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Performance

· 14 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
65
GRADE
D
FIX
5
REVIEW
2
PASS
5
INFO
2

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

Mobile Desktop
64
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
98
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.
92
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.

734 ms

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

1.25 s

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

2.44 s

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

0.027

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

1.68 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.

6.98 s

Page Load Progression

1.4 s
2.9 s
4.3 s
5.8 s
7.2 s
8.7 s
10.1 s
11.5 s
Checks
14
5 PASS 2 REVIEW 5 FIX
F
Page Weight Budget
Action
31.9 MB transferred, 268 requests
FIX
31.9 MB transferred, 268 requests
Critical::
Page weighs 46.5 MB (31.9 MB transferred)
Warning::
Images are 3.5 MB — compress or use modern formats
Convert images to WebP/AVIF and resize to display dimensions to reduce transfer size.
Got: 3.5 MB
Warning::
JavaScript is 2.1 MB — consider code splitting or lazy loading
Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.
Got: 2.1 MB
Info::
Fonts are 239 KB — consider subsetting or using system fonts
Subset fonts to include only used characters, or switch to system font stacks.
Got: 239 KB
Info::
CSS is 206 KB — consider purging unused styles
Remove unused CSS rules with tools like PurgeCSS to reduce stylesheet size.
Got: 206 KB
Warning::
268 HTTP requests — consider bundling or reducing
Each request adds latency. Bundle small files, use sprites, or eliminate unnecessary requests.
Info::
Estimated 6.7 g CO2 per page load
31.9 MB / 2.4 MB budget
31.9 MB transferred
268 requests
6.7 g CO2 per page load
Other 25.7 MiB 81%
Images 3.5 MiB 11%
JavaScript 2.1 MiB 7%
Fonts 239.1 KiB 1%
CSS 205.6 KiB 1%
HTML 85.3 KiB 0%
Other 68.3 KiB 0%
Other 19.8 KiB 0%
Other 7.1 KiB 0%
Other 553 B 0%
Other 0 B 0%
0 2.4 MB 4.9 MB
Over budget

Convert images to WebP/AVIF and resize to display dimensions to reduce transfer size.

Why this matters

Image bandwidth is high — modern formats (WebP/AVIF) and resizing typically cut it 50%+.

Source: web.dev

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

Subset fonts to include only used characters, or switch to system font stacks.

Why this matters

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.

Why this matters

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.

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 (31.8 MiB of 31.9 MiB)
Info::
Third-party blocking time is low (0 ms)
100%
First-party Third-party
F
JS Execution Cost
Action
7502ms total JS execution
FIX
7502ms total JS execution
Warning::
https://slack.com/: 4277ms CPU time
Warning::
Unattributable: 1280ms CPU time
Warning::
https://www.googletagmanager.com/gtm.js?id=GTM-KH2...: 677ms CPU time
Warning::
https://www.googletagmanager.com/gtag/js?id=G-QTJQ...: 323ms CPU time
Warning::
https://t.contentsquare.net/uxa/eaf9ce4ae4903.js: 276ms CPU time
Info::
Third-party scripts: 3224ms (43% of total)

Main Thread Breakdown

Other 68% Script Evaluation 23% Script Parsing & Compilation 4%
ScriptTotalScriptingParse/CompileParty
https://slack.com/4277ms12ms2ms1st
Unattributable1280ms59ms0ms3rd
https://www.googletagmanager.com/gtm.js?id=GTM-KH2LPK677ms542ms81ms3rd
https://www.googletagmanager.com/gtag/js?id=G-QTJQME5M5D&cx=c&gtm=4e6420h2323ms277ms24ms3rd
https://t.contentsquare.net/uxa/eaf9ce4ae4903.js276ms192ms81ms3rd
https://a.slack-edge.com/bv1-13-br/rollup-marketing.8312e05a3c017ab833de.marketing.min.js130ms89ms28ms3rd
https://www.googletagmanager.com/gtag/js?id=DC-11463663&cx=c&gtm=4e6420h2128ms95ms31ms3rd
https://www.googletagmanager.com/gtag/destination?id=DC-12632256&cx=c&gtm=4e6420h297ms84ms11ms3rd
https://tag.demandbase.com/n1qTRo0B.min.js90ms52ms2ms3rd
https://b-code.liadm.com/a-01kd.min.js90ms71ms11ms3rd

