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https://glossier.com

Performance

· 14 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
70
GRADE
C
FIX
5
REVIEW
1
PASS
6
INFO
2

Performance-focused optimization plan with CWV assessment, top offenders, and time estimates

Mobile Desktop
74
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
85
Accessibility Measures how accessible the page is for users with disabilities. Checks color contrast, ARIA labels, and semantic HTML.
77
Best Practices Checks for modern web development best practices including HTTPS, no console errors, and secure JavaScript.
100
SEO Measures basic SEO optimizations: meta tags, crawlability, link text, and mobile friendliness.

First Contentful Paint First Contentful Paint — how long until the browser renders the first piece of content. Under 1.8s is good.

1.25 s

Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.

1.73 s

Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.

114 ms

Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.

0.185

Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.

2.64 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.

7.55 s

Page Load Progression

1.2 s
2.4 s
3.6 s
4.8 s
6.0 s
7.2 s
8.4 s
9.6 s
Checks
14
6 PASS 1 REVIEW 5 FIX
F
Page Weight Budget
Action
14.7 MB transferred, 350 requests
FIX
14.7 MB transferred, 350 requests
Critical::
Page weighs 21.8 MB (14.7 MB transferred)
Warning::
JavaScript is 3.0 MB — consider code splitting or lazy loading
Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.
Got: 3.0 MB
Warning::
350 HTTP requests — consider bundling or reducing
Each request adds latency. Bundle small files, use sprites, or eliminate unnecessary requests.
Info::
Estimated 3.1 g CO2 per page load
14.7 MB / 2.4 MB budget
14.7 MB transferred
350 requests
3.1 g CO2 per page load
Other 9.3 MiB 63%
JavaScript 3.0 MiB 21%
Other 1.2 MiB 8%
Images 645.5 KiB 4%
HTML 160.7 KiB 1%
Fonts 133.7 KiB 1%
Other 113.1 KiB 1%
Other 87.8 KiB 1%
CSS 50.0 KiB 0%
Other 16.6 KiB 0%
Other 0 B 0%
0 2.4 MB 4.9 MB
Over budget

Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.

Why this matters

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.

Why this matters

High HTTP request count — bundling, sprite-ing, and HTTP/2 server push can reduce per-request overhead.

Source: web.dev

D
Third-Party Impact
Action
100% third-party, 0 ms blocking
FIX
100% third-party, 0 ms blocking
Warning::
Third-party code accounts for 100% of page weight (14.7 MiB of 14.7 MiB)
Info::
Third-party blocking time is low (0 ms)
100%
First-party Third-party
D
JS Execution Cost
Action
3359ms total JS execution
FIX
3359ms total JS execution
Warning::
Unattributable: 553ms CPU time
Warning::
https://www.glossier.com/en-es: 472ms CPU time
Warning::
https://www.glossier.com/cdn/wpm/b0e8c7c7aw41bd75a...: 447ms CPU time
Warning::
https://edge.fullstory.com/s/fs.js: 308ms CPU time
Info::
https://www.glossier.com/cdn/shop/t/1393/assets/ap...: 246ms CPU time
Warning::
Third-party scripts: 3359ms (100% of total)

Main Thread Breakdown

Script Evaluation 58% Other 21% Style & Layout 12% Script Parsing & Compilation 5%
ScriptTotalScriptingParse/CompileParty
Unattributable553ms69ms0ms3rd
https://www.glossier.com/en-es472ms83ms5ms3rd
https://www.glossier.com/cdn/wpm/b0e8c7c7aw41bd75a1p837d7fd4m8b145375m.js447ms255ms5ms3rd
https://edge.fullstory.com/s/fs.js308ms236ms6ms3rd
https://www.glossier.com/cdn/shop/t/1393/assets/app.min.js?v=116494217122873023101774881013246ms99ms17ms3rd
https://cdn.optimizely.com/js/22916101539.js234ms181ms10ms3rd
https://21bd15724800.cdn4.forter.com/sn/21bd15724800/script.js190ms172ms15ms3rd
https://onsite.joinground.com/ground.js164ms150ms4ms3rd
https://www.googletagmanager.com/gtm.js?id=GTM-KW9HP9Z137ms124ms11ms3rd
https://7ce243a1e1a2.cdn4.forter.com/sn/7ce243a1e1a2/script.js108ms94ms11ms3rd

