Bootstrap vs Flat UI
Head-to-head usage across the sites we track.
Top sites by authority
Bootstrap · Flat UI · how many of each technology's sites sit in the web's highest authority tiers
Open Page Rank 9+
181
1
Open Page Rank 8+
3,822
15
Open Page Rank 7+
18,772
27
Open Page Rank 6+
39,549
37
Open Page Rank 5+
73,510
53
Open Page Rank scores 0 to 10 from the open web link graph; 9+ covers only a few hundred domains worldwide.
By country
Bootstrap · Flat UI · share of sites in each country using one or the other
United States
783,149
310
India
375,468
209
Germany
285,193
145
United Kingdom
258,945
215
Brazil
247,896
115
France
233,698
124
Italy
215,264
124
Canada
174,973
132
Audience countries from the Chrome UX Report, top markets of either technology.
Real user performance
| Metric | Bootstrap | Flat UI |
|---|---|---|
| LCP | 1.8 s | 2.1 s |
| INP | 75 ms | 75 ms |
| CLS | 0 | 0 |
| TTFB | 800 ms | 900 ms |
Median site's p75 values from the Chrome UX Report, Aug 2026. Lower is better; green meets Google's "good" threshold. This describes the sites that use each technology, not the technology's own overhead.
Sites that switched
Domains that dropped one technology and adopted the other within about a year, data nobody else gives away free.
Bootstrap to Flat UI
| Domain | When |
|---|---|
| wisconsinhealthnews.com | Nov 2025 |
Flat UI to Bootstrap
| Domain | When |
|---|---|
| wisconsinhealthnews.com | Nov 2025 |