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.
2.89 s
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
6.16 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
1.69 s
Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.
0.001
Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.
6.42 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.
10.78 s
Page Load Progression
670 ms 1.3 s 2.0 s 2.7 s 3.3 s 4.0 s
4.7 s
5.4 sFPage Weight BudgetAction6.6 MB transferred, 224 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 CostAction4579ms total JS executionFIX
Main Thread Breakdown
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| https://www.mercurynews.com/_static/??-eJyVj8EKwjAQRH/IdlG07UU8ePHiR4QmNluT3dDdKPbrjYKiF8HjDPOYGbimqmdSRwrqXXQCxYlGmMCiKIwCLIZ4n0U51hGpHmUBH1gKeUASiDRUXsMbK/qg4chWflHJszKdMAS4OLI8QcJe8+Qe1n9gMPNNcHZffUh9yLbcKoueyzzz+ZXYxe2ybdfNqum6zXgHXmRkBw== | 1713ms | 1689ms | 2ms | 3rd |
| https://cmp.osano.com/16A1AnRt2Fn8i1unj/1edc45d9-1a78-48b2-9035-037b31df744a/osano.js | 591ms | 531ms | 5ms | 3rd |
| https://www.mercurynews.com/ | 363ms | 57ms | 3ms | 3rd |
| Unattributable | 322ms | 54ms | 0ms | 3rd |
| https://securepubads.g.doubleclick.net/pagead/managed/js/gpt/m202604170101/pubads_impl.js?cb=31097963 | 211ms | 193ms | 10ms | 3rd |
| https://www.googletagmanager.com/gtm.js?id=GTM-TLFP4R | 157ms | 133ms | 20ms | 3rd |
| https://cdn.adapex.io/hb/aaw.empowerlocal_b.js | 125ms | 110ms | 12ms | 3rd |
| https://htlbid.com/v3/mercurynews.com/htlbid.js?ver=6.9.4 | 121ms | 100ms | 11ms | 3rd |
| https://cdn.p-n.io/pushly-sdk.min.js?domain_key=kxKkF9MK5Eh8oIGD7DDm6lvkHUj6DuIrCOQh&ver=6.9.4 | 112ms | 103ms | 3ms | 3rd |
| https://connext-fd-gnbrate4fjhjb3f7.z01.azurefd.net/index.js | 107ms | 95ms | 1ms | 3rd |
Showing top 10 of 20 scripts
FJS BundlesAction103 scripts, 1.8 MB unusedFIX
Downloaded but never executed on this page.
| Script | Size | Unused | Minified | Party |
|---|---|---|---|---|
| https://engage.mercurynews.com/prod/dfm/t8y9347t.min.js?2026321 | 292 KB | 186 KB (64%) | ✓ | 3rd |
| https://securepubads.g.doubleclick.net/pagead/managed/js/gpt/m202604170101/pubads_impl.js?cb=31097963 | 187 KB | 127 KB (68%) | ✓ | 3rd |
| https://www.mercurynews.com/_static/??-eJyl0MEKwzAIANAfWiIbI6GHset+I2lCMCSuTMP6+bPHngbtQUTRJwjfxcxvkkwCSxsFiaFTMQkL8ogMLEFw3vVsD0g2Dkot28oXOGLoAuVVzjI6jNJy18xnrYGvsAGfPxCjZLMrYqACCVmg6p3tO12j8rM/rt47P7m7u9UfAM2Ivg== | 155 KB | 126 KB (81%) | ✓ | 3rd |
| https://cdn.adapex.io/hb/aaw.empowerlocal_b.js | 178 KB | 112 KB (64%) | ✓ | 3rd |
| https://prodmg2.blob.core.windows.net/newsletterwidget/mngcep/mg2nw.min.js | 144 KB | 110 KB (77%) | ✓ | 3rd |
| https://cds.connatix.com/p/320936758/connatix.player.js | 139 KB | 95 KB (68%) | ✓ | 3rd |
| https://htlbid.com/v3/mercurynews.com/htlbid.js?ver=6.9.4 | 138 KB | 76 KB (55%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-KVX6E4M7J9&l=cswDataLayer&cx=c>m=4e64h1 | 144 KB | 72 KB (50%) | ✓ | 3rd |
| https://accounts.google.com/gsi/client?ver=6.9.4 | 96 KB | 68 KB (71%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtm.js?id=GTM-NFD2QGD&l=MG2DL | 171 KB | 64 KB (37%) | ✓ | 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 InventoryAction224 resources · 6.6 MB · 1.8 MB savings availableFIX
~1.8 MiB of savings available
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 224 resources | 6.6 MiB | ||||||
BImage Optimization45 images, 0 KB saveableREVIEW
CGreen HostingActionWhether the site is served from green-energy infrastructureREVIEW
Green Hosting
No green hosting detected
BHTTP CachingprivateREVIEW
private
| Directive | Value | Meaning |
|---|---|---|
| private | — | Only browser cache, not CDN/proxy |
A+Text CompressionAll text resources are compressedPASS
