Skip to content
https://sncf.com

Performance

· 17 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
77
GRADE
C
FIX
5
REVIEW
2
PASS
8
INFO
2

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

Mobile Desktop
50
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
100
Accessibility Measures how accessible the page is for users with disabilities. Checks color contrast, ARIA labels, and semantic HTML.
96
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.

4.07 s

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

11.59 s

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

507 ms

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

0.001

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

5.29 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.

11.61 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
17
8 PASS 2 REVIEW 5 FIX
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 (1.5 MiB of 1.5 MiB)
Info::
Third-party blocking time is low (0 ms)
100%
First-party Third-party
D
JS Execution Cost
Action
2464ms total JS execution
FIX
2464ms total JS execution
Warning::
https://www.groupe-sncf.com/_next/static/chunks/12...: 834ms CPU time
Warning::
Unattributable: 282ms CPU time
Info::
https://js-datadome.groupe-sncf.com/tags.js: 246ms CPU time
Info::
https://www.groupe-sncf.com/_next/static/chunks/57...: 229ms CPU time
Info::
https://www.groupe-sncf.com/fr: 204ms CPU time
Warning::
Third-party scripts: 2464ms (100% of total)

Main Thread Breakdown

Script Evaluation 64% Script Parsing & Compilation 12% Other 12% Style & Layout 6% Parse HTML & CSS 4%
ScriptTotalScriptingParse/CompileParty
https://www.groupe-sncf.com/_next/static/chunks/1255-31341e05e682b6b5.js834ms729ms13ms3rd
Unattributable282ms29ms0ms3rd
https://js-datadome.groupe-sncf.com/tags.js246ms221ms8ms3rd
https://www.groupe-sncf.com/_next/static/chunks/5771-57f01415e13d0e00.js229ms211ms17ms3rd
https://www.groupe-sncf.com/fr204ms14ms20ms3rd
https://www.googletagmanager.com/gtm.js?id=GTM-PW6KXC5Z&gtm_auth=&gtm_preview=&gtm_cookies_win=x143ms112ms29ms3rd
https://sdk.privacy-center.org/sdk/22ecd6bfac93de604efec0b75b2c796ee1675f92/modern/ui-web-en-web.22ecd6bfac93de604efec0b75b2c796ee1675f92.js133ms70ms18ms3rd
https://www.groupe-sncf.com/_next/static/chunks/9784-a369336b6b66a333.js132ms126ms5ms3rd
https://sdk.privacy-center.org/sdk/22ecd6bfac93de604efec0b75b2c796ee1675f92/modern/sdk.22ecd6bfac93de604efec0b75b2c796ee1675f92.js129ms100ms29ms3rd
https://www.groupe-sncf.com/_next/static/chunks/05f6971a-3deaa127f637de56.js81ms1ms77ms3rd

Showing top 10 of 11 scripts

F
JS Bundles
Action
33 scripts, 524 KB unused
FIX
33 scripts, 524 KB unused
Warning::
https://www.groupe-sncf.com/_next/static/chunks/05...: 215 KB unused (84%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.groupe-sncf.com/_next/static/chunks/14...: 76 KB unused (79%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.googletagmanager.com/gtm.js?id=GTM-PW6...: 67 KB unused (54%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://sdk.privacy-center.org/sdk/22ecd6bfac93de6...: 54 KB unused (53%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.groupe-sncf.com/_next/static/chunks/57...: 47 KB unused (82%)
Consider code splitting or tree shaking to reduce unused code.
Info::
Total unused JavaScript: 524 KB
524 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://www.groupe-sncf.com/_next/static/chunks/05f6971a-3deaa127f637de56.js258 KB215 KB (84%)✓3rd
https://www.groupe-sncf.com/_next/static/chunks/1416-4620eb662f313595.js102 KB76 KB (79%)✓3rd
https://www.googletagmanager.com/gtm.js?id=GTM-PW6KXC5Z&gtm_auth=&gtm_preview=&gtm_cookies_win=x123 KB67 KB (54%)✓3rd
https://sdk.privacy-center.org/sdk/22ecd6bfac93de604efec0b75b2c796ee1675f92/modern/sdk.22ecd6bfac93de604efec0b75b2c796ee1675f92.js102 KB54 KB (53%)✓3rd
https://www.groupe-sncf.com/_next/static/chunks/5771-57f01415e13d0e00.js59 KB47 KB (82%)✓3rd
https://www.groupe-sncf.com/_next/static/chunks/4103-fc17f1c6d23f042f.js43 KB38 KB (91%)✓3rd
https://www.groupe-sncf.com/_next/static/chunks/534-a136d96d74e6a22a.js47 KB26 KB (58%)✓3rd
https://www.groupe-sncf.com/_next/static/chunks/1788-15deef2409962a1c.js7 KB—✓3rd
https://www.groupe-sncf.com/_next/static/chunks/4bd1b696-182b6b13bdad92e3.js55 KB—✓3rd
https://www.groupe-sncf.com/_next/static/chunks/app/error-d73583db1882fd29.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

