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https://www.colissimo.fr

Performance

· 14 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
73
GRADE
C
FIX
4
REVIEW
3
PASS
5
INFO
2

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

Mobile Desktop
61
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
76
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.
83
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.

2.46 s

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

4.35 s

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

132 ms

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

0.032

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

2.60 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.

4.35 s

Page Load Progression

375 ms
750 ms
1.1 s
1.5 s
1.9 s
2.2 s
2.6 s
3.0 s
Checks
14
5 PASS 3 REVIEW 4 FIX
F
Page Weight Budget
Action
6.0 MB transferred, 331 requests
FIX
6.0 MB transferred, 331 requests
Critical::
Page weighs 22.4 MB (6.0 MB transferred)
Warning::
Images are 1.5 MB — compress or use modern formats
Convert images to WebP/AVIF and resize to display dimensions to reduce transfer size.
Got: 1.5 MB
Info::
CSS is 1.1 MB — consider purging unused styles
Remove unused CSS rules with tools like PurgeCSS to reduce stylesheet size.
Got: 1.1 MB
Warning::
JavaScript is 1.0 MB — consider code splitting or lazy loading
Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.
Got: 1.0 MB
Warning::
331 HTTP requests — consider bundling or reducing
Each request adds latency. Bundle small files, use sprites, or eliminate unnecessary requests.
Info::
Estimated 1.3 g CO2 per page load
6.0 MB / 2.4 MB budget
6.0 MB transferred
331 requests
1.3 g CO2 per page load
Other 2.1 MiB 35%
Images 1.5 MiB 25%
CSS 1.1 MiB 19%
JavaScript 1.0 MiB 17%
Fonts 166.8 KiB 3%
HTML 63.2 KiB 1%
Other 18.3 KiB 0%
Other 10.3 KiB 0%
Other 858 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

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

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 (6.0 MiB of 6.0 MiB)
Info::
Third-party blocking time is low (0 ms)
100%
First-party Third-party
D
JS Bundles
Action
89 scripts, 401 KB unused
FIX
89 scripts, 401 KB unused
Warning::
https://www.laposte.fr/ecom/_nuxt/C6m16DWd.js: 286 KB unused (57%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://cdn.tagcommander.com/1491/tc_LaboutiqueLaP...: 46 KB unused (58%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://try.abtasty.com/5714a31785e8fb2356ca3d1bd2...: 40 KB unused (39%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.laposte.fr/ruxitagentjs_ICA7NVfhqrux_1...: 29 KB unused (36%)
Consider code splitting or tree shaking to reduce unused code.
Info::
Total unused JavaScript: 401 KB
401 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://www.laposte.fr/ecom/_nuxt/C6m16DWd.js508 KB286 KB (57%)✓3rd
https://cdn.tagcommander.com/1491/tc_LaboutiqueLaPoste_21.js80 KB46 KB (58%)✓3rd
https://try.abtasty.com/5714a31785e8fb2356ca3d1bd25e4a43/main.1e0116ad91cee0a97856.js105 KB40 KB (39%)✓3rd
https://www.laposte.fr/ruxitagentjs_ICA7NVfhqrux_10333260303165926.js82 KB29 KB (36%)✓3rd
https://www.laposte.fr/ecom/_nuxt/CnNrbjCf.js4 KB—✓3rd
https://www.laposte.fr/ecom/_nuxt/BdKfpypI.js1 KB—✓3rd
https://www.laposte.fr/ecom/_nuxt/DJZIH3mZ.js1 KB—✓3rd
https://www.laposte.fr/ecom/_nuxt/BPVQLFSw.js0 KB—✓3rd
https://www.laposte.fr/ecom/_nuxt/ZZSzK1uO.js2 KB—✓3rd
https://www.laposte.fr/ecom/_nuxt/B-F2C3zi.js2 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

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.

B
Image Optimization
47 images, 0 KB saveable
REVIEW
47 images, 0 KB saveable
Warning::
https://www.laposte.fr/ecom/occ/smartedit/medias/s... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
47 images 1.5 MB
0 oversized -0 KB
17 legacy format
1 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

C
JS Execution Cost
Action
1805ms total JS execution
REVIEW
1805ms total JS execution
Warning::
https://www.laposte.fr/ruxitagentjs_ICA7NVfhqrux_1...: 639ms CPU time
Warning::
Unattributable: 439ms CPU time
Warning::
https://www.laposte.fr/colissimo: 369ms CPU time
Info::
https://www.laposte.fr/ecom/_nuxt/entry.C0t7vErM.c...: 179ms CPU time
Info::
https://cdn.tagcommander.com/1491/tc_LaboutiqueLaP...: 64ms CPU time
Warning::
Third-party scripts: 1805ms (100% of total)

