Performance
· 17 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.
3.16 s
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
20.35 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
1.01 s
Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.
0.000
Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.
8.60 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.
21.72 s
Page Load Progression
FPage Weight BudgetAction4.5 MB transferred, 134 requestsFIX
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
Convert images to WebP/AVIF and resize to display dimensions to reduce transfer size.
Image bandwidth is high — modern formats (WebP/AVIF) and resizing typically cut it 50%+.
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
DThird-Party ImpactAction98% third-party, 0 ms blockingFIX
FJS Execution CostAction4275ms total JS executionFIX
Main Thread Breakdown
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| https://cdn.nos.nl/assets/nosnl/6bf4e31523fce2f86266c6f0560b31ac952c9171/_next/static/chunks/framework-9ab5fe1e97350b85.js | 882ms | 785ms | 23ms | 3rd |
| Unattributable | 790ms | 18ms | 0ms | 3rd |
| https://cdn.nos.nl/assets/nosnl/6bf4e31523fce2f86266c6f0560b31ac952c9171/_next/static/chunks/pages/index-b3b4f1f12f566054.js | 675ms | 628ms | 4ms | 3rd |
| https://nos.nl/ | 616ms | 46ms | 2ms | 1st |
| https://cdn.nos.nl/assets/nosnl/6bf4e31523fce2f86266c6f0560b31ac952c9171/_next/static/chunks/main-8114cb73924c51cd.js | 435ms | 305ms | 25ms | 3rd |
| https://cdn.nos.nl/assets/nosnl/6bf4e31523fce2f86266c6f0560b31ac952c9171/_next/static/chunks/7376-d7a5a10d7b447ee3.js | 384ms | 363ms | 19ms | 3rd |
| https://cdn.nos.nl/assets/nosnl/6bf4e31523fce2f86266c6f0560b31ac952c9171/_next/static/chunks/pages/_app-8f250bde26208f54.js | 261ms | 196ms | 62ms | 3rd |
| https://cdn.nos.nl/assets/nosnl/6bf4e31523fce2f86266c6f0560b31ac952c9171/_next/static/chunks/pages/zoeken-db9043167c580620.js | 68ms | 62ms | 6ms | 3rd |
| https://cdn.nos.nl/assets/nosnl/6bf4e31523fce2f86266c6f0560b31ac952c9171/_next/static/chunks/pages/live-26cf66b0921bbf86.js | 57ms | 41ms | 16ms | 3rd |
| https://cdn.nos.nl/assets/nosnl/6bf4e31523fce2f86266c6f0560b31ac952c9171/_next/static/chunks/bf32f307-9ede5c4e981eede4.js | 56ms | 1ms | 55ms | 3rd |
Showing top 10 of 11 scripts
FJS BundlesAction74 scripts, 2.2 MB unusedFIX
Downloaded but never executed on this page.
| Script | Size | Unused | Minified | Party |
|---|---|---|---|---|
| https://cdn.nos.nl/assets/nosnl/6bf4e31523fce2f86266c6f0560b31ac952c9171/_next/static/chunks/bf32f307-9ede5c4e981eede4.js | 471 KB | 420 KB (89%) | ✓ | 3rd |
| https://cdn.nos.nl/assets/nosnl/6bf4e31523fce2f86266c6f0560b31ac952c9171/_next/static/chunks/pages/_app-8f250bde26208f54.js | 499 KB | 265 KB (53%) | ✓ | 3rd |
| https://cdn.nos.nl/assets/nosnl/6bf4e31523fce2f86266c6f0560b31ac952c9171/_next/static/chunks/main-8114cb73924c51cd.js | 215 KB | 97 KB (45%) | ✓ | 3rd |
| https://cdn.nos.nl/assets/nosnl/6bf4e31523fce2f86266c6f0560b31ac952c9171/_next/static/chunks/7376-d7a5a10d7b447ee3.js | 176 KB | 95 KB (58%) | ✓ | 3rd |
| https://cdn.nos.nl/assets/nosnl/6bf4e31523fce2f86266c6f0560b31ac952c9171/_next/static/chunks/7376-d7a5a10d7b447ee3.js | 0 KB | 95 KB (58%) | ✓ | 3rd |
| https://cdn.nos.nl/assets/nosnl/6bf4e31523fce2f86266c6f0560b31ac952c9171/_next/static/chunks/9935-51de23a318d826f7.js | 138 KB | 91 KB (68%) | ✓ | 3rd |
| https://cdn.nos.nl/assets/nosnl/6bf4e31523fce2f86266c6f0560b31ac952c9171/_next/static/chunks/6342-d576b862fe5453f6.js | 114 KB | 88 KB (77%) | ✓ | 3rd |
| https://cdn.nos.nl/assets/nosnl/6bf4e31523fce2f86266c6f0560b31ac952c9171/_next/static/chunks/6342-d576b862fe5453f6.js | 0 KB | 88 KB (77%) | ✓ | 3rd |
| https://cdn.nos.nl/assets/nosnl/6bf4e31523fce2f86266c6f0560b31ac952c9171/_next/static/chunks/5798-9068d6e5e7b07025.js | 0 KB | 87 KB (59%) | ✓ | 3rd |