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
Page Weight Inventory
Action
59 resources · 1.5 MB · 524 KB savings available
FIX
59 resources · 1.5 MB · 524 KB savings available
Warning::
Page weight 533 KB over 1MB target
Got: 1.5 MB Expected: ≤ 1 MB
Info::
~524 KB of savings available
Warning::
58 third-party resources (100% of weight)
Info::
1 resources over 200KB
59 resources · 1.5 MiB · 58 third-party 533.4 KiB over 1MB target
JavaScript 75% · 1.1 MiB
Image 17% · 271.6 KiB
Font 4% · 55.1 KiB
CSS 3% · 42.4 KiB
Document 2% · 25.8 KiB
Other 0% · 976 B

~523.5 KiB of savings available

Remove unused JavaScript: 523.5 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
Page Weight Budget
1.5 MB transferred, 59 requests
REVIEW
1.5 MB transferred, 59 requests
Info::
Page weighs 4.6 MB (1.5 MB transferred)
Warning::
JavaScript is 1.1 MB — consider code splitting or lazy loading
Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.
Got: 1.1 MB
Info::
59 HTTP requests
Info::
Estimated 0.32 g CO2 per page load
1.5 MB / 2.4 MB budget
1.5 MB transferred
59 requests
0.32 g CO2 per page load
JavaScript 1.1 MiB 75%
Images 268.9 KiB 17%
Fonts 55.1 KiB 4%
CSS 42.4 KiB 3%
HTML 23.6 KiB 2%
Other 4.9 KiB 0%
Other 645 B 0%
Other 331 B 0%
0 2.4 MB 4.9 MB
Approaching limit

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

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
Image Optimization
8 images, 0 KB saveable
PASS
8 images, 0 KB saveable
Warning::
https://www.cybermalveillance.gouv.fr/medias/2021/... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
8 images 269 KB
0 oversized -0 KB
1 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

A+
Font Loading
4 fonts (55 KB)
PASS
4 fonts (55 KB)
Info::
4 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