Showing top 10 of 17 scripts

F
JS Bundles
Action
179 scripts, 1009 KB unused
FIX
179 scripts, 1009 KB unused
Warning::
https://7ce243a1e1a2.cdn4.forter.com/sn/7ce243a1e1...: 92 KB unused (42%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://21bd15724800.cdn4.forter.com/sn/21bd157248...: 84 KB unused (39%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://21bd15724800.cdn4.forter.com/sn/21bd157248...: 84 KB unused (39%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://static.rechargecdn.com/assets/js/widget.mi...: 75 KB unused (63%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.googletagmanager.com/gtag/js?id=G-J11M...: 67 KB unused (40%)
Consider code splitting or tree shaking to reduce unused code.
Info::
Total unused JavaScript: 1009 KB
1009 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://7ce243a1e1a2.cdn4.forter.com/sn/7ce243a1e1a2/script.js220 KB92 KB (42%)✓3rd
https://21bd15724800.cdn4.forter.com/sn/21bd15724800/script.js215 KB84 KB (39%)✓3rd
https://21bd15724800.cdn4.forter.com/sn/21bd15724800/script.js215 KB84 KB (39%)✓3rd
https://static.rechargecdn.com/assets/js/widget.min.js?shop=glossier-admin.myshopify.com119 KB75 KB (63%)✓3rd
https://www.googletagmanager.com/gtag/js?id=G-J11MBLGD5V&cx=c&gtm=4e6461169 KB67 KB (40%)✓3rd
https://static.clairedefermat.com/pixel/v2/pixel.js70 KB58 KB (84%)✓3rd
https://www.glossier.com/cdn/shop/t/1393/assets/app.min.js?v=11649421712287302310177488101384 KB55 KB (66%)✓3rd
https://analytics.tiktok.com/i18n/pixel/static/main.MWE0ZWQ3ZWQwMw.js110 KB54 KB (49%)✓3rd
https://www.googletagmanager.com/gtm.js?id=GTM-KW9HP9Z173 KB53 KB (30%)✓3rd
https://www.googletagmanager.com/gtag/js?id=AW-960173363&cx=c&gtm=4e6461144 KB52 KB (36%)✓3rd

Consider code splitting or tree shaking to reduce unused code.

Why this matters

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.

Why this matters

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.

Why this matters

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.

Why this matters

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.

Why this matters

This bundle has high unused code — code-split or tree-shake to ship only what executes.

Source: web.dev / Lighthouse coverage

D
HTTP Caching
Action
no-store (uncacheable)
FIX
no-store (uncacheable)
Info::
Cache-Control: no-store prevents all caching
Intentional for dynamic content, but increases server load for every page view.
Got: private, no-store
Info::
No ETag or Last-Modified header
Conditional requests (304 Not Modified) are not possible without validators.
Cache-Control

private, no-store

DirectiveValueMeaning
private—Only browser cache, not CDN/proxy
no-store—Never cache this response
C
Image Optimization
Action
21 images, 0 KB saveable
REVIEW
21 images, 0 KB saveable
Warning::
https://glossier-prod.imgix.net/files/glossier-soi... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://glossier-prod.imgix.net/files/glossier-soi... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://www.glossier.com/cdn/shop/t/1393/assets/se... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://glossier-prod.imgix.net/files/glossier-soi... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://glossier-prod.imgix.net/files/glossier-soi... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
21 images 646 KB
0 oversized -0 KB
10 legacy format
6 missing dimensions CLS risk

Set explicit width and height to prevent CLS.

Why this matters

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.

Why this matters

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.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Set explicit width and height to prevent CLS.

Why this matters

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.

Why this matters

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.

Why this matters

Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.

Source: web.dev / Core Web Vitals

A+
Text Compression
All text resources are compressed
PASS
All text resources are compressed
Info::
All text resources are compressed
All text resources are properly compressed.
A+
Font Loading
10 fonts (167 KB)
PASS
10 fonts (167 KB)
Info::
10 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

