Performance
· 15 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.Performance-focused optimization plan with CWV assessment, top offenders, and time estimates
First Contentful Paint First Contentful Paint — how long until the browser renders the first piece of content. Under 1.8s is good.
1.36 s
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
1.43 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
46 ms
Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.
0.004
Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.
2.50 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.
2.73 s
Page Load Progression
DThird-Party ImpactAction100% third-party, 0 ms blockingFIX
DJS BundlesAction75 scripts, 306 KB unusedFIX
Downloaded but never executed on this page.
| Script | Size | Unused | Minified | Party |
|---|---|---|---|---|
| https://cdns.eu1.gigya.com/js/gigya.js?apikey=3_kWKuPgcdAybqnqxq_MvHVk0-6PN8Zk8pIIkJM_yXOu-qLPDDsGOtIDFfpGivtbeO | 238 KB | 136 KB (57%) | ✓ | 3rd |
| https://static-oaos.rtbf.be/14034624651/_next/static/chunks/5580-d9c0223d3a2e4389.js | 64 KB | 55 KB (86%) | ✓ | 3rd |
| https://connect.facebook.net/en_US/bundle/sdk.js/ | 78 KB | 49 KB (63%) | ✓ | 3rd |
| https://sdk.privacy-center.org/sdk/22ecd6bfac93de604efec0b75b2c796ee1675f92/modern/sdk.22ecd6bfac93de604efec0b75b2c796ee1675f92.js | 102 KB | 45 KB (44%) | ✓ | 3rd |
| https://static-oaos.rtbf.be/14034624651/_next/static/chunks/8982-2de817e62cbcab4a.js | 23 KB | 20 KB (88%) | ✓ | 3rd |
| https://static-oaos.rtbf.be/14034624651/_next/static/chunks/8544-4b2ef8d343b522fb.js | 24 KB | — | ✓ | 3rd |
| https://static-oaos.rtbf.be/14034624651/_next/static/chunks/8994-c59f29b7252055af.js | 5 KB | — | ✓ | 3rd |
| https://static-oaos.rtbf.be/14034624651/_next/static/chunks/webpack-ce9baa13865cfb6d.js | 5 KB | — | ✓ | 3rd |
| https://static-oaos.rtbf.be/14034624651/_next/static/chunks/87c73c54-dd8d81ac9604067c.js | 53 KB | — | ✓ | 3rd |
| https://static-oaos.rtbf.be/14034624651/_next/static/chunks/18-2db3bc3db671e157.js | 45 KB | — | ✓ | 3rd |
Consider code splitting or tree shaking to reduce unused code.
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.
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.
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.
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.
This bundle has high unused code — code-split or tree-shake to ship only what executes.
Source: web.dev / Lighthouse coverage
DPage Weight InventoryAction121 resources · 1.5 MB · 306 KB savings availableFIX
~305.7 KiB of savings available
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 121 resources | 1.5 MiB | ||||||
FHTTP CachingActionNo cache headersFIX
No Cache-Control header
Adding a Cache-Control header can significantly improve repeat-visit performance.
BPage Weight Budget1.5 MB transferred, 121 requestsREVIEW
Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.
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.
High HTTP request count — bundling, sprite-ing, and HTTP/2 server push can reduce per-request overhead.
Source: web.dev
BImage Optimization29 images, 0 KB saveableREVIEW
CJS Execution CostAction1642ms total JS executionREVIEW
Main Thread Breakdown
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| https://www.rtbf.be/ | 643ms | 69ms | 64ms | 3rd |
| Unattributable | 281ms | 52ms | 0ms | 3rd |
| https://static-oaos.rtbf.be/14034624651/_next/static/chunks/18-2db3bc3db671e157.js | 225ms | 182ms | 4ms | 3rd |
| https://sdk.privacy-center.org/sdk/22ecd6bfac93de604efec0b75b2c796ee1675f92/modern/ui-web-fr-web.22ecd6bfac93de604efec0b75b2c796ee1675f92.js | 129ms | 37ms | 19ms | 3rd |
| https://sdk.privacy-center.org/sdk/22ecd6bfac93de604efec0b75b2c796ee1675f92/modern/sdk.22ecd6bfac93de604efec0b75b2c796ee1675f92.js | 112ms | 85ms | 14ms | 3rd |
| https://static-oaos.rtbf.be/js/lazysizes/lazysizes.min.js | 104ms | 63ms | 0ms | 3rd |
| https://cdns.eu1.gigya.com/js/gigya.js?apikey=3_kWKuPgcdAybqnqxq_MvHVk0-6PN8Zk8pIIkJM_yXOu-qLPDDsGOtIDFfpGivtbeO | 96ms | 75ms | 16ms | 3rd |
| https://static-oaos.rtbf.be/14034624651/_next/static/chunks/8173-9be690f4029cd385.js | 53ms | 47ms | 3ms | 3rd |
CGreen HostingActionWhether the site is served from green-energy infrastructureREVIEW
Green Hosting
No green hosting detected
A+Text CompressionAll text resources are compressedPASS
A+Font Loading1 fonts (30 KB)PASS
Web fonts
1
30 KB total
Render-blocking
0
of 1
Dominant font-display
swap
Most common across fonts
Font loading timeline
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 CachingAll resources properly cachedPASS
A+Critical Rendering PathNo render-blocking resourcesPASS
A+Resource HintsNo optimization neededPASS
Network Waterfall121 requests over 4577msINFO
Third-Party Script CostPer-script blocking time, transfer cost, and cache headersINFO
| Script | Category | Execution | Transfer | Unused | Monthly Cost | Verdict |
|---|---|---|---|---|---|---|
www.rtbf.be www.rtbf.be | Other | 643ms | 148 KB | — | €7/mo | Costly |
Unattributable Unattributable | Other | 281ms | 0 KB | — | €3/mo | Costly |
static-oaos.rtbf.be static-oaos.rtbf.be | Other | 225ms | 45 KB | — | €2/mo | Costly |
sdk.privacy-center.org sdk.privacy-center.org | Other | 129ms | 56 KB | — | €1/mo | Optional |
sdk.privacy-center.org sdk.privacy-center.org | Other | 112ms | 102 KB | 44% | €1/mo | Optional |
static-oaos.rtbf.be static-oaos.rtbf.be | Other | 104ms | 4 KB | — | €1/mo | Optional |
cdns.eu1.gigya.com cdns.eu1.gigya.com | Other | 96ms | 238 KB | 57% | €1/mo | Optional |
static-oaos.rtbf.be static-oaos.rtbf.be | Other | 53ms | 17 KB | — | €1/mo | Optional |
These scripts may cost more than they're worth
- www.rtbf.be adds 643ms and costs ~€7/month
- Unattributable adds 281ms and costs ~€3/month
- static-oaos.rtbf.be adds 225ms and costs ~€2/month
100% of JavaScript execution time is spent on third-party scripts. Consider auditing which scripts are essential.
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.rtbf.be takes 643ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
Unattributable takes 281ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
static-oaos.rtbf.be takes 225ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
57% of cdns.eu1.gigya.com's code is unused. The script may be loading features you don't use.
Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.
Source: web.dev