4

55 KB total

Render-blocking

0

of 4

Dominant font-display

swap

Most common across fonts

Font loading timeline
Transfer FOIT (block) FOUT (swap)
0 ms 2.0 s 4.0 s 6.0 s 8.0 s 10.0 s 12.0 s FCP 4.1 s LCP 11.6 shttps://www.groupe-sncf.com/_next/static/media/922d67442fa2d113-s.p.woff2922d67442fa2d113-s.p.woff2 https://www.groupe-sncf.com/_next/static/media/922d67442fa2d113-s.p.woff2 — 17.8 KiB — 95 ms — font-display: swaphttps://www.groupe-sncf.com/_next/static/media/cb7985bf38fb6153-s.p.woff2cb7985bf38fb6153-s.p.woff2 https://www.groupe-sncf.com/_next/static/media/cb7985bf38fb6153-s.p.woff2 — 17.9 KiB — 106 ms — font-display: swaphttps://www.groupe-sncf.com/_next/static/media/e73a90aae6c03fa5-s.p.woff2e73a90aae6c03fa5-s.p.woff2 https://www.groupe-sncf.com/_next/static/media/e73a90aae6c03fa5-s.p.woff2 — 13.5 KiB — 108 ms — font-display: swaphttps://www.groupe-sncf.com/_next/static/media/29b0bf990024f1c7-s.woff229b0bf990024f1c7-s.woff2 https://www.groupe-sncf.com/_next/static/media/29b0bf990024f1c7-s.woff2 — 6.0 KiB — 46 ms — font-display: swap
922d67442fa2d113-s.p.woff2 woff2 swap
Size 18 KB
Load time 95 ms
Start 373 ms
Risk FOUT — text flashes from fallback to web font
cb7985bf38fb6153-s.p.woff2 woff2 swap
Size 18 KB
Load time 106 ms
Start 374 ms
Risk FOUT — text flashes from fallback to web font
e73a90aae6c03fa5-s.p.woff2 woff2 swap
Size 13 KB
Load time 108 ms
Start 374 ms
Risk FOUT — text flashes from fallback to web font
29b0bf990024f1c7-s.woff2 woff2 swap
Size 6 KB
Load time 46 ms
Start 493 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
A+
Render-Blocking Resources
No render-blocking resources detected
PASS
No render-blocking resources detected
Info::
No render-blocking resources detected in <head>
A+
Third-Party Resources
No third-party resources detected
PASS
No third-party resources detected
Network Waterfall
59 requests over 1626ms
INFO
0 ms 2.0 s 4.0 s 6.0 s 8.0 s 10.0 s 12.0 s FCP 4.1 s LCP 11.6 shttps://sncf.com// https://sncf.com/ — 301 — 83 B — 75 ms — h2https://www.sncf.com/www.sncf.com/ https://www.sncf.com/ — 301 — 88 B — 62 ms — h2https://www.groupe-sncf.com/www.groupe-sncf.com/ https://www.groupe-sncf.com/ — 308 — 2.0 KiB — 156 ms — h2https://www.groupe-sncf.com/frwww.groupe-sncf.com/fr https://www.groupe-sncf.com/fr — 200 — 23.6 KiB — 67 ms — h2https://www.groupe-sncf.com/_next/static/media/922d67442fa2d113-s.p.woff2www.groupe-sncf.com/_next/static/me... https://www.groupe-sncf.com/_next/static/media/922d67442fa2d113-s.p.woff2 — 200 — 17.8 KiB — 95 ms — h3https://www.groupe-sncf.com/_next/static/media/cb7985bf38fb6153-s.p.woff2www.groupe-sncf.com/_next/static/me... https://www.groupe-sncf.com/_next/static/media/cb7985bf38fb6153-s.p.woff2 — 200 — 17.9 KiB — 106 ms — h3https://www.groupe-sncf.com/_next/static/media/e73a90aae6c03fa5-s.p.woff2www.groupe-sncf.com/_next/static/me... https://www.groupe-sncf.com/_next/static/media/e73a90aae6c03fa5-s.p.woff2 — 200 — 13.5 KiB — 108 ms — h3https://www.groupe-sncf.com/_next/static/css/77ef6fe080e86852.csswww.groupe-sncf.com/_next/static/cs... https://www.groupe-sncf.com/_next/static/css/77ef6fe080e86852.css — 200 — 19.3 KiB — 78 ms — h3https://www.groupe-sncf.com/_next/static/css/4169b9dceefac52c.csswww.groupe-sncf.com/_next/static/cs... https://www.groupe-sncf.com/_next/static/css/4169b9dceefac52c.css — 200 — 1.9 KiB — 76 ms — h3https://www.groupe-sncf.com/_next/static/css/d808df294caa8a5c.csswww.groupe-sncf.com/_next/static/cs... https://www.groupe-sncf.com/_next/static/css/d808df294caa8a5c.css — 200 — 1.9 KiB — 76 ms — h3https://www.groupe-sncf.com/_next/static/css/358e91d545ff2e24.csswww.groupe-sncf.com/_next/static/cs... https://www.groupe-sncf.com/_next/static/css/358e91d545ff2e24.css — 200 — 1.9 KiB — 56 ms — h3https://www.groupe-sncf.com/_next/static/css/6c1db005254b50e3.csswww.groupe-sncf.com/_next/static/cs... https://www.groupe-sncf.com/_next/static/css/6c1db005254b50e3.css — 200 — 4.0 KiB — 58 ms — h3https://www.groupe-sncf.com/_next/static/css/227a91527b8abe71.csswww.groupe-sncf.com/_next/static/cs... https://www.groupe-sncf.com/_next/static/css/227a91527b8abe71.css — 200 — 11.6 KiB — 89 ms — h3https://www.groupe-sncf.com/_next/static/css/b5802bc2880869ca.csswww.groupe-sncf.com/_next/static/cs... https://www.groupe-sncf.com/_next/static/css/b5802bc2880869ca.css — 200 — 1.8 KiB — 57 ms — h3https://js-datadome.groupe-sncf.com/tags.jsjs-datadome.groupe-sncf.com/tags.js https://js-datadome.groupe-sncf.com/tags.js — 200 — 40.8 KiB — 195 ms — h2https://www.groupe-sncf.com/scripts/critical-min.jswww.groupe-sncf.com/scripts/critica... https://www.groupe-sncf.com/scripts/critical-min.js — 200 — 1.9 KiB — 59 ms — h3https://www.groupe-sncf.com/_next/static/chunks/webpack-48f911772e71b9e7.jswww.groupe-sncf.com/_next/static/ch... https://www.groupe-sncf.com/_next/static/chunks/webpack-48f911772e71b9e7.js — 200 — 3.5 KiB — 49 ms — h3https://www.groupe-sncf.com/_next/static/chunks/4bd1b696-182b6b13bdad92e3.jswww.groupe-sncf.com/_next/static/ch... https://www.groupe-sncf.com/_next/static/chunks/4bd1b696-182b6b13bdad92e3.js — 200 — 54.9 KiB — 69 ms — h3https://www.groupe-sncf.com/_next/static/chunks/1255-31341e05e682b6b5.jswww.groupe-sncf.com/_next/static/ch... https://www.groupe-sncf.com/_next/static/chunks/1255-31341e05e682b6b5.js — 200 — 45.4 KiB — 81 ms — h3https://www.groupe-sncf.com/_next/static/chunks/main-app-ef3a8679441a467c.jswww.groupe-sncf.com/_next/static/ch... https://www.groupe-sncf.com/_next/static/chunks/main-app-ef3a8679441a467c.js — 200 — 1.8 KiB — 54 ms — h3https://www.groupe-sncf.com/_next/static/chunks/4909-5daf217e5b4ca788.jswww.groupe-sncf.com/_next/static/ch... https://www.groupe-sncf.com/_next/static/chunks/4909-5daf217e5b4ca788.js — 200 — 9.9 KiB — 65 ms — h3https://www.groupe-sncf.com/_next/static/chunks/5239-927756e38ffca55f.jswww.groupe-sncf.com/_next/static/ch... https://www.groupe-sncf.com/_next/static/chunks/5239-927756e38ffca55f.js — 200 — 7.1 KiB — 55 ms — h3https://www.groupe-sncf.com/_next/static/chunks/1788-15deef2409962a1c.jswww.groupe-sncf.com/_next/static/ch... https://www.groupe-sncf.com/_next/static/chunks/1788-15deef2409962a1c.js — 200 — 7.0 KiB — 48 ms — h3https://www.groupe-sncf.com/_next/static/chunks/app/error-d73583db1882fd29.jswww.groupe-sncf.com/_next/static/ch... https://www.groupe-sncf.com/_next/static/chunks/app/error-d73583db1882fd29.js — 200 — 2.0 KiB — 42 ms — h3https://www.groupe-sncf.com/_next/static/chunks/app/global-error-23cde0a43e615922.jswww.groupe-sncf.com/_next/static/ch... https://www.groupe-sncf.com/_next/static/chunks/app/global-error-23cde0a43e615922.js — 200 — 1.9 KiB — 54 ms — h3https://www.groupe-sncf.com/_next/static/chunks/05f6971a-3deaa127f637de56.jswww.groupe-sncf.com/_next/static/ch... https://www.groupe-sncf.com/_next/static/chunks/05f6971a-3deaa127f637de56.js — 200 — 258.4 KiB — 100 ms — h3https://www.groupe-sncf.com/_next/static/chunks/65fb8c99-2286602842fcc7e3.jswww.groupe-sncf.com/_next/static/ch... https://www.groupe-sncf.com/_next/static/chunks/65fb8c99-2286602842fcc7e3.js — 200 — 23.6 KiB — 54 ms — h3https://www.groupe-sncf.com/_next/static/chunks/865-2051a693686a9757.jswww.groupe-sncf.com/_next/static/ch... https://www.groupe-sncf.com/_next/static/chunks/865-2051a693686a9757.js — 200 — 31.4 KiB — 104 ms — h3https://www.groupe-sncf.com/_next/static/chunks/4103-fc17f1c6d23f042f.jswww.groupe-sncf.com/_next/static/ch... https://www.groupe-sncf.com/_next/static/chunks/4103-fc17f1c6d23f042f.js — 200 — 43.2 KiB — 109 ms — h3https://www.groupe-sncf.com/_next/static/chunks/534-a136d96d74e6a22a.jswww.groupe-sncf.com/_next/static/ch... https://www.groupe-sncf.com/_next/static/chunks/534-a136d96d74e6a22a.js — 200 — 47.3 KiB — 109 ms — h3
