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Швидкість і продуктивність — AISeen Docs

Як AISeen вимірює швидкість сайту: TTFB, розмір HTML, HTTP/2, стиснення gzip/brotli, Cache-Control та ETag.

What we check

⏱️TTFB (Time to First Byte)Critical

Target:< 800ms30 pts

Time from when the browser sends a request to when it receives the first byte of the response. High TTFB indicates slow server, no CDN, or expensive backend processing.

Good:< 400ms

Warn:400–800ms

Poor:> 800ms

Fix:Use a CDN (Cloudflare, Vercel, Fastly), enable edge caching, optimize database queries, or upgrade hosting.

📄HTML SizeHigh

Target:< 100KB15 pts

Size of the initial HTML document (uncompressed). Large HTML documents delay parsing and rendering, especially on mobile connections.

Good:< 50KB

Warn:50–100KB

Poor:> 100KB

Fix:Remove inline CSS/JS, split large pages, use server-side rendering with partial hydration, compress output.

🚀HTTP VersionHigh

Target:HTTP/2 or HTTP/315 pts

HTTP/2 enables multiplexing (parallel requests over one connection), header compression, and server push. HTTP/1.1 serializes requests, causing head-of-line blocking.

Good:HTTP/2 or HTTP/3

Warn:HTTP/1.1 with keepalive

Poor:HTTP/1.0 or HTTP/1.1 only

Fix:Enable HTTP/2 in your web server config (Nginx: http2 on; Apache: Protocols h2). Use a CDN — most support HTTP/2 by default.

🗜️Compression (gzip/brotli)High

Target:gzip or brotli enabled15 pts

Text compression reduces transfer size by 60–80%. Brotli achieves better ratios than gzip at similar CPU cost. Uncompressed HTML/CSS/JS causes unnecessary bandwidth usage and slower loads.

Good:brotli (br)

Warn:gzip only

Poor:No compression

Fix:Enable gzip or brotli in Nginx (gzip on; brotli on) or CDN settings. Vercel and Cloudflare compress automatically.

🗃️Cache-Control HeadersMedium

Target:Present on static assets10 pts

Cache-Control tells browsers and CDNs how long to store responses. Without caching, every visit re-downloads all assets, increasing load time and server cost.

Good:max-age ≥ 31536000 on assets

Warn:Short max-age or no-cache without revalidation

Poor:No Cache-Control header

Fix:Set Cache-Control: public, max-age=31536000, immutable on versioned assets. Use no-store for sensitive pages.

🏷️ETag / Last-ModifiedLow

Target:Present for revalidation5 pts

Conditional request headers that enable 304 Not Modified responses, allowing cached resources to be revalidated without re-downloading the full content.

Good:Both ETag and Last-Modified present

Warn:One of the two present

Poor:Neither present

Fix:Enable in Nginx (etag on; add_header Last-Modified ...) or verify your CDN or framework generates these by default.

🔗Resource HintsMedium

Target:preconnect/preload used10 pts

Resource hints in the <head> allow the browser to start DNS lookups, TCP connections, or asset downloads early. preconnect to your font or API CDN can save 150–300ms.

Good:preconnect to CDN + preload of critical assets

Warn:Some resource hints present

Poor:No resource hints

Fix:Add <link rel="preconnect" href="https://fonts.gstatic.com"> for external domains. Use <link rel="preload" as="font"> for critical fonts.

How scoring works

Each check has a point value. Pass/fail is determined by whether the metric meets the target threshold. TTFB is the most important signal and carries the highest weight.

⏱️ TTFB (Time to First Byte)30 pts

📄 HTML Size15 pts

🚀 HTTP Version15 pts

🗜️ Compression (gzip/brotli)15 pts

🗃️ Cache-Control Headers10 pts

🏷️ ETag / Last-Modified5 pts

🔗 Resource Hints10 pts

Total possible: 100 points. Partial credit given for TTFB (warning threshold scores 50% of full points).

Score ranges

80 – 100

Fast

Excellent server performance. TTFB under 400ms, compression enabled, HTTP/2, proper caching. Users and crawlers get fast responses.

50 – 79

Acceptable

Adequate speed but room for improvement. Some optimization opportunities available — likely missing compression or caching.

0 – 49

Slow

High TTFB and/or missing compression and caching. Likely hurting search rankings and user retention significantly.

Quick wins for better speed scores

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Put your site behind Cloudflare (free)

Cuts TTFB by 40–70%, adds HTTP/2, brotli, and caching automatically.

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Deploy on Vercel or Netlify Edge

Both serve from edge nodes globally, reducing TTFB to <100ms for most users.

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Add Cache-Control headers to static assets

Near-zero load time for returning visitors on cached resources.

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Enable brotli at the CDN or server level

Reduces HTML/CSS/JS transfer size by 60–80% with minimal CPU cost.

→

Add preconnect for external domains

Saves 150–300ms on DNS + TCP + TLS for third-party resources.

Швидкість і продуктивність — AISeen Docs

Як AISeen вимірює швидкість сайту: TTFB, розмір HTML, HTTP/2, стиснення gzip/brotli, Cache-Control та ETag.

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