https://instagramstoryviewer.cc
Performance
· 26 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.SCORE
91
GRADE
A
FIX
1
REVIEW
7
PASS
15
INFO
3
Performance-focused optimization plan with CWV assessment, top offenders, and time estimates
72
95
81
100
First Contentful Paint First Contentful Paint — how long until the browser renders the first piece of content. Under 1.8s is good.
1.57 s
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
5.20 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
291 ms
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.
4.00 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.
5.20 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 sChecks
2615 PASS 7 REVIEW 1 FIX
FHTTP CachingActionNo cache headersFIX
HTTP Caching
ActionNo cache headers
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.
CJS Execution CostAction1254ms total JS executionREVIEW
JS Execution Cost
Action1254ms total JS execution
1254ms total JS execution
Warning::
https://instagramstoryviewer.cc/: 407ms CPU time
Warning::
https://instagramstoryviewer.cc/cdn-cgi/challenge-...: 280ms CPU time
Warning::
https://www.googletagmanager.com/gtag/js?id=G-LE67...: 279ms CPU time
Info::
https://instagramstoryviewer.cc/assets/framework-D...: 149ms CPU time
Info::
Unattributable: 140ms CPU time
Info::
Third-party scripts: 279ms (22% of total)
Main Thread Breakdown
Script Evaluation 52% Style & Layout 24% Other 15% Script Parsing & Compilation 4% Rendering 3%
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| https://instagramstoryviewer.cc/ | 407ms | 38ms | 5ms | 1st |
| https://instagramstoryviewer.cc/cdn-cgi/challenge-platform/scripts/jsd/main.js | 280ms | 262ms | 3ms | 1st |
| https://www.googletagmanager.com/gtag/js?id=G-LE67EY6MM1 | 279ms | 237ms | 40ms | 3rd |
| https://instagramstoryviewer.cc/assets/framework-DjPHiq1u.js | 149ms | 119ms | 1ms | 1st |
| Unattributable | 140ms | 10ms | 0ms | 1st |
BJS Bundles9 scripts, 98 KB unusedREVIEW
JS Bundles
9 scripts, 98 KB unused
9 scripts, 98 KB unused
Warning::
https://www.googletagmanager.com/gtag/js?id=G-LE67...: 72 KB unused (41%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://instagramstoryviewer.cc/assets/framework-D...: 26 KB unused (45%)
Consider code splitting or tree shaking to reduce unused code.
Info::
Total unused JavaScript: 98 KB
98 KB unused JavaScript
Downloaded but never executed on this page.
| Script | Size | Unused | Minified | Party |
|---|---|---|---|---|
| https://www.googletagmanager.com/gtag/js?id=G-LE67EY6MM1 | 176 KB | 72 KB (41%) | ✓ | 3rd |
| https://instagramstoryviewer.cc/assets/framework-DjPHiq1u.js | 58 KB | 26 KB (45%) | ✓ | 1st |
| https://instagramstoryviewer.cc/assets/layout-segment-context-D5cMo-KD.js | 0 KB | — | ✓ | 1st |
| https://instagramstoryviewer.cc/assets/rolldown-runtime-S-ySWqyJ.js | 0 KB | — | ✓ | 1st |
| https://instagramstoryviewer.cc/assets/index-r7lsyBqO.js | 24 KB | — | ✓ | 1st |
| https://instagramstoryviewer.cc/assets/page-D_Vwn2-Q.js | 4 KB | — | ✓ | 1st |
| https://instagramstoryviewer.cc/assets/link-vHCogT2p.js | 4 KB | — | ✓ | 1st |
| https://instagramstoryviewer.cc/assets/script-BCQCzhfo.js | 1 KB | — | ✓ | 1st |
| https://instagramstoryviewer.cc/cdn-cgi/challenge-platform/h/g/scripts/jsd/4df4a60fa397/main.js? | 12 KB | — | ✓ | 1st |
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
BHTTP/3 (QUIC)HTTP/3 not advertisedREVIEW
HTTP/3 (QUIC)
HTTP/3 not advertised
HTTP/3 not advertised
Info::
HTTP/3 (QUIC) is not advertised
HTTP/3 isn't advertised via Alt-Svc and the worker didn't negotiate h3. HTTP/3 reduces handshake latency (1-RTT instead of 2-3 RTTs) and is more resilient on lossy connections. Most modern CDNs (Cloudflare, Fastly, AWS CloudFront, Google Cloud CDN) support HTTP/3 with a single config switch -- consider enabling for mobile-heavy workloads.
BDocument CompressionDocument response uses gzip; brotli would be ~20% smallerREVIEW
Document Compression
Document response uses gzip; brotli would be ~20% smaller
Document response uses gzip; brotli would be ~20% smaller
Info::
Main HTML response uses gzip (brotli would be ~20% smaller)
All current browsers support brotli. Most CDNs (Cloudflare, Fastly, AWS CloudFront, Vercel, Netlify) can switch from gzip to brotli with a single config flag. Origin servers (nginx, Apache) need a brotli module compiled in -- nginx-brotli or Apache mod_brotli.