0 ms 2.0 s 4.0 s 6.0 s 8.0 s 10.0 s 12.0 s FCP 4.1 s LCP 11.6 shttps://sncf.com// https://sncf.com/ — 301 — 83 B — 75 ms — h2https://www.sncf.com/www.sncf.com/ https://www.sncf.com/ — 301 — 88 B — 62 ms — h2https://www.groupe-sncf.com/www.groupe-sncf.com/ https://www.groupe-sncf.com/ — 308 — 2.0 KiB — 156 ms — h2https://www.groupe-sncf.com/frwww.groupe-sncf.com/fr https://www.groupe-sncf.com/fr — 200 — 23.6 KiB — 67 ms — h2https://www.groupe-sncf.com/_next/static/media/922d67442fa2d113-s.p.woff2www.groupe-sncf.com/_next/static/me... https://www.groupe-sncf.com/_next/static/media/922d67442fa2d113-s.p.woff2 — 200 — 17.8 KiB — 95 ms — h3https://www.groupe-sncf.com/_next/static/media/cb7985bf38fb6153-s.p.woff2www.groupe-sncf.com/_next/static/me... https://www.groupe-sncf.com/_next/static/media/cb7985bf38fb6153-s.p.woff2 — 200 — 17.9 KiB — 106 ms — h3https://www.groupe-sncf.com/_next/static/media/e73a90aae6c03fa5-s.p.woff2www.groupe-sncf.com/_next/static/me... https://www.groupe-sncf.com/_next/static/media/e73a90aae6c03fa5-s.p.woff2 — 200 — 13.5 KiB — 108 ms — h3https://www.groupe-sncf.com/_next/static/css/77ef6fe080e86852.csswww.groupe-sncf.com/_next/static/cs... https://www.groupe-sncf.com/_next/static/css/77ef6fe080e86852.css — 200 — 19.3 KiB — 78 ms — h3https://www.groupe-sncf.com/_next/static/css/4169b9dceefac52c.csswww.groupe-sncf.com/_next/static/cs... https://www.groupe-sncf.com/_next/static/css/4169b9dceefac52c.css — 200 — 1.9 KiB — 76 ms — h3https://www.groupe-sncf.com/_next/static/css/d808df294caa8a5c.csswww.groupe-sncf.com/_next/static/cs... https://www.groupe-sncf.com/_next/static/css/d808df294caa8a5c.css — 200 — 1.9 KiB — 76 ms — h3https://www.groupe-sncf.com/_next/static/css/358e91d545ff2e24.csswww.groupe-sncf.com/_next/static/cs... https://www.groupe-sncf.com/_next/static/css/358e91d545ff2e24.css — 200 — 1.9 KiB — 56 ms — h3https://www.groupe-sncf.com/_next/static/css/6c1db005254b50e3.csswww.groupe-sncf.com/_next/static/cs... https://www.groupe-sncf.com/_next/static/css/6c1db005254b50e3.css — 200 — 4.0 KiB — 58 ms — h3https://www.groupe-sncf.com/_next/static/css/227a91527b8abe71.csswww.groupe-sncf.com/_next/static/cs... https://www.groupe-sncf.com/_next/static/css/227a91527b8abe71.css — 200 — 11.6 KiB — 89 ms — h3https://www.groupe-sncf.com/_next/static/css/b5802bc2880869ca.csswww.groupe-sncf.com/_next/static/cs... https://www.groupe-sncf.com/_next/static/css/b5802bc2880869ca.css — 200 — 1.8 KiB — 57 ms — h3https://js-datadome.groupe-sncf.com/tags.jsjs-datadome.groupe-sncf.com/tags.js https://js-datadome.groupe-sncf.com/tags.js — 200 — 40.8 KiB — 195 ms — h2https://www.groupe-sncf.com/scripts/critical-min.jswww.groupe-sncf.com/scripts/critica... https://www.groupe-sncf.com/scripts/critical-min.js — 200 — 1.9 KiB — 59 ms — h3https://www.groupe-sncf.com/_next/static/chunks/webpack-48f911772e71b9e7.jswww.groupe-sncf.com/_next/static/ch... https://www.groupe-sncf.com/_next/static/chunks/webpack-48f911772e71b9e7.js — 200 — 3.5 KiB — 49 ms — h3https://www.groupe-sncf.com/_next/static/chunks/4bd1b696-182b6b13bdad92e3.jswww.groupe-sncf.com/_next/static/ch... https://www.groupe-sncf.com/_next/static/chunks/4bd1b696-182b6b13bdad92e3.js — 200 — 54.9 KiB — 69 ms — h3https://www.groupe-sncf.com/_next/static/chunks/1255-31341e05e682b6b5.jswww.groupe-sncf.com/_next/static/ch... https://www.groupe-sncf.com/_next/static/chunks/1255-31341e05e682b6b5.js — 200 — 45.4 KiB — 81 ms — h3https://www.groupe-sncf.com/_next/static/chunks/main-app-ef3a8679441a467c.jswww.groupe-sncf.com/_next/static/ch... https://www.groupe-sncf.com/_next/static/chunks/main-app-ef3a8679441a467c.js — 200 — 1.8 KiB — 54 ms — h3https://www.groupe-sncf.com/_next/static/chunks/4909-5daf217e5b4ca788.jswww.groupe-sncf.com/_next/static/ch... https://www.groupe-sncf.com/_next/static/chunks/4909-5daf217e5b4ca788.js — 200 — 9.9 KiB — 65 ms — h3https://www.groupe-sncf.com/_next/static/chunks/5239-927756e38ffca55f.jswww.groupe-sncf.com/_next/static/ch... https://www.groupe-sncf.com/_next/static/chunks/5239-927756e38ffca55f.js — 200 — 7.1 KiB — 55 ms — h3https://www.groupe-sncf.com/_next/static/chunks/1788-15deef2409962a1c.jswww.groupe-sncf.com/_next/static/ch... https://www.groupe-sncf.com/_next/static/chunks/1788-15deef2409962a1c.js — 200 — 7.0 KiB — 48 ms — h3https://www.groupe-sncf.com/_next/static/chunks/app/error-d73583db1882fd29.jswww.groupe-sncf.com/_next/static/ch... https://www.groupe-sncf.com/_next/static/chunks/app/error-d73583db1882fd29.js — 200 — 2.0 KiB — 42 ms — h3https://www.groupe-sncf.com/_next/static/chunks/app/global-error-23cde0a43e615922.jswww.groupe-sncf.com/_next/static/ch... https://www.groupe-sncf.com/_next/static/chunks/app/global-error-23cde0a43e615922.js — 200 — 1.9 KiB — 54 ms — h3https://www.groupe-sncf.com/_next/static/chunks/05f6971a-3deaa127f637de56.jswww.groupe-sncf.com/_next/static/ch... https://www.groupe-sncf.com/_next/static/chunks/05f6971a-3deaa127f637de56.js — 200 — 258.4 KiB — 100 ms — h3https://www.groupe-sncf.com/_next/static/chunks/65fb8c99-2286602842fcc7e3.jswww.groupe-sncf.com/_next/static/ch... https://www.groupe-sncf.com/_next/static/chunks/65fb8c99-2286602842fcc7e3.js — 200 — 23.6 KiB — 54 ms — h3https://www.groupe-sncf.com/_next/static/chunks/865-2051a693686a9757.jswww.groupe-sncf.com/_next/static/ch... https://www.groupe-sncf.com/_next/static/chunks/865-2051a693686a9757.js — 200 — 31.4 KiB — 104 ms — h3https://www.groupe-sncf.com/_next/static/chunks/4103-fc17f1c6d23f042f.jswww.groupe-sncf.com/_next/static/ch... https://www.groupe-sncf.com/_next/static/chunks/4103-fc17f1c6d23f042f.js — 200 — 43.2 KiB — 109 ms — h3https://www.groupe-sncf.com/_next/static/chunks/534-a136d96d74e6a22a.jswww.groupe-sncf.com/_next/static/ch... https://www.groupe-sncf.com/_next/static/chunks/534-a136d96d74e6a22a.js — 200 — 47.3 KiB — 109 ms — h3https://www.groupe-sncf.com/_next/static/chunks/1416-4620eb662f313595.jswww.groupe-sncf.com/_next/static/ch... https://www.groupe-sncf.com/_next/static/chunks/1416-4620eb662f313595.js — 200 — 102.1 KiB — 115 ms — h3https://www.groupe-sncf.com/_next/static/chunks/9745-884de31fbc68d4fe.jswww.groupe-sncf.com/_next/static/ch... https://www.groupe-sncf.com/_next/static/chunks/9745-884de31fbc68d4fe.js — 200 — 9.3 KiB — 116 ms — h3https://www.groupe-sncf.com/_next/static/chunks/6713-e652fc0cba95fe44.jswww.groupe-sncf.com/_next/static/ch... https://www.groupe-sncf.com/_next/static/chunks/6713-e652fc0cba95fe44.js — 200 — 6.2 KiB — 113 ms — h3https://www.groupe-sncf.com/_next/static/chunks/3037-bfe4d96258a7a206.jswww.groupe-sncf.com/_next/static/ch... https://www.groupe-sncf.com/_next/static/chunks/3037-bfe4d96258a7a206.js — 200 — 6.4 KiB — 116 ms — h3https://www.groupe-sncf.com/_next/static/chunks/5771-57f01415e13d0e00.jswww.groupe-sncf.com/_next/static/ch... https://www.groupe-sncf.com/_next/static/chunks/5771-57f01415e13d0e00.js — 200 — 58.6 KiB — 134 ms — h3https://www.groupe-sncf.com/_next/static/chunks/app/%5Blang%5D/%5B...slug%5D/page-da1f2079a7b035fb.jswww.groupe-sncf.com/_next/static/ch... https://www.groupe-sncf.com/_next/static/chunks/app/%5Blang%5D/%5B...slug%5D/page-da1f2079a7b035fb.js — 200 — 3.3 KiB — 119 ms — h3https://www.groupe-sncf.com/_next/static/chunks/9784-a369336b6b66a333.jswww.groupe-sncf.com/_next/static/ch... https://www.groupe-sncf.com/_next/static/chunks/9784-a369336b6b66a333.js — 200 — 30.7 KiB — 131 ms — h3https://www.groupe-sncf.com/_next/static/chunks/3951-fac6c1995d9c03ba.jswww.groupe-sncf.com/_next/static/ch... https://www.groupe-sncf.com/_next/static/chunks/3951-fac6c1995d9c03ba.js — 200 — 18.7 KiB — 125 ms — h3https://www.groupe-sncf.com/_next/static/chunks/app/%5Blang%5D/layout-423275be34a75ea0.jswww.groupe-sncf.com/_next/static/ch... https://www.groupe-sncf.com/_next/static/chunks/app/%5Blang%5D/layout-423275be34a75ea0.js — 200 — 1.9 KiB — 128 ms — h3https://www.groupe-sncf.com/_next/static/media/29b0bf990024f1c7-s.woff2www.groupe-sncf.com/_next/static/me... https://www.groupe-sncf.com/_next/static/media/29b0bf990024f1c7-s.woff2 — 200 — 6.0 KiB — 46 ms — h3https://www.groupe-sncf.com/images/logo-light.svgwww.groupe-sncf.com/images/logo-lig... https://www.groupe-sncf.com/images/logo-light.svg — 200 — 3.7 KiB — 91 ms — h3https://www.groupe-sncf.com/medias-publics/styles/crop_1_1/public/2026-04/Zou.png.webp?VersionId=xtZzpAAHmLXNWxE5zjMPx3EGkBuaqa.j&itok=8zI1SZZqwww.groupe-sncf.com/medias-publics/... https://www.groupe-sncf.com/medias-publics/styles/crop_1_1/public/2026-04/Zou.png.webp?VersionId=xtZzpAAHmLXNWxE5zjMPx3EGkBuaqa.j&itok=8zI1SZZq — 200 — 27.6 KiB — 94 ms — h3https://www.groupe-sncf.com/medias-publics/styles/crop_1_1/public/2025-10/Hexafret_Gevrey_Chambertin.jpg.webp?VersionId=WEiR5rItSO2alVrpvXyqldJM2JnUiRcC&h=bfced127&itok=ey42_KQYwww.groupe-sncf.com/medias-publics/... https://www.groupe-sncf.com/medias-publics/styles/crop_1_1/public/2025-10/Hexafret_Gevrey_Chambertin.jpg.webp?VersionId=WEiR5rItSO2alVrpvXyqldJM2JnUiRcC&h=bfced127&itok=ey42_KQY — 200 — 35.8 KiB — 97 ms — h3https://www.groupe-sncf.com/medias-publics/styles/crop_1_1/public/2024-09/tgv-inoui-quai-gare.jpg.webp?VersionId=77avJqDQc1wYrSSYA_DV4xubhji0_Ixj&itok=ytVA8_u8www.groupe-sncf.com/medias-publics/... https://www.groupe-sncf.com/medias-publics/styles/crop_1_1/public/2024-09/tgv-inoui-quai-gare.jpg.webp?VersionId=77avJqDQc1wYrSSYA_DV4xubhji0_Ixj&itok=ytVA8_u8 — 200 — 37.8 KiB — 95 ms — h3https://www.groupe-sncf.com/medias-publics/styles/crop_1_1/public/2024-02/transilien-sebgodefroy160328-sq.jpg.webp?h=4726a6b5&itok=jc11vrYqwww.groupe-sncf.com/medias-publics/... https://www.groupe-sncf.com/medias-publics/styles/crop_1_1/public/2024-02/transilien-sebgodefroy160328-sq.jpg.webp?h=4726a6b5&itok=jc11vrYq — 200 — 60.5 KiB — 96 ms — h3data:image/webp;base64,UklGRh4AAABXRUJQVlA4TBEAAAAvAQAAAAfQ//73v/+BiOh/AAA=data:image/webp;base64,UklGRh4AAABX... data:image/webp;base64,UklGRh4AAABXRUJQVlA4TBEAAAAvAQAAAAfQ//73v/+BiOh/AAA= — 200 — 0 B — 0 ms — datahttps://www.groupe-sncf.com/favicon.icowww.groupe-sncf.com/favicon.ico https://www.groupe-sncf.com/favicon.ico — 200 — 2.8 KiB — 91 ms — h3https://www.googletagmanager.com/gtm.js?id=GTM-PW6KXC5Z&gtm_auth=&gtm_preview=&gtm_cookies_win=xwww.googletagmanager.com/gtm.js?id=... https://www.googletagmanager.com/gtm.js?id=GTM-PW6KXC5Z&gtm_auth=&gtm_preview=&gtm_cookies_win=x — 200 — 123.3 KiB — 181 ms — h2https://sdk.privacy-center.org/c207b5b4-7bfd-47ff-9f46-3522ae638631/loader.js?target_type=notice&target=VCpZWfpXsdk.privacy-center.org/c207b5b4-7bf... https://sdk.privacy-center.org/c207b5b4-7bfd-47ff-9f46-3522ae638631/loader.js?target_type=notice&target=VCpZWfpX — 200 — 35.1 KiB — 246 ms — h2https://www.groupe-sncf.com/_next/static/chunks/3128.5801b8bffcbbe482.jswww.groupe-sncf.com/_next/static/ch... https://www.groupe-sncf.com/_next/static/chunks/3128.5801b8bffcbbe482.js — 200 — 2.6 KiB — 35 ms — h3https://www.groupe-sncf.com/_next/static/chunks/611.ad1e194fa1c99701.jswww.groupe-sncf.com/_next/static/ch... https://www.groupe-sncf.com/_next/static/chunks/611.ad1e194fa1c99701.js — 200 — 1.8 KiB — 33 ms — h3https://sdk.privacy-center.org/sdk/22ecd6bfac93de604efec0b75b2c796ee1675f92/modern/sdk.22ecd6bfac93de604efec0b75b2c796ee1675f92.jssdk.privacy-center.org/sdk/22ecd6bf... https://sdk.privacy-center.org/sdk/22ecd6bfac93de604efec0b75b2c796ee1675f92/modern/sdk.22ecd6bfac93de604efec0b75b2c796ee1675f92.js — 200 — 101.7 KiB — 39 ms — h2https://sdk.privacy-center.org/sdk/22ecd6bfac93de604efec0b75b2c796ee1675f92/modern/ui-web-en-web.22ecd6bfac93de604efec0b75b2c796ee1675f92.jssdk.privacy-center.org/sdk/22ecd6bf... https://sdk.privacy-center.org/sdk/22ecd6bfac93de604efec0b75b2c796ee1675f92/modern/ui-web-en-web.22ecd6bfac93de604efec0b75b2c796ee1675f92.js — 200 — 53.1 KiB — 34 ms — h3https://tag.aticdn.net/piano-analytics.jstag.aticdn.net/piano-analytics.js https://tag.aticdn.net/piano-analytics.js — 200 — 26.6 KiB — 95 ms — h2https://www.cybermalveillance.gouv.fr/medias/2021/01/groupe-sncf.jpgwww.cybermalveillance.gouv.fr/media... https://www.cybermalveillance.gouv.fr/medias/2021/01/groupe-sncf.jpg — 200 — 43.6 KiB — 106 ms — h2https://nssvsmp.pa-cd.com/event?s=642220&idclient=moansqnh3c4w47jwnssvsmp.pa-cd.com/event?s=642220&id... https://nssvsmp.pa-cd.com/event?s=642220&idclient=moansqnh3c4w47jw — 204 — 331 B — 119 ms — h2https://www.groupe-sncf.com/medias-publics/styles/crop_1_1/public/2025-09/Voies-ferres_Bourgogne-OlivierFoulon.jpg.webp?VersionId=FgyBp1pfvS1OFxec__py5acpHqVckZ_w&h=bfced127&itok=-4npIQYtwww.groupe-sncf.com/medias-publics/... https://www.groupe-sncf.com/medias-publics/styles/crop_1_1/public/2025-09/Voies-ferres_Bourgogne-OlivierFoulon.jpg.webp?VersionId=FgyBp1pfvS1OFxec__py5acpHqVckZ_w&h=bfced127&itok=-4npIQYt — 200 — 59.8 KiB — 74 ms — h3blob:https://www.groupe-sncf.com/6d48fc4b-b94c-41b9-bb42-ba5aac97ba43www.groupe-sncf.com/6d48fc4b-b94c-4... blob:https://www.groupe-sncf.com/6d48fc4b-b94c-41b9-bb42-ba5aac97ba43 — 200 — -1 B — 41 ms — blobhttps://js-datadome.groupe-sncf.com/js/js-datadome.groupe-sncf.com/js/ https://js-datadome.groupe-sncf.com/js/ — 200 — 645 B — 66 ms — h2
HTML JavaScript CSS Images Fonts XHR/Fetch Other
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 2464ms · 762KB · $33/mo
www.groupe-sncf.com
Other
Costly
Execution 834ms
Transfer 45 KB
Monthly Cost $11/mo
Unattributable
Other
Costly
Execution 282ms
Transfer 0 KB
Monthly Cost $4/mo
js-datadome.groupe-sncf.com
Other
Costly
Execution 246ms
Transfer 41 KB
Monthly Cost $3/mo
www.groupe-sncf.com
Other
Costly
Execution 229ms
Transfer 59 KB
Unused 82%
Monthly Cost $3/mo
www.groupe-sncf.com
Other
Costly
Execution 204ms
Transfer 24 KB
Monthly Cost $3/mo
Google Tag Manager
Tag Manager
Optional
Execution 143ms
Transfer 123 KB
Unused 54%
Monthly Cost $2/mo
sdk.privacy-center.org
Other
Optional
Execution 133ms
Transfer 53 KB
Monthly Cost $2/mo
www.groupe-sncf.com
Other
Optional
Execution 132ms
Transfer 31 KB
Monthly Cost $2/mo
sdk.privacy-center.org
Other
Optional
Execution 129ms
Transfer 102 KB
Unused 53%
Monthly Cost $2/mo
www.groupe-sncf.com
Other
Optional
Execution 81ms
Transfer 258 KB
Unused 84%
Monthly Cost $1/mo
tag.aticdn.net
Other
Optional
Execution 51ms
Transfer 27 KB
Monthly Cost $1/mo

These scripts may cost more than they're worth

  • www.groupe-sncf.com adds 834ms and costs ~$11/month
  • Unattributable adds 282ms and costs ~$4/month
  • js-datadome.groupe-sncf.com adds 246ms and costs ~$3/month
  • www.groupe-sncf.com adds 229ms and costs ~$3/month
  • www.groupe-sncf.com adds 204ms and costs ~$3/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.groupe-sncf.com takes 834ms 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 282ms 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

js-datadome.groupe-sncf.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

www.groupe-sncf.com takes 229ms 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

82% of www.groupe-sncf.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

www.groupe-sncf.com takes 204ms 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 Google Tag Manager'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

53% of sdk.privacy-center.org'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

84% of www.groupe-sncf.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.

Send Feedback