Main Thread Breakdown

Script Evaluation 44% Other 25% Style & Layout 15% Parse HTML & CSS 9%
ScriptTotalScriptingParse/CompileParty
https://www.laposte.fr/ruxitagentjs_ICA7NVfhqrux_10333260303165926.js639ms606ms5ms3rd
Unattributable439ms125ms0ms3rd
https://www.laposte.fr/colissimo369ms3ms1ms3rd
https://www.laposte.fr/ecom/_nuxt/entry.C0t7vErM.css179ms0ms0ms3rd
https://cdn.tagcommander.com/1491/tc_LaboutiqueLaPoste_21.js64ms39ms12ms3rd
https://try.abtasty.com/5714a31785e8fb2356ca3d1bd25e4a43/main.1e0116ad91cee0a97856.js59ms46ms10ms3rd
https://www.laposte.fr/ecom/_nuxt/C6aQWrs0.js56ms21ms0ms3rd
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 (167 KB)
PASS
7 fonts (167 KB)
Info::
7 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

7

167 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 1.0 s 2.0 s 3.0 s 4.0 s FCP 2.5 s LCP 4.3 shttps://www.laposte.fr/ecom/_nuxt/Montserrat-Bold.DKC_CUCq.woff2Montserrat-Bold.DKC_CUC... https://www.laposte.fr/ecom/_nuxt/Montserrat-Bold.DKC_CUCq.woff2 — 25.9 KiB — 0 ms — font-display: swaphttps://www.laposte.fr/ecom/_nuxt/laposte-regular.Czc1z7iL.woff2laposte-regular.Czc1z7i... https://www.laposte.fr/ecom/_nuxt/laposte-regular.Czc1z7iL.woff2 — 28.8 KiB — 0 ms — font-display: swaphttps://www.laposte.fr/ecom/_nuxt/Roboto-Medium.CF9-ZKNh.woff2Roboto-Medium.CF9-ZKNh.... https://www.laposte.fr/ecom/_nuxt/Roboto-Medium.CF9-ZKNh.woff2 — 19.1 KiB — 0 ms — font-display: swaphttps://www.laposte.fr/ecom/_nuxt/laposte-light.C-AUD0cx.woff2laposte-light.C-AUD0cx.... https://www.laposte.fr/ecom/_nuxt/laposte-light.C-AUD0cx.woff2 — 29.9 KiB — 0 ms — font-display: swaphttps://www.laposte.fr/ecom/_nuxt/Roboto-Regular.BJU_f3hk.woff2Roboto-Regular.BJU_f3hk... https://www.laposte.fr/ecom/_nuxt/Roboto-Regular.BJU_f3hk.woff2 — 19.2 KiB — 0 ms — font-display: swaphttps://www.laposte.fr/ecom/_nuxt/Montserrat-Semi-Bold.CuXOa3e0.woff2Montserrat-Semi-Bold.Cu... https://www.laposte.fr/ecom/_nuxt/Montserrat-Semi-Bold.CuXOa3e0.woff2 — 25.2 KiB — 0 ms — font-display: swaphttps://www.laposte.fr/ecom/_nuxt/Roboto-Bold.C-ZlbZ-v.woff2Roboto-Bold.C-ZlbZ-v.woff2 https://www.laposte.fr/ecom/_nuxt/Roboto-Bold.C-ZlbZ-v.woff2 — 18.7 KiB — 0 ms — font-display: swap
Montserrat-Bold.DKC_CUC... woff2 swap
Size 26 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
laposte-regular.Czc1z7i... woff2 swap
Size 29 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
Roboto-Medium.CF9-ZKNh.... woff2 swap
Size 19 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
laposte-light.C-AUD0cx.... woff2 swap
Size 30 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
Roboto-Regular.BJU_f3hk... woff2 swap
Size 19 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
Montserrat-Semi-Bold.Cu... woff2 swap
Size 25 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
Roboto-Bold.C-ZlbZ-v.woff2 woff2 swap
Size 19 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
331 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 1805ms · 1053KB · €20/mo
www.laposte.fr
Other
Costly
Execution 639ms
Transfer 82 KB
Unused 36%
Monthly Cost €7/mo
Unattributable
Other
Costly
Execution 439ms
Transfer 0 KB
Monthly Cost €5/mo
www.laposte.fr
Other
Costly
Execution 369ms
Transfer 63 KB
Monthly Cost €4/mo
www.laposte.fr
Other
Optional
Execution 179ms
Transfer 722 KB
Monthly Cost €2/mo
cdn.tagcommander.com
Other
Optional
Execution 64ms
Transfer 80 KB
Unused 58%
Monthly Cost €1/mo
try.abtasty.com
Other
Optional
Execution 59ms
Transfer 105 KB
Unused 39%
Monthly Cost €1/mo
www.laposte.fr
Other
Optional
Execution 56ms
Transfer 0 KB
Monthly Cost €1/mo

These scripts may cost more than they're worth

  • www.laposte.fr adds 639ms and costs ~€7/month
  • Unattributable adds 439ms and costs ~€5/month
  • www.laposte.fr adds 369ms and costs ~€4/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

www.laposte.fr takes 639ms 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

Unattributable takes 439ms 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.laposte.fr takes 369ms 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

58% of cdn.tagcommander.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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