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.
1.82 s
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
9.56 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
531 ms
Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.
0.079
Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.
2.98 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.
9.92 s
Page Load Progression
DThird-Party ImpactAction100% third-party, 0 ms blockingFIX
DJS Execution CostAction2939ms total JS executionFIX
Main Thread Breakdown
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| https://www.ultimate-guitar.com/ | 511ms | 30ms | 5ms | 3rd |
| https://cmp.inmobi.com/tcfv2/61/cmp2ui-en.js | 456ms | 327ms | 40ms | 3rd |
| https://cmp.inmobi.com/tcfv2/cmp2.js?referer=www.ultimate-guitar.com | 443ms | 281ms | 43ms | 3rd |
| Unattributable | 405ms | 39ms | 0ms | 3rd |
| https://www.ultimate-guitar.com/static/public/build/ug_react_mobile_i18n_es6/202604/mobile_shots.6dde8a0b90f8b009c642a39e0282ba06.js | 241ms | 175ms | 20ms | 3rd |
| https://www.ultimate-guitar.com/static/public/build/ug_react_mobile_i18n_es6/202604/vendor.864b78accb7db9bc62b6720eb6288b8a.js | 213ms | 119ms | 6ms | 3rd |
| https://www.ultimate-guitar.com/cdn-cgi/challenge-platform/scripts/jsd/main.js | 208ms | 198ms | 2ms | 3rd |
| https://www.ultimate-guitar.com/static/public/build/ug_i18n_es6/202604/8699.066b1ecaca85e6c2753c5d030faab610.js | 195ms | 165ms | 1ms | 3rd |
| https://www.ultimate-guitar.com/static/public/build/ug_i18n_es6/202604/index_mobile.249f5a116ba5f12d54e22f8bce071db1.js | 176ms | 141ms | 17ms | 3rd |
| https://www.ultimate-guitar.com/static/public/build/ug_react_mobile_i18n_es6/202604/1423.fbe75486fb520a5ae52beae95e4b1b10.js | 92ms | 69ms | 1ms | 3rd |
FHTTP CachingActionNo cache headersFIX
No Cache-Control header
Adding a Cache-Control header can significantly improve repeat-visit performance.
BPage Weight Budget1.2 MB transferred, 87 requestsREVIEW
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
CImage OptimizationAction43 images, 0 KB saveableREVIEW
Set explicit width and height to prevent CLS.
Performance issues directly impact user engagement and conversion rates.
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
CJS BundlesAction21 scripts, 214 KB unusedREVIEW
Downloaded but never executed on this page.
| Script | Size | Unused | Minified | Party |
|---|---|---|---|---|
| https://cmp.inmobi.com/tcfv2/cmp2.js?referer=www.ultimate-guitar.com | 133 KB | 67 KB (51%) | ✓ | 3rd |
| https://cmp.inmobi.com/tcfv2/61/cmp2ui-en.js | 125 KB | 60 KB (48%) | ✓ | 3rd |
| https://www.ultimate-guitar.com/static/public/build/ug_i18n_es6/202604/index_mobile.249f5a116ba5f12d54e22f8bce071db1.js | 84 KB | 54 KB (65%) | ✓ | 3rd |
| https://www.ultimate-guitar.com/static/public/build/ug_react_mobile_i18n_es6/202604/mobile_shots.6dde8a0b90f8b009c642a39e0282ba06.js | 94 KB | 33 KB (35%) | ✓ | 3rd |
| https://www.ultimate-guitar.com/static/public/build/ug_i18n_es6/202604/179.0f185b2152f6671eb078816dba6f1d03.js | 4 KB | — | ✓ | 3rd |
| https://www.ultimate-guitar.com/static/public/build/ug_i18n_es6/202604/8699.066b1ecaca85e6c2753c5d030faab610.js | 4 KB | — | ✓ | 3rd |
| https://www.ultimate-guitar.com/static/public/build/ug_react_mobile_i18n_es6/202604/9476.f064babf9797608efe291d1602ecfbb0.js | 5 KB | — | ✓ | 3rd |
| https://www.ultimate-guitar.com/static/public/build/ug_react_mobile_i18n_es6/202604/4832.8cae4c71d082b939fcdcfc28c419f5f0.js | 5 KB | — | ✓ | 3rd |
