Signal 04 of 09 · Nebula Diagnostic Spec v1.0.0
Load Speed
Does the page become useful quickly enough to keep paid visitors from bouncing?
Decision rule
Main content must reach usable state fast enough on a constrained connection. A run inspects render-blocking behavior, oversized hero media, and late-loading primary content, then reports measured values against the required threshold for the specific finding.
What the engine inspects
- ·render-blocking resource count
- ·hero image weight and format
- ·when primary content becomes visible
How to check it yourself
- In DevTools, throttle the network to Fast 3G and reload the page.
- Note when the main content becomes usable rather than merely painted.
- Inspect the Network tab for render-blocking scripts and oversized hero media; both push usable state past threshold.
The engine automates this inspection and attaches measured evidence to every failing condition. A manual pass is not a substitute for the recorded evidence trail, but it should agree with it.
Pass / fail examples
Pass
Primary content paints early; hero image is sized and compressed for mobile. Within threshold. Clear.
Fail
A multi-megabyte autoplay video delays first meaningful content well past the threshold recorded in the finding. Flagged.