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Performance

· 15 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
85
GRADE
B
FIX
4
REVIEW
4
PASS
5
INFO
2

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

Mobile Desktop
95
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
93
Accessibility Measures how accessible the page is for users with disabilities. Checks color contrast, ARIA labels, and semantic HTML.
100
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.

1.11 s

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

1.15 s

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

10 ms

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

0.002

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

1.11 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.

1.26 s

Page Load Progression

411 ms
821 ms
1.2 s
1.6 s
2.1 s
2.5 s
2.9 s
3.3 s
Checks
15
5 PASS 4 REVIEW 4 FIX
F
Page Weight Budget
Action
4.3 MB transferred, 14 requests
FIX
4.3 MB transferred, 14 requests
Critical::
Page weighs 4.8 MB (4.3 MB transferred)
Info::
14 HTTP requests
Info::
Estimated 0.90 g CO2 per page load
4.3 MB / 2.4 MB budget
4.3 MB transferred
14 requests
0.90 g CO2 per page load
Other 4.0 MiB 93%
JavaScript 161.4 KiB 4%
Images 59.7 KiB 1%
Fonts 47.3 KiB 1%
HTML 31.8 KiB 1%
Other 15.2 KiB 0%
CSS 1.2 KiB 0%
Other 578 B 0%
Other 545 B 0%
0 2.4 MB 4.9 MB
Over budget
D
Third-Party Impact
Action
99% third-party, 0 ms blocking
FIX
99% third-party, 0 ms blocking
Warning::
Third-party code accounts for 99% of page weight (4.3 MiB of 4.3 MiB)
Info::
Third-party blocking time is low (0 ms)
99%
First-party Third-party
D
Page Weight Inventory
Action
14 resources · 4.3 MB · 64 KB savings available
FIX
14 resources · 4.3 MB · 64 KB savings available
Warning::
Page weight 3.3 MB over 1MB target
Got: 4.3 MB Expected: ≤ 1 MB
Info::
~64 KB of savings available
Warning::
11 third-party resources (99% of weight)
Info::
1 resources over 200KB
14 resources · 4.3 MiB · 11 third-party 3.3 MiB over 1MB target
Media 93% · 4.0 MiB
JavaScript 4% · 161.4 KiB
Image 2% · 74.9 KiB
Font 1% · 47.3 KiB
Document 1% · 31.8 KiB
CSS 0% · 1.2 KiB
Other 0% · 1.1 KiB

~63.8 KiB of savings available

Remove unused JavaScript: 63.8 KiB
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.

B
Image Optimization
4 images, 0 KB saveable
REVIEW
4 images, 0 KB saveable
Warning::
https://assets-v2.slid.es/assets/icons/ai-icon-whi... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://assets-v2.slid.es/assets/logos/openai-lock... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
4 images 60 KB
0 oversized -0 KB
3 legacy format
2 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

C
JS Execution Cost
Action
1094ms total JS execution
REVIEW
1094ms total JS execution
Warning::
https://assets-v2.slid.es/assets/marketing-c53fa6b...: 520ms CPU time
Warning::
https://slides.com/: 331ms CPU time
Info::
https://www.googletagmanager.com/gtag/js?id=G-LWVD...: 132ms CPU time
Info::
Unattributable: 110ms CPU time
Warning::
Third-party scripts: 763ms (70% of total)

Main Thread Breakdown

Other 57% Style & Layout 20% Script Evaluation 14% Rendering 4%
ScriptTotalScriptingParse/CompileParty
https://assets-v2.slid.es/assets/marketing-c53fa6b3c542fa59a39ad05d7e6c6e152f7fab4824e400e9a89e04955a2ee90f.js520ms37ms3ms3rd
https://slides.com/331ms4ms1ms1st
https://www.googletagmanager.com/gtag/js?id=G-LWVDH9STBJ132ms105ms22ms3rd
Unattributable110ms4ms0ms3rd
B
JS Bundles
2 scripts, 64 KB unused
REVIEW
2 scripts, 64 KB unused
Warning::
https://www.googletagmanager.com/gtag/js?id=G-LWVD...: 64 KB unused (42%)
Consider code splitting or tree shaking to reduce unused code.
Info::
Total unused JavaScript: 64 KB
64 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://www.googletagmanager.com/gtag/js?id=G-LWVDH9STBJ152 KB64 KB (42%)✓3rd
https://assets-v2.slid.es/assets/marketing-c53fa6b3c542fa59a39ad05d7e6c6e152f7fab4824e400e9a89e04955a2ee90f.js10 KB—✓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

