Tip: Open DevTools → Network, disable cache, reload, and watch TTFB, content download, and waterfalls.

Modes

Fast (baseline)

Fast

TTFB delay (slow backend before first byte)

3s 8s

Streaming (trickles HTML over time)

6s stream

Large payload (heavy HTML/body)

2MB 8MB

CPU burn (expensive server computation)

3s CPU 10s CPU

Slow assets (CSS/JS/image are delayed)

Assets 2s Assets 6s

What this teaches in DevTools

TTFB: backend / DB / cache misses
Waterfall: render-blocking CSS/JS
Transfer size: payload bloat
Long tasks: CPU-bound code

Live page status

JS status: (no slow JS loaded)

Streaming mode enabled: trickling content for ~6000ms…

Chunk 1/12 — 8%

Chunk 2/12 — 17%

Chunk 3/12 — 25%

Chunk 4/12 — 33%

Chunk 5/12 — 42%

Chunk 6/12 — 50%

Chunk 7/12 — 58%

Chunk 8/12 — 67%

Chunk 9/12 — 75%

Chunk 10/12 — 83%

Chunk 11/12 — 92%

Chunk 12/12 — 100%

Server-side elapsed before footer: 6006ms (not the same as browser TTFB).