BMain HTML Cache-ControlNo Cache-Control header on main HTML responseREVIEW
Main HTML Cache-Control
No Cache-Control header on main HTML response
No Cache-Control header on main HTML response
Info::
Main HTML response has no Cache-Control header
Without an explicit Cache-Control, browsers fall back to heuristic caching (~10% of Last-Modified age). Set `Cache-Control: no-cache` or `max-age=300` for HTML to control freshness explicitly -- prevents stale auth state and SPA shell drift.
BServer-Timing ObservabilityNo Server-Timing header foundREVIEW
Server-Timing Observability
No Server-Timing header found
No Server-Timing header found
Info::
No Server-Timing header found
Server-Timing exposes backend timing breakdowns to browser DevTools (e.g., `db: 45ms; render: 120ms; cache: 2ms`). Useful for diagnosing slow pages without backend log access. Most modern frameworks (Next.js, Cloudflare Workers, Fastly) emit it automatically; absence on a managed platform usually means telemetry headers are stripped at the edge.
CGreen HostingActionWhether the site is served from green-energy infrastructureREVIEW
Green Hosting
ActionWhether the site is served from green-energy infrastructure
Green Hosting
No green hosting detected
A+Page Weight Budget443 KB transferred, 27 requestsPASS
Page Weight Budget
443 KB transferred, 27 requests
443 KB transferred, 27 requests
Info::
Page weighs 1.0 MB (443 KB transferred)
Info::
27 HTTP requests
Info::
Estimated 0.09 g CO2 per page load
443 KB transferred
27 requests
0.09 g CO2 per page load
JavaScript 280.0 KiB 63%
Fonts 144.1 KiB 33%
HTML 8.3 KiB 2%
CSS 5.9 KiB 1%
Other 2.3 KiB 1%
Other 1.2 KiB 0%
Other 875 B 0%
0 2.4 MB 4.9 MB
Under budget
AThird-Party Impact40% third-party, 0 ms blockingPASS
Third-Party Impact
40% third-party, 0 ms blocking
40% third-party, 0 ms blocking
Info::
Third-party code accounts for 40% of page weight (176.2 KiB of 442.7 KiB)
Info::
Third-party blocking time is low (0 ms)
60%
40%
First-party Third-party
A+Text CompressionAll text resources are compressedPASS
Text Compression
All text resources are compressed
All text resources are compressed
Info::
All text resources are compressed
All text resources are properly compressed.
A+Image OptimizationNo images on this pagePASS
Image Optimization
No images on this page
No images on this page
Info::
No images on this page
0 images 0 KB
0 oversized -0 KB
0 legacy format
0 missing dimensions CLS risk
A+Font Loading11 fonts (144 KB)PASS
Font Loading
11 fonts (144 KB)
11 fonts (144 KB)
Info::
11 font(s) use font-display: swap (FOUT risk but functional)
Web fonts
11
144 KB total
Render-blocking
0
of 11
Dominant font-display
swap
Most common across fonts
Font loading timeline
Transfer FOIT (block) FOUT (swap)
geist-ff2310f5.woff2 woff2 swap
Size 7 KB
Load time 187 ms
Start 111 ms
Risk FOUT — text flashes from fallback to web font
geist-875ccdd4.woff2 woff2 swap
Size 15 KB
Load time 190 ms
Start 112 ms
Risk FOUT — text flashes from fallback to web font
geist-52306abf.woff2 woff2 swap
Size 8 KB
Load time 195 ms
Start 112 ms
Risk FOUT — text flashes from fallback to web font
geist-001175b1.woff2 woff2 swap
Size 16 KB
Load time 187 ms
Start 112 ms
Risk FOUT — text flashes from fallback to web font
geist-98bbbccb.woff2 woff2 swap
Size 29 KB
Load time 212 ms
Start 112 ms
Risk FOUT — text flashes from fallback to web font
geist-mono-f6b33328.woff2 woff2 swap
Size 6 KB
Load time 194 ms
Start 113 ms
Risk FOUT — text flashes from fallback to web font
geist-mono-44e03052.woff2 woff2 swap
Size 13 KB
Load time 203 ms
Start 113 ms
Risk FOUT — text flashes from fallback to web font
geist-mono-0638449e.woff2 woff2 swap
Size 6 KB
Load time 202 ms
Start 113 ms
Risk FOUT — text flashes from fallback to web font
geist-mono-971fb274.woff2 woff2 swap
Size 8 KB
Load time 225 ms
Start 113 ms
Risk FOUT — text flashes from fallback to web font
geist-mono-44745446.woff2 woff2 swap
Size 14 KB
Load time 213 ms
Start 113 ms
Risk FOUT — text flashes from fallback to web font
geist-mono-013b2f2f.woff2 woff2 swap
Size 23 KB
Load time 218 ms
Start 114 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 CachingAll resources properly cachedPASS
Resource Caching
All resources properly cached
All resources properly cached
Info::
No caching issues found
All static resources have appropriate caching headers.
