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core-js vs Optimizely

Based on 2041 and 126 real audits

View core-js details | View Optimizely details
Metriccore-jsOptimizelyWinner
Performance3731core-js
Accessibility8890Optimizely
Best Practices8687Optimizely
SEO9191Tie
Security6865core-js
TTFB483ms185msOptimizely
Composite7472core-js
Performance
core-js
37
Optimizely
31
Accessibility
core-js
88
Optimizely
90
Security
core-js
68
Optimizely
65
SEO
core-js
91
Optimizely
91
Composite
core-js
74
Optimizely
72

core-js and Optimizely are closely matched, each leading in different categories. core-js has a composite score of 74 while Optimizely scores 72.

When to choose core-js

Choose core-js when your primary concern is performance and security. Its audit data shows consistent strength in these areas across the sampled sites.

When to choose Optimizely

Choose Optimizely when your primary concern is server response time and accessibility. Its audit data shows consistent strength in these areas across the sampled sites.

How this comparison was built

Scores are medians across 2041 audited core-js sites and 126 audited Optimizely 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 →

FAQ

Which is faster, core-js or Optimizely?
Based on real BeaverCheck audits, core-js sites score higher on Lighthouse performance (37 vs 31 on average).
Which has better security, core-js or Optimizely?
core-js sites score higher on security analysis (68 vs 65 on average).
Which has better accessibility, core-js or Optimizely?
Accessibility scores measured by Lighthouse WCAG 2.1 checks favor Optimizely (90 vs 88). Both technologies can be made fully accessible with care — the difference reflects common patterns in the sampled sites, not inherent platform limits.
Which is better for SEO, core-js or Optimizely?
core-js sites score higher on Lighthouse SEO signals (91 vs 91 on average), which cover meta tags, crawlability, mobile friendliness, and structured data. Content strategy and backlinks still matter more than platform choice for ranking.
Which has faster server response (TTFB), core-js or Optimizely?
Optimizely sites show lower Time to First Byte (185 ms vs 483 ms on average). TTFB depends heavily on hosting and CDN setup rather than the technology itself, but the sampled sites suggest a meaningful difference in common deployment patterns.
Should I choose core-js or Optimizely for my website?
Both platforms have trade-offs. core-js scores higher on overall composite score while core-js may excel in metrics you care about most. Run a free BeaverCheck audit on a real site using each to compare the metrics relevant to your use case.
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