Performance
· 21 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.
1.27 s
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
1.27 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
1 ms
Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.
0.008
Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.
1.35 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.
2.33 s
Page Load Progression
DThird-Party ImpactAction100% third-party, 0 ms blockingFIX
FHTTP CachingActionNo cache headersFIX
No Cache-Control header
Adding a Cache-Control header can significantly improve repeat-visit performance.
CJS BundlesAction8 scripts, 243 KB unusedREVIEW
Downloaded but never executed on this page.
| Script | Size | Unused | Minified | Party |
|---|---|---|---|---|
| https://pagead2.googlesyndication.com/pagead/managed/js/adsense/m202605060101/show_ads_impl_fy2021.js?bust=31098378 | 177 KB | 147 KB (83%) | ✓ | 3rd |
| https://fundingchoicesmessages.google.com/i/ca-pub-8621957794194569?href=https%3A%2F%2Fwww.metafilter.com&ers=2 | 70 KB | 36 KB (52%) | ✓ | 3rd |
| https://dha92jo6cen2v.cloudfront.net/scripts/mefi/libscript20250324.2113.js | 49 KB | 33 KB (68%) | ✓ | 3rd |
| https://pagead2.googlesyndication.com/pagead/js/adsbygoogle.js | 54 KB | 26 KB (49%) | ✓ | 3rd |
| https://dha92jo6cen2v.cloudfront.net/scripts/mefi/pageload092414.mod.js | 7 KB | — | ✓ | 3rd |
| https://dha92jo6cen2v.cloudfront.net/scripts/mefi/members20250324.2113.js | 8 KB | — | ✓ | 3rd |
| https://www.metafilter.com/cdn-cgi/challenge-platform/h/g/scripts/jsd/fe6331af5207/main.js? | 10 KB | — | ✓ | 3rd |
| https://fundingchoicesmessages.google.com/f/AGSKWxWkx2MG3tmESKP7w6uBi247xNiJBAaslqx-8GaquJ3uCXcWPOtV7earFDlxg89YnRra54p4c3Zr3wJbe-2YTBTEuiHy18yxnMEQ1PZjkZBo7Ycvvgzc9LapsEnRZrmAJhmuOz3zzg==?fccs=W251bGwsbnVsbCxudWxsLG51bGwsbnVsbCxudWxsLFsxNzc4NDE5Mjc5LDU4NjAwMDAwMF0sbnVsbCxudWxsLG51bGwsW251bGwsWzddXSwiaHR0cHM6Ly93d3cubWV0YWZpbHRlci5jb20vIixudWxsLFtbOCwiUmlhcWJuU0k1ZWMiXSxbOSwiZW4tVVMiXSxbMTgsIltbW251bGwsODM3XV1dIl0sWzM1LCIxNzc4NDE5Mjc5Il0sWzE5LCIxIl0sWzE3LCJbMF0iXSxbMjQsIiJdLFsyOSwiZmFsc2UiXV1d | 68 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
CCompression AlgorithmActionMain response served uncompressedREVIEW
BMain HTML Cache-ControlNo Cache-Control header on main HTML responseREVIEW
BServer-Timing ObservabilityNo Server-Timing header foundREVIEW
BPage Weight Inventory30 resources · 644 KB · 243 KB savings availableREVIEW
~242.7 KiB of savings available
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 30 resources | 644.0 KiB | ||||||
A+Page Weight Budget644 KB transferred, 30 requestsPASS
A+Text CompressionAll text resources are compressedPASS
A+Image OptimizationNo images on this pagePASS
A+JS Execution Cost407ms total JS executionPASS
Main Thread Breakdown
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| https://www.metafilter.com/ | 217ms | 12ms | 2ms | 3rd |
| https://fundingchoicesmessages.google.com/f/AGSKWxWkx2MG3tmESKP7w6uBi247xNiJBAaslqx-8GaquJ3uCXcWPOtV7earFDlxg89YnRra54p4c3Zr3wJbe-2YTBTEuiHy18yxnMEQ1PZjkZBo7Ycvvgzc9LapsEnRZrmAJhmuOz3zzg==?fccs=W251bGwsbnVsbCxudWxsLG51bGwsbnVsbCxudWxsLFsxNzc4NDE5Mjc5LDU4NjAwMDAwMF0sbnVsbCxudWxsLG51bGwsW251bGwsWzddXSwiaHR0cHM6Ly93d3cubWV0YWZpbHRlci5jb20vIixudWxsLFtbOCwiUmlhcWJuU0k1ZWMiXSxbOSwiZW4tVVMiXSxbMTgsIltbW251bGwsODM3XV1dIl0sWzM1LCIxNzc4NDE5Mjc5Il0sWzE5LCIxIl0sWzE3LCJbMF0iXSxbMjQsIiJdLFsyOSwiZmFsc2UiXV1d | 70ms | 35ms | 9ms | 3rd |
| https://www.metafilter.com/cdn-cgi/challenge-platform/scripts/jsd/main.js | 70ms | 66ms | 1ms | 3rd |
| https://fundingchoicesmessages.google.com/i/ca-pub-8621957794194569?href=https%3A%2F%2Fwww.metafilter.com&ers=2 | 51ms | 46ms | 4ms | 3rd |
A+Font Loading6 fonts (115 KB)PASS
Web fonts
6
115 KB total
Render-blocking
0
of 6
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
A+HTTP/3 (QUIC)HTTP/3 advertised via Alt-SvcPASS
A+LCP Image PreloadLCP preload audit not availablePASS
A+Server Response Intelligence1 server-response signal(s) detectedPASS
A+Green HostingWhether the site is served from green-energy infrastructurePASS
Green Hosting
This site is hosted on green energy infrastructure
Provider: Cloudflare
Network Waterfall30 requests over 1498msINFO
Third-Party Script CostPer-script blocking time, transfer cost, and cache headersINFO
| Script | Category | Execution | Transfer | Unused | Monthly Cost | Verdict |
|---|---|---|---|---|---|---|
www.metafilter.com www.metafilter.com | Other | 217ms | 22 KB | — | €2/mo | Costly |
fundingchoicesmessages.google.com fundingchoicesmessages.google.com | Other | 70ms | 68 KB | — | €1/mo | Optional |
www.metafilter.com www.metafilter.com | Other | 70ms | 0 KB | — | €1/mo | Optional |
fundingchoicesmessages.google.com fundingchoicesmessages.google.com | Other | 51ms | 70 KB | 52% | €1/mo | Optional |
These scripts may cost more than they're worth
- www.metafilter.com adds 217ms 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.metafilter.com takes 217ms 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
52% of fundingchoicesmessages.google.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