www.ycombinator.com

The numbers

First visit

5.03 g CO₂e

Return visit

0.0072 g CO₂e

Hosting

unknown

LCP

2.09 s

CLS

0.011

TTFB

972 ms

At 10,000 views a month this page emits about 453.1 kg CO₂e a year, roughly 1857 km in an average petrol car. The estimate assumes 75% new and 25% returning visitors, a measured cache reload ratio of 0%, and world-average grid intensity. How we calculate this

1. Convert and compress imagessave ~1.31 g/visit (11.79 MB)High impact · quick fix

   114 images (26.20 MB) 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.

   • harshita-arora-now-compressed-9c9b8a5f8f07ac5…1.92 MB
   • replit-now-3-03e7f981faef0a67ca9ba3b60f41f91a…1.32 MB
   • diana-hu-now-1-compressed-55e1804ed97a33d8724…947 kB
   • scale-ai-batch3-cac949deabf5b818c3f3f2c49d9e2…894 kB
   • harshita-arora-batch-compressed-7fdeb1ee3c741…829 kB

   WSG 2.9: Optimize media to reduce resource use
2. Defer video and audiosave ~0.409 g/visit (3.68 MB)High impact · quick fix

   4.60 MB of audio/video downloads during initial page load; 9 videos preload data without preload="none".

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

   • tony-xu-video-compressed-cfaffb21fca0c9e88fb5…711 kB
   • sam-altman-video-compressed-6e99f4927d081ecef…562 kB
   • emmett-shear-video-compressed-e639d24c15750fb…543 kB
   • michael-truell-video-compressed-523ea9b5330b3…501 kB
   • greg-brockman-video-compressed-cb96007824e30f…496 kB

   WSG 2.9: Optimize media to reduce resource use
3. Serve images at the size they displaysave ~0.376 g/visit (3.38 MB)High impact · quick fix

   20 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.

   • scale-ai-batch3-cac949deabf5b818c3f3f2c49d9e2…894 kB
   • airbnb-batch-2-a1df9c49bacc25254fe05a3bac4921…704 kB
   • replit-batch-1-1fa8581e2ab474b5475f0ba9ef36c5…698 kB
   • instacart-batch-2-c4d5c8eea73e1c85e472b9b3fa9…652 kB
   • coinbase-batch-1-d0d5c84104f9f9578d888d283099…577 kB

   WSG 2.9: Optimize media to reduce resource use
4. Reduce JavaScript payloadsave ~0.075 g/visit (673 kB)High impact · moderate effort

   350 scripts total 2.69 MB on the wire (7.94 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.

   • js383 kB
   • giphy-BBtdW07P.js172 kB
   • js161 kB
   • agent.umd.js121 kB
   • renderMarkdown-CufAi7g-.js118 kB

   WSG 3.2: Minify and remove unused codeWSG 3.3: Modularize bandwidth-heavy components
5. Audit third-party servicessave ~0.060 g/visit (542 kB)High impact · moderate effort

   14 third-party domains account for 1.08 MB (3% 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.

   • maps.googleapis.com383 kB
   • fonts.gstatic.com286 kB
   • www.googletagmanager.com161 kB
   • cdn.dfsdk.com121 kB
   • app.posthog.com72 kB
   • us-assets.i.posthog.com35 kB

   WSG 3.5: Treat third parties the same as first parties
6. Verify your hosting energyMedium impact · moderate effort

   This host has not published renewable energy evidence with the Green Web Foundation, so its energy source is unknown.

   Choose a provider listed in the Green Web Directory, or ask your current provider to publish evidence (and a carbon.txt). This cuts the data-center share of every single page view.

   • carbon.txtNo carbon.txt found at the site root; publishing one is the lightest first step.

   WSG 4.1: Use sustainable hosting
7. Upgrade compression beyond gzipsave ~0.025 g/visit (222 kB)Advisory · quick fix

   1.48 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.

   • js383 kB
   • CartesianChart-CSDlSyuK.js87 kB
   • index.esm-CruaG2mc.js61 kB
   • client-EmpKkt63.js58 kB
   • ycombinator.com48 kB

   WSG 4.3: Reduce data transfer with compression
8. Optimize web fontssave ~0.011 g/visit (100 kB)Advisory · quick fix

   3 font files total 286 kB.

   Subset fonts to used glyphs, prefer one variable font over multiple weights, serve WOFF2 only, and consider system fonts for UI text.

   • vEFK2_tTDB4M7-auWDN0ahZJW1gewtW_Wg.woff2130 kB
   • vEFI2_tTDB4M7-auWDN0ahZJW1gb8tc.woff2123 kB
   • QGYvz_MVcBeNP4NJtEtq.woff233 kB

   WSG 2.11: Use optimized web typography
9. Set a page-weight budgetAdvisory · moderate effort

   At 33.95 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. 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.

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

    The page renders 1577 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

• Images26.20 MB · 115 req
• Audio / video4.60 MB · 9 req
• JavaScript2.69 MB · 350 req
• Fonts286 kB · 3 req
• CSS134 kB · 26 req
• HTML48 kB · 1 req
• Data (fetch)2.0 kB · 4 req
• Other552 B · 1 req
• Data (XHR)83 B · 2 req

Trend