Technical
TechnicalLow

HTML Document Size

Checks that the initial HTML payload is under 1MB.

What this check measures

We measure the raw HTML response size. Over 1MB is flagged — usually the result of massive inline JSON, SSR'd server state, or embedded images as data URIs.

Why it matters

Large HTML slows TTFB and parsing. On mobile, every extra 100KB of HTML adds ~200ms to first paint. Better: ship minimal HTML and fetch data client-side.

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How our audit detects it

Measure size of the raw HTML response body. Flag over 1 MB.

Typical findings

  • error_outline2MB+ HTML because SSR dumps all CMS data inline.
  • error_outlineBase64-encoded images in HTML instead of <img src>.

How to fix

Move large JSON to separate API endpoints (fetched client-side after first paint). Use img tags with src URLs, not data: URIs. Minify HTML if not already.

Frequently asked questions

Is server-state hydration the problem?expand_more
Often — frameworks dump full state into a <script>. Consider partial hydration or fetch-after-hydrate patterns.

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