| https://www.ultimate-guitar.com/static/public/build/ug_i18n_es6/202604/9476.5835ffd73c368c385eede1a2b0d561b8.js | 6 KB | — | ✓ | 3rd |
| https://www.ultimate-guitar.com/static/public/build/ug_i18n_es6/202604/4832.6c90de87e8190ba7dfe1d59892475001.js | 5 KB | — | ✓ | 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
CPage Weight InventoryAction87 resources · 1.2 MB · 214 KB savings availableREVIEW
~214.2 KiB of savings available
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 87 resources | 1.2 MiB | ||||||
A+Text CompressionAll text resources are compressedPASS
A+Font LoadingNo web fonts (system fonts)PASS
A+Resource CachingAll resources properly cachedPASS
A+Critical Rendering PathNo render-blocking resourcesPASS
A+Resource HintsNo optimization neededPASS
A+Render-Blocking ResourcesNo render-blocking resources detectedPASS
A+Third-Party ResourcesNo third-party resources detectedPASS
A+Green HostingWhether the site is served from green-energy infrastructurePASS
Green Hosting
This site is hosted on green energy infrastructure
Provider: Cloudflare
Network Waterfall87 requests over 1798msINFO
Third-Party Script CostPer-script blocking time, transfer cost, and cache headersINFO
| Script | Category | Execution | Transfer | Unused | Monthly Cost | Verdict |
|---|---|---|---|---|---|---|
www.ultimate-guitar.com www.ultimate-guitar.com | Other | 511ms | 29 KB | — | $7/mo | Costly |
cmp.inmobi.com cmp.inmobi.com | Other | 456ms | 125 KB | 48% | $6/mo | Costly |
cmp.inmobi.com cmp.inmobi.com | Other | 443ms | 133 KB | 51% | $6/mo | Costly |
Unattributable Unattributable | Other | 405ms | 0 KB | — | $5/mo | Costly |
www.ultimate-guitar.com www.ultimate-guitar.com | Other | 241ms | 94 KB | 35% | $3/mo | Costly |
www.ultimate-guitar.com www.ultimate-guitar.com | Other | 213ms | 33 KB | — | $3/mo | Costly |
www.ultimate-guitar.com www.ultimate-guitar.com | Other | 208ms | 0 KB | — | $3/mo | Costly |
www.ultimate-guitar.com www.ultimate-guitar.com | Other | 195ms | 4 KB | — | $3/mo | Optional |
www.ultimate-guitar.com www.ultimate-guitar.com | Other | 176ms | 84 KB | 65% | $2/mo | Optional |
www.ultimate-guitar.com www.ultimate-guitar.com | Other | 92ms | 4 KB | — | $1/mo | Optional |
These scripts may cost more than they're worth
- www.ultimate-guitar.com adds 511ms and costs ~$7/month
- cmp.inmobi.com adds 456ms and costs ~$6/month
- cmp.inmobi.com adds 443ms and costs ~$6/month
- Unattributable adds 405ms and costs ~$5/month
- www.ultimate-guitar.com adds 241ms and costs ~$3/month
- www.ultimate-guitar.com adds 213ms and costs ~$3/month
- www.ultimate-guitar.com adds 208ms 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
www.ultimate-guitar.com takes 511ms 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.inmobi.com takes 456ms 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.inmobi.com takes 443ms 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 cmp.inmobi.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
Unattributable takes 405ms 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.ultimate-guitar.com takes 241ms 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.ultimate-guitar.com takes 213ms 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.ultimate-guitar.com takes 208ms 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
65% of www.ultimate-guitar.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