A+Critical Rendering PathNo render-blocking resourcesPASS
Critical Rendering Path
No render-blocking resources
No render-blocking resources
Info::
No render-blocking resources detected
A+Resource Hints11 hints, 0 missing preconnectsPASS
Resource Hints
11 hints, 0 missing preconnects
11 hints, 0 missing preconnects
Info::
Page uses 11 resource hint(s)
Current Resource Hints
preconnect—
preload
+1
11dns-prefetch—
prefetch—
11 resource hints configured
A+LCP Image PreloadLCP preload audit not availablePASS
LCP Image Preload
LCP preload audit not available
LCP preload audit not available
Info::
LCP image preload audit not available for this scan
A+Server Response Intelligence2 server-response signal(s) detectedPASS
Server Response Intelligence
2 server-response signal(s) detected
2 server-response signal(s) detected
Info::
`Vary` header declared: RSC, Accept, Next-Router-State-Tree, Next-Router-Prefetch, Next-Router-Segment-P...
The page declares a `Vary` header, telling downstream caches which request headers the response varies on. Critical for content-negotiated responses (compression, language, cookies, device class).
Info::
No `ETag` or `Last-Modified` -- conditional GET not supported
Without either header, browsers can't issue conditional GETs and refresh always re-downloads the full response body even when nothing changed. Add `ETag: "<hash>"` (or `Last-Modified: <date>`) on cacheable responses; the server returns 304 Not Modified when the client's cached copy is still valid, saving bandwidth.
A+Page Weight Inventory27 resources · 443 KB · 98 KB savings availablePASS
Page Weight Inventory
27 resources · 443 KB · 98 KB savings available
27 resources · 443 KB · 98 KB savings available
Info::
Within 1MB page-weight target
Got: 443 KB
Info::
~98 KB of savings available
Info::
2 third-party resources (40% of weight)
27 resources · 442.7 KiB · 2 third-party Within 1MB page-weight target
JavaScript 63% · 280.0 KiB
Font 33% · 144.1 KiB
Document 2% · 8.3 KiB
CSS 1% · 5.9 KiB
Other 1% · 3.9 KiB
Image 0% · 478 B
~98.1 KiB of savings available
Remove unused JavaScript: 98.1 KiB
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 27 resources | 442.7 KiB | ||||||
A+Render-Blocking ResourcesNo render-blocking resources detectedPASS
Render-Blocking Resources
No render-blocking resources detected
No render-blocking resources detected
Info::
No render-blocking resources detected in <head>
A+Third-Party ResourcesNo third-party resources detectedPASS
Third-Party Resources
No third-party resources detected
No third-party resources detected
AJavaScript Blocking1 JS blocking issue(s) detectedPASS
JavaScript Blocking
1 JS blocking issue(s) detected
1 JS blocking issue(s) detected
Warning::
1 render-blocking <script src> tag(s) without async/defer
Each `<script src=...>` without `async`, `defer`, or `type="module"` blocks HTML parsing while the browser fetches and executes it. The block lasts the entire round-trip + execution time -- on slow networks this translates directly into LCP delay. Add `defer` (executes after parse, in source order) for scripts that interact with the DOM, or `async` (executes whenever ready) for analytics / independent scripts. Module scripts (`type="module"`) are deferred by default.
A+CSS Performance DepthNo CSS performance depth issues detectedPASS
CSS Performance Depth
No CSS performance depth issues detected
No CSS performance depth issues detected
Info::
No CSS performance depth issues detected
Asset CompressionNo text asset hosts to measureINFO
Asset Compression
No text asset hosts to measure
No text asset hosts to measure
Info::
No third-party or subdomain host served enough text assets to measure
Asset compression is measured per host, from one HEAD request against a sampled resource. Pages that serve all their JS and CSS from the document's own origin are covered by the document compression check instead.
Network Waterfall27 requests over 2350msINFO
Network Waterfall
27 requests over 2350ms
HTML JavaScript CSS Images Fonts XHR/Fetch Other
Third-Party Script CostPer-script blocking time, transfer cost, and cache headersINFO
Third-Party Script Cost
Per-script blocking time, transfer cost, and cache headers
22% of JavaScript execution is third-party
First-party Third-party 279ms · 176KB · €3/mo
| Script | Category | Execution | Transfer | Unused | Monthly Cost | Verdict |
|---|---|---|---|---|---|---|
Google Tag Manager www.googletagmanager.com | Tag Manager | 279ms | 176 KB | 41% | €3/mo | Costly |
Google Tag Manager
Tag Manager
Execution 279ms
Transfer 176 KB
Unused 41%
Monthly Cost €3/mo
These scripts may cost more than they're worth
- Google Tag Manager adds 279ms and costs ~€3/month
Google Tag Manager takes 279ms 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
All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.