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
1 fonts (47 KB)
PASS
1 fonts (47 KB)
Info::
1 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

1

47 KB total

Render-blocking

0

of 1

Dominant font-display

swap

Most common across fonts

Font loading timeline
Transfer FOIT (block) FOUT (swap)
0 ms 500 ms 1.0 s FCP 1.1 s LCP 1.1 shttps://fonts.gstatic.com/s/inter/v20/UcC73FwrK3iLTeHuS_nVMrMxCp50SjIa1ZL7W0Q5nw.woff2UcC73FwrK3iLTeHuS_nVMrM... https://fonts.gstatic.com/s/inter/v20/UcC73FwrK3iLTeHuS_nVMrMxCp50SjIa1ZL7W0Q5nw.woff2 — 47.3 KiB — 7 ms — font-display: swap
UcC73FwrK3iLTeHuS_nVMrM... woff2 swap
Size 47 KB
Load time 7 ms
Start 567 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
14 requests over 1280ms
INFO
0 ms 500 ms 1.0 s FCP 1.1 s LCP 1.1 shttps://slides.com// https://slides.com/ — 200 — 31.8 KiB — 393 ms — h2https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600&display=swapfonts.googleapis.com/css2?family=In... https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600&display=swap — 200 — 1.2 KiB — 28 ms — h2https://www.googletagmanager.com/gtag/js?id=G-LWVDH9STBJwww.googletagmanager.com/gtag/js?id... https://www.googletagmanager.com/gtag/js?id=G-LWVDH9STBJ — 200 — 151.8 KiB — 47 ms — h2https://static.slid.es/site/homepage/v3/avatars-4.pngstatic.slid.es/site/homepage/v3/ava... https://static.slid.es/site/homepage/v3/avatars-4.png — 200 — 56.9 KiB — 322 ms — http/1.1https://assets-v2.slid.es/assets/icons/ai-icon-white-06e5a57a3e8a4681ad2075c0a1a1aafddbd04fdd303a3f17e67f21a2b4c33313.svgassets-v2.slid.es/assets/icons/ai-i... https://assets-v2.slid.es/assets/icons/ai-icon-white-06e5a57a3e8a4681ad2075c0a1a1aafddbd04fdd303a3f17e67f21a2b4c33313.svg — 200 — 1.2 KiB — 304 ms — h2https://assets-v2.slid.es/assets/logos/openai-lockup-5a28b637ffcde9e25fcac5790b7ac24fbaa3fd591f955062ec2c6021618e400a.svgassets-v2.slid.es/assets/logos/open... https://assets-v2.slid.es/assets/logos/openai-lockup-5a28b637ffcde9e25fcac5790b7ac24fbaa3fd591f955062ec2c6021618e400a.svg — 200 — 1.7 KiB — 305 ms — h2https://slides.com/manifest.json/manifest.json https://slides.com/manifest.json — 200 — 578 B — 288 ms — h2https://assets-v2.slid.es/assets/marketing-c53fa6b3c542fa59a39ad05d7e6c6e152f7fab4824e400e9a89e04955a2ee90f.jsassets-v2.slid.es/assets/marketing-... https://assets-v2.slid.es/assets/marketing-c53fa6b3c542fa59a39ad05d7e6c6e152f7fab4824e400e9a89e04955a2ee90f.js — 200 — 9.7 KiB — 306 ms — h2data:image/svg+xml;base64,PD94bWwgdmVyc2lvbj0iMS4wIiBlbmNvZGluZz0idXRmLTgiPz4NCjwhLS0gR2VuZXJhdG9yO…data:image/svg+xml;base64,PD94bWwgd... data:image/svg+xml;base64,PD94bWwgdmVyc2lvbj0iMS4wIiBlbmNvZGluZz0idXRmLTgiPz4NCjwhLS0gR2VuZXJhdG9yO… — 200 — 0 B — 0 ms — datadata:image/svg+xml;base64,PD94bWwgdmVyc2lvbj0iMS4wIiBlbmNvZGluZz0idXRmLTgiPz4NCjwhLS0gR2VuZXJhdG9yO…data:image/svg+xml;base64,PD94bWwgd... data:image/svg+xml;base64,PD94bWwgdmVyc2lvbj0iMS4wIiBlbmNvZGluZz0idXRmLTgiPz4NCjwhLS0gR2VuZXJhdG9yO… — 200 — 0 B — 0 ms — datahttps://fonts.gstatic.com/s/inter/v20/UcC73FwrK3iLTeHuS_nVMrMxCp50SjIa1ZL7W0Q5nw.woff2fonts.gstatic.com/s/inter/v20/UcC73... https://fonts.gstatic.com/s/inter/v20/UcC73FwrK3iLTeHuS_nVMrMxCp50SjIa1ZL7W0Q5nw.woff2 — 200 — 47.3 KiB — 7 ms — h3https://region1.google-analytics.com/g/collect?v=2&tid=G-LWVDH9STBJ&gtm=45je64k0v886234903za200zd886234903&_p=1776888958212&gcd=13l3l3l2l1l1&npa=1&dma_cps=a&dma=1&are=1&cid=1388247692.1776888959&frm=0&pscdl=noapi&rcb=1&sr=800x600&uaa=x86&uab=64&uafvl=Not-A.Brand%3B24.0.0.0%7CChromium%3B146.0.7680.164&uam=&uamb=0&uap=macOS&uapv=10.15.7&uaw=0&ul=en-us&_s=1&tag_exp=0~115616985~115938465~115938468~117266400~117512543~118128922~118463261&dt=home-index&sid=1776888958&sct=1&seg=0&dl=https%3A%2F%2Fslides.com%2F&en=page_view&_fv=1&_nsi=1&_ss=1&_ee=1&tfd=738region1.google-analytics.com/g/coll... https://region1.google-analytics.com/g/collect?v=2&tid=G-LWVDH9STBJ&gtm=45je64k0v886234903za200zd886234903&_p=1776888958212&gcd=13l3l3l2l1l1&npa=1&dma_cps=a&dma=1&are=1&cid=1388247692.1776888959&frm=0&pscdl=noapi&rcb=1&sr=800x600&uaa=x86&uab=64&uafvl=Not-A.Brand%3B24.0.0.0%7CChromium%3B146.0.7680.164&uam=&uamb=0&uap=macOS&uapv=10.15.7&uaw=0&ul=en-us&_s=1&tag_exp=0~115616985~115938465~115938468~117266400~117512543~118128922~118463261&dt=home-index&sid=1776888958&sct=1&seg=0&dl=https%3A%2F%2Fslides.com%2F&en=page_view&_fv=1&_nsi=1&_ss=1&_ee=1&tfd=738 — 204 — 545 B — 110 ms — h2https://slides.com/favicon.ico/favicon.ico https://slides.com/favicon.ico — 200 — 15.2 KiB — 99 ms — h2https://static.slid.es/site/homepage/v3/homepage-editor-2022-1261x735.mp4static.slid.es/site/homepage/v3/hom... https://static.slid.es/site/homepage/v3/homepage-editor-2022-1261x735.mp4 — 206 — 4.0 MiB — 3 ms — http/1.1
HTML JavaScript CSS Images Fonts XHR/Fetch Other
Third-Party Script Cost
Per-script blocking time, transfer cost, and cache headers
INFO
70% of JavaScript execution is third-party
First-party Third-party 763ms · 161KB · €8/mo
assets-v2.slid.es
Other
Costly
Execution 520ms
Transfer 10 KB
Monthly Cost €6/mo
Google Tag Manager
Tag Manager
Optional
Execution 132ms
Transfer 152 KB
Unused 42%
Monthly Cost €1/mo
Unattributable
Other
Optional
Execution 110ms
Transfer 0 KB
Monthly Cost €1/mo

These scripts may cost more than they're worth

  • assets-v2.slid.es adds 520ms and costs ~€6/month

70% 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

assets-v2.slid.es takes 520ms 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

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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