Based on 1840 and 218 real audits
| Metric | core-js | Underscore.js | Winner |
|---|---|---|---|
| Performance | 37 | 40 | Underscore.js |
| Accessibility | 88 | 88 | Tie |
| Best Practices | 85 | 85 | Tie |
| SEO | 91 | 91 | Tie |
| Security | 67 | 67 | Tie |
| TTFB | 439ms | 477ms | core-js |
| Composite | 74 | 74 | Tie |
core-js and Underscore.js are closely matched, each leading in different categories. core-js has a composite score of 74 while Underscore.js scores 74.
Choose core-js when your primary concern is server response time. Its audit data shows consistent strength in these areas across the sampled sites.
Choose Underscore.js when your primary concern is performance. Its audit data shows consistent strength in these areas across the sampled sites.
Scores are medians across 1840 audited core-js sites and 218 audited Underscore.js 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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