10

167 KB total

Render-blocking

0

of 10

Dominant font-display

swap

Most common across fonts

Font loading timeline
Transfer FOIT (block) FOUT (swap)
0 ms 500 ms 1.0 s 1.5 s FCP 1.3 s LCP 1.7 shttps://www.glossier.com/cdn/shop/t/1393/assets/Apercu.woff?v=27749520405110232131774881013Apercu.woff https://www.glossier.com/cdn/shop/t/1393/assets/Apercu.woff?v=27749520405110232131774881013 — 16.7 KiB — 0 ms — font-display: swaphttps://www.glossier.com/cdn/shop/t/1393/assets/Apercu-Medium.woff?v=135256279722417433531774881013Apercu-Medium.woff https://www.glossier.com/cdn/shop/t/1393/assets/Apercu-Medium.woff?v=135256279722417433531774881013 — 16.8 KiB — 0 ms — font-display: swaphttps://www.glossier.com/cdn/shop/t/1393/assets/Apercu-Mono.woff?v=95926578357820724491774881013Apercu-Mono.woff https://www.glossier.com/cdn/shop/t/1393/assets/Apercu-Mono.woff?v=95926578357820724491774881013 — 11.8 KiB — 0 ms — font-display: swaphttps://www.glossier.com/cdn/shop/t/1393/assets/Apercu-MediumItalic.woff?v=166049247236756587401774881013Apercu-MediumItalic.woff https://www.glossier.com/cdn/shop/t/1393/assets/Apercu-MediumItalic.woff?v=166049247236756587401774881013 — 18.0 KiB — 0 ms — font-display: swaphttps://www.glossier.com/cdn/shop/t/1393/assets/Apercu-Bold.woff?v=77441056927343755651774881013Apercu-Bold.woff https://www.glossier.com/cdn/shop/t/1393/assets/Apercu-Bold.woff?v=77441056927343755651774881013 — 16.5 KiB — 0 ms — font-display: swaphttps://www.glossier.com/cdn/shop/t/1393/assets/Apercu-Italic.woff?v=167501330633256636311774881013Apercu-Italic.woff https://www.glossier.com/cdn/shop/t/1393/assets/Apercu-Italic.woff?v=167501330633256636311774881013 — 18.4 KiB — 0 ms — font-display: swaphttps://cdn.shopify.com/s/files/1/0627/9164/7477/files/font-apercupro-regular.woff2?v=1652966868font-apercupro-regular.... https://cdn.shopify.com/s/files/1/0627/9164/7477/files/font-apercupro-regular.woff2?v=1652966868 — 17.2 KiB — 0 ms — font-display: swaphttps://cdn.shopify.com/s/files/1/0627/9164/7477/files/font-apercupro-medium.woff2?v=1679586878font-apercupro-medium.w... https://cdn.shopify.com/s/files/1/0627/9164/7477/files/font-apercupro-medium.woff2?v=1679586878 — 18.3 KiB — 0 ms — font-display: swaphttps://cdn.shopify.com/s/files/1/0627/9164/7477/files/Apercu.woff2?v=1721062709Apercu.woff2 https://cdn.shopify.com/s/files/1/0627/9164/7477/files/Apercu.woff2?v=1721062709 — 16.7 KiB — 0 ms — font-display: swaphttps://cdn.shopify.com/s/files/1/0627/9164/7477/files/Apercu-Bold.woff2?v=1721062709Apercu-Bold.woff2 https://cdn.shopify.com/s/files/1/0627/9164/7477/files/Apercu-Bold.woff2?v=1721062709 — 16.4 KiB — 0 ms — font-display: swap
Apercu.woff woff swap
Size 17 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
  • Convert to woff2 for ~30% smaller file size
Apercu-Medium.woff woff swap
Size 17 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
  • Convert to woff2 for ~30% smaller file size
Apercu-Mono.woff woff swap
Size 12 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
  • Convert to woff2 for ~30% smaller file size
Apercu-MediumItalic.woff woff swap
Size 18 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
  • Convert to woff2 for ~30% smaller file size
Apercu-Bold.woff woff swap
Size 17 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
  • Convert to woff2 for ~30% smaller file size
Apercu-Italic.woff woff swap
Size 18 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
  • Convert to woff2 for ~30% smaller file size
font-apercupro-regular.... woff2 swap
Size 17 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
font-apercupro-medium.w... woff2 swap
Size 18 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
Apercu.woff2 woff2 swap
Size 17 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
Apercu-Bold.woff2 woff2 swap
Size 16 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
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 ~29 KB and ~58 ms

A+
Resource Caching
All resources properly cached
PASS
All resources properly cached
Info::
No caching issues found
All static resources have appropriate caching headers.
A+
Critical Rendering Path
No render-blocking resources
PASS
No render-blocking resources
Info::
No render-blocking resources detected
A+
Resource Hints
No optimization needed
PASS
No optimization needed
Info::
No resource hint issues
A+
Green Hosting
Whether the site is served from green-energy infrastructure
PASS

Green Hosting

This site is hosted on green energy infrastructure

Provider: Cloudflare

Network Waterfall
350 requests over 0ms
INFO

Performance analysis not available for this result.

