkLmNvbQ.js | 281ms | 234ms | 41ms | 3rd |
| https://client.aps.amazon-adsystem.com/publisher.js | 217ms | 172ms | 30ms | 3rd |
| https://tagan.adlightning.com/buzzfeed/op.js | 188ms | 181ms | 3ms | 3rd |
Showing top 10 of 20 scripts
FJS BundlesAction43 scripts, 759 KB unusedFIX
Downloaded but never executed on this page.
| Script | Size | Unused | Minified | Party |
|---|---|---|---|---|
| https://securepubads.g.doubleclick.net/pagead/managed/js/gpt/m202604200101/pubads_impl.js?cb=31097964 | 188 KB | 136 KB (72%) | ✓ | 3rd |
| https://micro.rubiconproject.com/prebid/dynamic/13062.js | 164 KB | 103 KB (63%) | ✓ | 3rd |
| https://html-load.cc/script/d3d3LmJ1enpmZWVkLmNvbQ.js | 130 KB | 85 KB (66%) | ✓ | 3rd |
| https://www.buzzfeed.com/static-assets/bf-header-ui/buzzfeed/app.f61e19c30d169cacd52a.js | 152 KB | 73 KB (48%) | ✓ | 3rd |
| https://accounts.google.com/gsi/client | 96 KB | 68 KB (71%) | ✓ | 3rd |
| https://www.buzzfeed.com/static-assets/feed-ui/_next/static/chunks/pages/_app-f0d512f6f6b23e56.js | 98 KB | 63 KB (65%) | ✓ | 3rd |
| https://client.aps.amazon-adsystem.com/publisher.js | 82 KB | 50 KB (61%) | ✓ | 3rd |
| https://pagead2.googlesyndication.com/pagead/js/adsbygoogle.js | 0 KB | 35 KB (65%) | ✓ | 3rd |
| https://pagead2.googlesyndication.com/pagead/js/adsbygoogle.js | 0 KB | 35 KB (65%) | ✓ | 3rd |
| https://pagead2.googlesyndication.com/pagead/js/adsbygoogle.js | 54 KB | 35 KB (65%) | ✓ | 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 InventoryAction109 resources · 2.2 MB · 759 KB savings availableFIX
~758.7 KiB of savings available
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 109 resources | 2.2 MiB | ||||||
FHTTP CachingActionNo cache headersFIX
No Cache-Control header
Adding a Cache-Control header can significantly improve repeat-visit performance.
CImage OptimizationAction25 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
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 Loading7 fonts (116 KB)PASS
Web fonts
7
116 KB total
Render-blocking
0
of 7
Dominant font-display
swap
Most common across fonts
Font loading timeline
- Convert to woff2 for ~30% smaller file size
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)
A+Resource CachingAll resources properly cachedPASS
A+Critical Rendering PathNo render-blocking resourcesPASS
A+Resource Hints19 hints, 0 missing preconnectsPASS
Current Resource Hints
19 resource hints configured
A+Render-Blocking ResourcesNo render-blocking resources detectedPASS
A+Third-Party ResourcesNo third-party resources detectedPASS
Network Waterfall109 requests over 1955msINFO
Third-Party Script CostPer-script blocking time, transfer cost, and cache headersINFO
| Script | Category | Execution | Transfer | Unused | Monthly Cost | Verdict |
|---|---|---|---|---|---|---|
Unattributable Unattributable | Other | 1000ms | 0 KB | — | $13/mo | Costly |
www.buzzfeed.com www.buzzfeed.com | Other | 856ms | 294 KB | — | $11/mo | Costly |
www.buzzfeed.com www.buzzfeed.com | Other | 784ms | 42 KB | — | $10/mo | Costly |
www.buzzfeed.com www.buzzfeed.com | Other | 636ms | 16 KB | — | $8/mo | Costly |
www.buzzfeed.com www.buzzfeed.com | Other | 604ms | 20 KB | — | $8/mo | Costly |
micro.rubiconproject.com micro.rubiconproject.com | Other | 498ms | 164 KB | 63% | $7/mo | Costly |
www.buzzfeed.com www.buzzfeed.com | Other | 380ms | 152 KB | 48% | $5/mo | Costly |
html-load.cc html-load.cc | Other | 281ms | 130 KB | 66% | $4/mo | Costly |
client.aps.amazon-adsystem.com client.aps.amazon-adsystem.com | Other | 217ms | 82 KB | 61% | $3/mo | Costly |
tagan.adlightning.com tagan.adlightning.com | Other | 188ms | 11 KB | — | $2/mo | Optional |
securepubads.g.doubleclick.net securepubads.g.doubleclick.net | Other | 185ms | 188 KB | 72% | $2/mo | Optional |
tagan.adlightning.com tagan.adlightning.com | Other | 169ms | 103 KB | — | $2/mo | Optional |
www.buzzfeed.com www.buzzfeed.com | Other | 166ms | 98 KB | 65% | $2/mo | Optional |
pagead2.googlesyndication.com pagead2.googlesyndication.com | Other | 162ms | 0 KB | 65% | $2/mo | Optional |
www.buzzfeed.com www.buzzfeed.com | Other | 161ms | 20 KB | — | $2/mo | Optional |
accounts.google.com accounts.google.com | Other | 94ms | 96 KB | 71% | $1/mo | Optional |
securepubads.g.doubleclick.net securepubads.g.doubleclick.net | Other | 78ms | 34 KB | — | $1/mo | Optional |
www.buzzfeed.com www.buzzfeed.com | Other | 72ms | 122 KB | 65% | $1/mo | Optional |
www.buzzfeed.com www.buzzfeed.com | Other | 70ms | 29 KB | — | $1/mo | Optional |
pub.doubleverify.com pub.doubleverify.com | Other | 63ms | 18 KB | — | $1/mo | Optional |
These scripts may cost more than they're worth
- Unattributable adds 1000ms and costs ~$13/month
- www.buzzfeed.com adds 856ms and costs ~$11/month
- www.buzzfeed.com adds 784ms and costs ~$10/month
- www.buzzfeed.com adds 636ms and costs ~$8/month
- www.buzzfeed.com adds 604ms and costs ~$8/month
- micro.rubiconproject.com adds 498ms and costs ~$7/month
- www.buzzfeed.com adds 380ms and costs ~$5/month
- html-load.cc adds 281ms and costs ~$4/month
- client.aps.amazon-adsystem.com adds 217ms and costs ~$3/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
Unattributable takes 1000ms 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
www.buzzfeed.com takes 856ms 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
www.buzzfeed.com takes 784ms 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
www.buzzfeed.com takes 636ms 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
www.buzzfeed.com takes 604ms 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
micro.rubiconproject.com takes 498ms 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
63% of micro.rubiconproject.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.buzzfeed.com takes 380ms 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
html-load.cc takes 281ms 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
66% of html-load.cc'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
client.aps.amazon-adsystem.com takes 217ms 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
61% of client.aps.amazon-adsystem.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
72% of securepubads.g.doubleclick.net'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
65% of www.buzzfeed.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
65% of pagead2.googlesyndication.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
71% of accounts.google.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
65% of www.buzzfeed.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