A+Font Loading7 fonts (235 KB)PASS
Web fonts
7
235 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
- Convert to woff2 for ~30% smaller file size
- 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)
Fixing the unchecked items could save ~23 KB and ~46 ms
A+Resource CachingAll resources properly cachedPASS
A+Critical Rendering PathNo render-blocking resourcesPASS
A+Resource HintsNo optimization neededPASS
Network Waterfall224 requests over 11962msINFO
Third-Party Script CostPer-script blocking time, transfer cost, and cache headersINFO
| Script | Category | Execution | Transfer | Unused | Monthly Cost | Verdict |
|---|---|---|---|---|---|---|
www.mercurynews.com www.mercurynews.com | Other | 1713ms | 10 KB | — | $10/mo | Costly |
cmp.osano.com cmp.osano.com | Other | 591ms | 63 KB | — | $3/mo | Costly |
www.mercurynews.com www.mercurynews.com | Other | 363ms | 42 KB | — | $2/mo | Costly |
Unattributable Unattributable | Other | 322ms | 0 KB | — | $2/mo | Costly |
securepubads.g.doubleclick.net securepubads.g.doubleclick.net | Other | 211ms | 187 KB | 68% | $1/mo | Costly |
Google Tag Manager www.googletagmanager.com | Tag Manager | 157ms | 213 KB | 26% | $1/mo | Optional |
cdn.adapex.io cdn.adapex.io | Other | 125ms | 178 KB | 64% | $1/mo | Optional |
htlbid.com htlbid.com | Other | 121ms | 138 KB | 55% | $1/mo | Optional |
cdn.p-n.io cdn.p-n.io | Other | 112ms | 0 KB | — | $1/mo | Optional |
connext-fd-gnbrate4fjhjb3f7.z01.azurefd.net connext-fd-gnbrate4fjhjb3f7.z01.azurefd.net | Other | 107ms | 3 KB | — | $1/mo | Optional |
Google Tag Manager www.googletagmanager.com | Tag Manager | 107ms | 171 KB | 37% | $1/mo | Optional |
www.mercurynews.com www.mercurynews.com | Other | 95ms | 155 KB | 81% | $1/mo | Optional |
Google Tag Manager www.googletagmanager.com | Tag Manager | 88ms | 159 KB | 39% | $0/mo | Optional |
tagan.adlightning.com tagan.adlightning.com | Other | 82ms | 15 KB | — | $0/mo | Optional |
sdk.mrf.io sdk.mrf.io | Other | 72ms | 63 KB | 40% | $0/mo | Optional |
engage.mercurynews.com engage.mercurynews.com | Other | 71ms | 292 KB | 64% | $0/mo | Optional |
Google Tag Manager www.googletagmanager.com | Tag Manager | 65ms | 145 KB | 42% | $0/mo | Optional |
s.cdn.gcprivacy.net s.cdn.gcprivacy.net | Other | 63ms | 9 KB | — | $0/mo | Optional |
fundingchoicesmessages.google.com fundingchoicesmessages.google.com | Other | 62ms | 70 KB | 54% | $0/mo | Optional |
Google Tag Manager www.googletagmanager.com | Tag Manager | 51ms | 145 KB | 40% | $0/mo | Optional |
These scripts may cost more than they're worth
- www.mercurynews.com adds 1713ms and costs ~$10/month
- cmp.osano.com adds 591ms and costs ~$3/month
- www.mercurynews.com adds 363ms and costs ~$2/month
- Unattributable adds 322ms and costs ~$2/month
- securepubads.g.doubleclick.net adds 211ms and costs ~$1/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
www.mercurynews.com takes 1713ms 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
cmp.osano.com takes 591ms 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.mercurynews.com takes 363ms 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 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
securepubads.g.doubleclick.net takes 211ms 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
68% 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
64% of cdn.adapex.io'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
55% of htlbid.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
81% of www.mercurynews.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
64% of engage.mercurynews.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 fundingchoicesmessages.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