Showing top 10 of 12 scripts

F
JS Bundles
Action
43 scripts, 604 KB unused
FIX
43 scripts, 604 KB unused
Warning::
https://a.slack-edge.com/bv1-13-br/rollup-marketin...: 136 KB unused (73%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://t.contentsquare.net/uxa/eaf9ce4ae4903.js: 75 KB unused (54%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.googletagmanager.com/gtag/js?id=DC-114...: 59 KB unused (46%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.googletagmanager.com/gtag/destination?...: 59 KB unused (46%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://cdn.cookielaw.org/scripttemplates/202402.1...: 58 KB unused (55%)
Consider code splitting or tree shaking to reduce unused code.
Info::
Total unused JavaScript: 604 KB
604 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://a.slack-edge.com/bv1-13-br/rollup-marketing.8312e05a3c017ab833de.marketing.min.js186 KB136 KB (73%)✓3rd
https://t.contentsquare.net/uxa/eaf9ce4ae4903.js140 KB75 KB (54%)✓3rd
https://www.googletagmanager.com/gtag/js?id=DC-11463663&cx=c&gtm=4e6420h2128 KB59 KB (46%)✓3rd
https://www.googletagmanager.com/gtag/destination?id=DC-12632256&cx=c&gtm=4e6420h2130 KB59 KB (46%)✓3rd
https://cdn.cookielaw.org/scripttemplates/202402.1.0/otBannerSdk.js105 KB58 KB (55%)✓3rd
https://www.googletagmanager.com/gtm.js?id=GTM-KH2LPK196 KB58 KB (29%)✓3rd
https://www.googletagmanager.com/gtag/js?id=G-QTJQME5M5D&cx=c&gtm=4e6420h2178 KB51 KB (29%)✓3rd
https://a.slack-edge.com/bv1-13-br/swiper.c790778cd9fb4f6b41e1.marketing.min.js35 KB35 KB (100%)✓3rd
https://a.slack-edge.com/bv1-13-br/marketing-core.cf1dd39ec9100fc5cc4f.marketing.min.js31 KB28 KB (91%)✓3rd
https://a.slack-edge.com/bv1-13-br/marketing-customer-videos.c547a581ff0c64e6cfa8.marketing.min.js25 KB24 KB (99%)✓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

F
HTTP Caching
Action
No cache headers
FIX
No cache headers
Warning::
No Cache-Control header found
Browsers will use heuristic caching, which can be unpredictable. Set explicit cache headers.

No Cache-Control header

Adding a Cache-Control header can significantly improve repeat-visit performance.

C
Image Optimization
Action
79 images, 0 KB saveable
REVIEW
79 images, 0 KB saveable
Warning::
https://slack.com/marketing/img/homepage/revamped-... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://slack.com/marketing/img/homepage/revamped-... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://a.slack-edge.com/fd21de4/marketing/img/nav... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://a.slack-edge.com/38f0e7c/marketing/img/nav... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://a.slack-edge.com/7d8fca7/marketing/img/nav... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://slack.com/marketing/img/homepage/revamped-... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://a.slack-edge.com/38f0e7c/marketing/img/nav... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://a.slack-edge.com/fd21de4/marketing/img/nav... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://slack.com/marketing/img/homepage/revamped-... 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://slack.com/marketing/img/homepage/revamped-... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://a.slack-edge.com/b518216/marketing/img/nav... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
79 images 1.1 MB
0 oversized -0 KB
58 legacy format
12 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

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

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

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

C
Green Hosting
Action
Whether the site is served from green-energy infrastructure
REVIEW

Green Hosting

No green hosting detected

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
7 fonts (239 KB)
PASS
7 fonts (239 KB)
Info::
7 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

