How it's calculated
The Rendering Score is derived from the Ghost Ratio using a non-linear curve that penalises client-side rendering more heavily:
RenderingScore = round(100 × (1 − GhostRatio^1.5))
The 1.5 exponent means the penalty accelerates as ghost ratio increases:
- Ghost ratio 0.05 → Rendering Score 99
- Ghost ratio 0.15 → Rendering Score 94
- Ghost ratio 0.30 → Rendering Score 84
- Ghost ratio 0.50 → Rendering Score 65
- Ghost ratio 0.80 → Rendering Score 28
What Ghost Ratio measures
Ghost Ratio (0.0–1.0) is the estimated proportion of content that is "ghosted" — visible to browser users but invisible to AI crawlers that don't run JavaScript. SEODiff estimates this using framework detection and text density analysis, without running a headless browser.
Score interpretation
- 90–100: SSR — all content is in the HTML response. AI crawlers see everything.
- 70–89: Hybrid — most content is server-rendered, some requires JavaScript.
- 40–69: Partial CSR — significant content is JavaScript-dependent.
- Below 40: Full CSR — most content is invisible to AI crawlers.