www.shazam.com

The numbers

First visit

1.31 g CO₂e

Return visit

0.657 g CO₂e

Hosting

verified green

LCP

352 ms

CLS

0

TTFB

12 ms

At 10,000 views a month this page emits about 137.6 kg CO₂e a year, roughly 564 km in an average petrol car. The estimate assumes 75% new and 25% returning visitors, a measured cache reload ratio of 50%, and world-average grid intensity. How we calculate this

1. Audit third-party servicessave ~0.492 g/visit (4.64 MB)High impact · moderate effort

   5 third-party domains account for 9.29 MB (86% of the page).

   Remove services that no longer earn their place; load the rest on interaction (facades for embeds, delayed consent-gated tags). Each third party is also a privacy and performance dependency.

   • mvod.itunes.apple.com8.50 MB
   • is1-ssl.mzstatic.com632 kB
   • js-cdn.music.apple.com152 kB
   • api.music.apple.com5.2 kB
   • play-edge.itunes.apple.com2.8 kB

   WSG 3.5: Treat third parties the same as first parties
2. Defer video and audiosave ~0.450 g/visit (4.25 MB)High impact · quick fix

   8.50 MB of audio/video downloads during initial page load.

   Never autoload media: use preload="none" with a poster image, load players on interaction, and stream in an efficient codec (AV1/HEVC).

   • P1177167543_A1837464152_MV_video_gr290_sdr_19…4.80 MB
   • P1177167543_A1837464152_MV_video_gr280_sdr_19…3.38 MB
   • P1177167543_A1837464152_audio_en_gr256_mp4a-4…190 kB
   • P1177167543_A1837464152_MV_video_gr203_sdr_56…84 kB
   • P1177167543_A1837464152_audio_en_gr32_mp4a-40…26 kB

   WSG 2.9: Optimize media to reduce resource use
3. Fix caching for returning visitorssave ~0.152 g/visit (1.25 MB)High impact · quick fix

   On a repeat visit 5.01 MB of static assets were re-downloaded instead of coming from cache.

   Serve static assets with Cache-Control: public, max-age=31536000, immutable and versioned filenames so returning visitors download almost nothing.

   • P1177167543_A1837464152_MV_video_gr290_sdr_19…Cache-Control: private · 5.00 MB
   • playlist.m3u8Cache-Control: private, no-cache, no-store, no-transform, must-revalidate, max-age=0 · 2.8 kB
   • 140x140bb.webpCache-Control: max-age=655008, no-transform · 284 B
   • 4272a6849b16577e.cssCache-Control: max-age=86400 · 213 B
   • 25b307453fcfd3b2.cssCache-Control: max-age=86400 · 213 B

   WSG 4.2: Optimize caching and support offline access
4. Reduce JavaScript payloadsave ~0.025 g/visit (234 kB)High impact · moderate effort

   33 scripts total 938 kB on the wire (2.71 MB decoded). Bundles this size usually carry a lot of unused code.

   Split bundles per route, tree-shake dependencies, and audit with a bundle analyzer or coverage profile. A 25% cut is a conservative target for bundles this size.

   • script.js224 kB
   • musickit.js141 kB
   • b536a0f1-6d212236755ddbf0.js126 kB
   • 430e88be-ff721fdddbbe028f.js85 kB
   • 4bd1b696-182b6b13bdad92e3.js55 kB

   WSG 3.2: Minify and remove unused codeWSG 3.3: Modularize bandwidth-heavy components
5. Convert and compress imagessave ~0.020 g/visit (187 kB)Medium impact · quick fix

   12 images (415 kB) ship in legacy formats (JPEG/PNG/GIF).

   Serve AVIF (or WebP) with responsive srcset sizes, and re-compress oversized files. AVIF typically halves JPEG weight at the same visual quality.

   • 400x400bb.jpg57 kB
   • 640x360bb.jpg56 kB
   • 400x400bb.jpg54 kB
   • sprite.webp53 kB
   • 400x400bb.jpg52 kB

   WSG 2.9: Optimize media to reduce resource use
6. Enable text compressionsave ~0.017 g/visit (157 kB)Medium impact · quick fix

   1 text resource (224 kB) are served without gzip/Brotli.

   Enable Brotli (or at least gzip) on the server or CDN for HTML, CSS, JavaScript, JSON and SVG. Typical reduction is ~70%.

   • script.js224 kB

   WSG 4.3: Reduce data transfer with compression
7. Serve images at the size they displaysave ~0.0083 g/visit (78 kB)Medium impact · quick fix

   3 images are encoded at more than twice the pixels the layout shows, even accounting for this viewport's pixel density.

   Generate multiple sizes and let the browser pick with srcset/sizes; a 4000px original behind a 400px slot spends bandwidth no screen displays.

   • group-2026.webp70 kB
   • sprite.webp53 kB
   • sprite.webp53 kB

   WSG 2.9: Optimize media to reduce resource use
8. Upgrade compression beyond gzipsave ~0.020 g/visit (186 kB)Advisory · quick fix

   1.24 MB of text ships gzip-compressed; Brotli or Zstandard would cut roughly another 15-20%, and browsers without them fall back to gzip automatically.

   Serve precompressed Brotli for static text assets (highest level, compressed at build time) and enable Brotli or zstd for dynamic responses; keep gzip only as the fallback.

   • shazam.com417 kB
   • musickit.js141 kB
   • b536a0f1-6d212236755ddbf0.js126 kB
   • 430e88be-ff721fdddbbe028f.js85 kB
   • 4bd1b696-182b6b13bdad92e3.js55 kB

   WSG 4.3: Reduce data transfer with compression
9. Set a page-weight budgetAdvisory · moderate effort

   At 10.82 MB per view this page rates F. The findings above list where the weight is.

   Agree a transfer budget (e.g. under 975 kB reaches a B), enforce it in CI, and re-scan after each change to hold the line.

   WSG 3.1: Set goals based on performance and energy impact
10. Remove the entry redirectAdvisory · quick fix

    The address that was scanned goes through 1 redirect before the document is served, ending at https://www.shazam.com/. Every hop is a full round trip on a connection that has not warmed up yet.

    Point links, sitemaps and canonical tags at the final address, and make the host redirect in one hop rather than chaining http to https to www.

    • https://shazam.com/redirects to https://www.shazam.com/

    WSG 4.4: Setup necessary error pages and redirection links
11. Simplify the document structureAdvisory · larger effort

    The page renders 3176 DOM elements, above the 1,500 guideline. Large trees cost memory and CPU on every visitor's device.

    Flatten wrapper markup, render long lists virtually or paginate, and prefer semantic elements over nested divs.

    WSG 3.6: Ensure code follows good semantic practices

Where the bytes are

• Audio / video8.50 MB · 16 req
• JavaScript938 kB · 33 req
• Images782 kB · 58 req
• HTML417 kB · 1 req
• CSS106 kB · 21 req
• Fonts74 kB · 3 req
• Data (fetch)6.4 kB · 5 req
• Other0 B · 2 req