7

239 KB total

Render-blocking

0

of 7

Dominant font-display

swap

Most common across fonts

Font loading timeline
Transfer FOIT (block) FOUT (swap)
0 ms 500 ms 1.0 s FCP 734 ms LCP 1.2 shttps://a.slack-edge.com/bv1-13-br/salesforce-sans-bold-edf948a2181aa81e6045.woff2salesforce-sans-bold-ed... https://a.slack-edge.com/bv1-13-br/salesforce-sans-bold-edf948a2181aa81e6045.woff2 — 27.5 KiB — 0 ms — font-display: swaphttps://a.slack-edge.com/bv1-13-br/salesforce-sans-regular-679547df303acfaf9b97.woff2salesforce-sans-regular... https://a.slack-edge.com/bv1-13-br/salesforce-sans-regular-679547df303acfaf9b97.woff2 — 27.5 KiB — 0 ms — font-display: swaphttps://a.slack-edge.com/bv1-13-br/salesforce-sans-semi-bold-f3873250b116e522a23d.woff2salesforce-sans-semi-bo... https://a.slack-edge.com/bv1-13-br/salesforce-sans-semi-bold-f3873250b116e522a23d.woff2 — 27.5 KiB — 0 ms — font-display: swaphttps://a.slack-edge.com/bv1-13-br/avant-garde-8402dfbd4149ce947d8b.woff2avant-garde-8402dfbd414... https://a.slack-edge.com/bv1-13-br/avant-garde-8402dfbd4149ce947d8b.woff2 — 66.9 KiB — 0 ms — font-display: swaphttps://a.slack-edge.com/bv1-13-br/salesforce-sans-light-italic-4033c989dfb65fb9645e.woff2salesforce-sans-light-i... https://a.slack-edge.com/bv1-13-br/salesforce-sans-light-italic-4033c989dfb65fb9645e.woff2 — 28.3 KiB — 0 ms — font-display: swaphttps://a.slack-edge.com/bv1-13-br/salesforce-sans-book-e71e6c0595be7a07330a.woff2salesforce-sans-book-e7... https://a.slack-edge.com/bv1-13-br/salesforce-sans-book-e71e6c0595be7a07330a.woff2 — 27.7 KiB — 0 ms — font-display: swaphttps://fonts.gstatic.com/s/roboto/v48/KFO7CnqEu92Fr1ME7kSn66aGLdTylUAMa3yUBHMdazQ.woff2KFO7CnqEu92Fr1ME7kSn66a... https://fonts.gstatic.com/s/roboto/v48/KFO7CnqEu92Fr1ME7kSn66aGLdTylUAMa3yUBHMdazQ.woff2 — 33.9 KiB — 0 ms — font-display: swap
salesforce-sans-bold-ed... woff2 swap
Size 27 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
salesforce-sans-regular... woff2 swap
Size 27 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
salesforce-sans-semi-bo... woff2 swap
Size 27 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
avant-garde-8402dfbd414... woff2 swap
Size 67 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
salesforce-sans-light-i... woff2 swap
Size 28 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
salesforce-sans-book-e7... woff2 swap
Size 28 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
KFO7CnqEu92Fr1ME7kSn66a... woff2 swap
Size 34 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)
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
Network Waterfall
268 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
43% of JavaScript execution is third-party
First-party Third-party 3224ms · 1143KB · $60/mo
Unattributable
Other
Costly
Execution 1280ms
Transfer 0 KB
Monthly Cost $24/mo
Google Tag Manager
Tag Manager
Costly
Execution 677ms
Transfer 196 KB
Unused 29%
Monthly Cost $13/mo
Google Tag Manager
Tag Manager
Costly
Execution 323ms
Transfer 178 KB
Unused 29%
Monthly Cost $6/mo
t.contentsquare.net
Other
Costly
Execution 276ms
Transfer 140 KB
Unused 54%
Monthly Cost $5/mo
a.slack-edge.com
Other
Optional
Execution 130ms
Transfer 186 KB
Unused 73%
Monthly Cost $2/mo
Google Tag Manager
Tag Manager
Optional
Execution 128ms
Transfer 128 KB
Unused 46%
Monthly Cost $2/mo
Google Tag Manager
Tag Manager
Optional
Execution 97ms
Transfer 130 KB
Unused 46%
Monthly Cost $2/mo
tag.demandbase.com
Other
Optional
Execution 90ms
Transfer 19 KB
Monthly Cost $2/mo
b-code.liadm.com
Other
Optional
Execution 90ms
Transfer 47 KB
Monthly Cost $2/mo
OneTrust
Consent
Essential
Execution 76ms
Transfer 105 KB
Unused 55%
Monthly Cost $1/mo
www.mczbf.com
Other
Optional
Execution 58ms
Transfer 13 KB
Monthly Cost $1/mo

These scripts may cost more than they're worth

  • Unattributable adds 1280ms and costs ~$24/month
  • Google Tag Manager adds 677ms and costs ~$13/month
  • Google Tag Manager adds 323ms and costs ~$6/month
  • t.contentsquare.net adds 276ms and costs ~$5/month

43% of JavaScript execution time comes from third-party scripts.

Why this matters

Third-party scripts (analytics, ads, social, A/B testing) often dominate execution time — every one is a perf-and-privacy tax.

Learn more ▾

Each third-party script is a black box: you don't control when it loads, what it executes, or how much it grows. They often account for a major share of total blocking time on average sites (HTTP Archive's Web Almanac documents the trend). Audit which ones you actually need, defer the rest, and use facade patterns (lite-youtube, lite-vimeo) for embedded media.

Source: web.dev / HTTP Archive Web Almanac

Unattributable takes 1280ms 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

Google Tag Manager takes 677ms 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

Google Tag Manager takes 323ms 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

t.contentsquare.net takes 276ms 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

54% of t.contentsquare.net'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

73% of a.slack-edge.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

55% of OneTrust'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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