Third-Party Script Cost
Per-script blocking time, transfer cost, and cache headers
INFO
100% of JavaScript execution is third-party
First-party Third-party 3359ms · 1660KB · €18/mo
Unattributable
Other
Costly
Execution 553ms
Transfer 0 KB
Monthly Cost €3/mo
www.glossier.com
Other
Costly
Execution 472ms
Transfer 57 KB
Monthly Cost €2/mo
www.glossier.com
Other
Costly
Execution 447ms
Transfer 61 KB
Unused 41%
Monthly Cost €2/mo
edge.fullstory.com
Other
Costly
Execution 308ms
Transfer 80 KB
Unused 33%
Monthly Cost €2/mo
www.glossier.com
Other
Costly
Execution 246ms
Transfer 84 KB
Unused 66%
Monthly Cost €1/mo
Optimizely
A/B Testing
Costly
Execution 234ms
Transfer 105 KB
Unused 31%
Monthly Cost €1/mo
21bd15724800.cdn4.forter.com
Other
Optional
Execution 190ms
Transfer 215 KB
Unused 39%
Monthly Cost €1/mo
onsite.joinground.com
Other
Optional
Execution 164ms
Transfer 68 KB
Monthly Cost €1/mo
Google Tag Manager
Tag Manager
Optional
Execution 137ms
Transfer 173 KB
Unused 30%
Monthly Cost €1/mo
7ce243a1e1a2.cdn4.forter.com
Other
Optional
Execution 108ms
Transfer 220 KB
Unused 42%
Monthly Cost €1/mo
(program):2
Other
Optional
Execution 97ms
Transfer 0 KB
Monthly Cost €1/mo
static.klaviyo.com
Other
Optional
Execution 93ms
Transfer 23 KB
Monthly Cost €0/mo
Google Tag Manager
Tag Manager
Optional
Execution 73ms
Transfer 169 KB
Unused 40%
Monthly Cost €0/mo
analytics.tiktok.com
Other
Optional
Execution 66ms
Transfer 110 KB
Unused 49%
Monthly Cost €0/mo
Google Tag Manager
Tag Manager
Optional
Execution 64ms
Transfer 144 KB
Unused 36%
Monthly Cost €0/mo
www.glossier.com
Other
Optional
Execution 56ms
Transfer 85 KB
Unused 57%
Monthly Cost €0/mo
us-assets.i.posthog.com
Other
Optional
Execution 50ms
Transfer 65 KB
Unused 51%
Monthly Cost €0/mo

These scripts may cost more than they're worth

  • Unattributable adds 553ms and costs ~€3/month
  • www.glossier.com adds 472ms and costs ~€2/month
  • www.glossier.com adds 447ms and costs ~€2/month
  • edge.fullstory.com adds 308ms and costs ~€2/month
  • www.glossier.com adds 246ms and costs ~€1/month
  • Optimizely adds 234ms and costs ~€1/month

100% of JavaScript execution time is spent on third-party scripts. Consider auditing which scripts are essential.

Why this matters

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 553ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.

Why this matters

This script has high main-thread execution time — optimize hot paths or defer.

Source: web.dev

www.glossier.com takes 472ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.

Why this matters

This script has high main-thread execution time — optimize hot paths or defer.

Source: web.dev

www.glossier.com takes 447ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.

Why this matters

This script has high main-thread execution time — optimize hot paths or defer.

Source: web.dev

edge.fullstory.com takes 308ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.

Why this matters

This script has high main-thread execution time — optimize hot paths or defer.

Source: web.dev

www.glossier.com takes 246ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.

Why this matters

This script has high main-thread execution time — optimize hot paths or defer.

Source: web.dev

66% of www.glossier.com's code is unused. The script may be loading features you don't use.

Why this matters

Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.

Source: web.dev

Optimizely takes 234ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.

Why this matters

This script has high main-thread execution time — optimize hot paths or defer.

Source: web.dev

57% of www.glossier.com's code is unused. The script may be loading features you don't use.

Why this matters

Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.

Source: web.dev

51% of us-assets.i.posthog.com's code is unused. The script may be loading features you don't use.

Why this matters

Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.

Source: web.dev

How third-party costs are calculated

All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.

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