Based on 1637 and 88 real audits
| Metric | core-js | Siteimprove | Winner |
|---|---|---|---|
| Performance | 36 | 35 | core-js |
| Accessibility | 88 | 95 | Siteimprove |
| Best Practices | 84 | 86 | Siteimprove |
| SEO | 91 | 94 | Siteimprove |
| Security | 65 | 64 | core-js |
| TTFB | 385ms | 544ms | core-js |
| Composite | 73 | 72 | core-js |
core-js outperforms Siteimprove in 4 of 7 categories, with a stronger composite score (73 vs 72). Siteimprove leads in accessibility, best practices, SEO.
Choose core-js when your primary concern is server response time and performance. Its audit data shows consistent strength in these areas across the sampled sites.
Choose Siteimprove when your primary concern is accessibility and SEO. Its audit data shows consistent strength in these areas across the sampled sites.
Scores are medians across 1637 audited core-js sites and 88 audited Siteimprove sites in the BeaverCheck database. Every audit runs the same 100+ checks — Lighthouse performance, security headers, accessibility, SEO, server response time — against a real URL. No vendor input, no sponsorship, no affiliate links. Read the full methodology →
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