| https://cdn.nos.nl/assets/nosnl/6bf4e31523fce2f86266c6f0560b31ac952c9171/_next/static/chunks/5798-9068d6e5e7b07025.js | 148 KB | 87 KB (59%) | ✓ | 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
FPage Weight InventoryAction134 resources · 4.5 MB · 2.2 MB savings availableFIX
~2.2 MiB of savings available
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 134 resources | 4.5 MiB | ||||||
BImage Optimization39 images, 0 KB saveableREVIEW
CGreen HostingActionWhether the site is served from green-energy infrastructureREVIEW
Green Hosting
No green hosting detected
BHTTP Cachingpublic, s-maxage=1, stale-while-revalidate=600, stale-if-error=86400REVIEW
public, s-maxage=1, stale-while-revalidate=600, stale-if-error=86400
| Directive | Value | Meaning |
|---|---|---|
| public | — | Any cache may store this response |
| s-maxage | 1 | CDN caches for 1 second |
| stale-while-revalidate | 600 | Serve stale for 10 minutes while fetching fresh |
| stale-if-error | 86400 |
A+Text CompressionAll text resources are compressedPASS
A+Font Loading1 fonts (64 KB)PASS
Web fonts
1
64 KB total
Render-blocking
0
of 1
Dominant font-display
swap
Most common across fonts
Font loading timeline
- Convert to woff2 for ~30% smaller file size
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)
Fixing the unchecked items could save ~19 KB and ~38 ms
A+Resource CachingAll resources properly cachedPASS
A+Critical Rendering PathNo render-blocking resourcesPASS
A+Resource Hints31 hints, 0 missing preconnectsPASS
Current Resource Hints
31 resource hints configured
A+Render-Blocking ResourcesNo render-blocking resources detectedPASS
A+Third-Party ResourcesNo third-party resources detectedPASS
Network Waterfall134 requests over 5235msINFO
Third-Party Script CostPer-script blocking time, transfer cost, and cache headersINFO
| Script | Category | Execution | Transfer | Unused | Monthly Cost | Verdict |
|---|---|---|---|---|---|---|
cdn.nos.nl cdn.nos.nl | Other | 882ms | 186 KB | 41% | €10/mo | Costly |
Unattributable Unattributable | Other | 790ms | 0 KB | — | €9/mo | Costly |
cdn.nos.nl cdn.nos.nl | Other | 675ms | 32 KB | — | €7/mo | Costly |
cdn.nos.nl cdn.nos.nl | Other | 435ms | 215 KB | 45% | €5/mo | Costly |
cdn.nos.nl cdn.nos.nl | Other | 384ms | 0 KB | 58% | €4/mo | Costly |
cdn.nos.nl cdn.nos.nl | Other | 261ms | 499 KB | 53% | €3/mo | Costly |
cdn.nos.nl cdn.nos.nl | Other | 68ms | 0 KB | 73% | €1/mo | Optional |
cdn.nos.nl cdn.nos.nl | Other | 57ms | 0 KB | — | €1/mo | Optional |
cdn.nos.nl cdn.nos.nl | Other | 56ms | 471 KB | 89% | €1/mo | Optional |
cookies.nos.nl cookies.nos.nl | Other | 51ms | 6 KB | — | €1/mo | Optional |
These scripts may cost more than they're worth
- cdn.nos.nl adds 882ms and costs ~€10/month
- Unattributable adds 790ms and costs ~€9/month
- cdn.nos.nl adds 675ms and costs ~€7/month
- cdn.nos.nl adds 435ms and costs ~€5/month
- cdn.nos.nl adds 384ms and costs ~€4/month
- cdn.nos.nl adds 261ms and costs ~€3/month
86% 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
cdn.nos.nl takes 882ms 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 790ms 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
cdn.nos.nl takes 675ms 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
cdn.nos.nl takes 435ms 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
cdn.nos.nl takes 384ms 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
58% of cdn.nos.nl'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
cdn.nos.nl takes 261ms 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
53% of cdn.nos.nl'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
73% of cdn.nos.nl'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
89% of cdn.nos.nl'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