fastify
Fast and low overhead web framework, for Node.js
15.3M weekly downloads · 141.7 KB gzip · Health 85/100
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Comparison guide
Fastify vs Koa
Side-by-side NPM package comparison
Quick Verdict
Smallest Bundle
Koa
61.8 KB gzipped
Most Popular
Fastify
15.3M weekly downloads
Best Maintained
Fastify
100/100 maintenance score
Highest Quality
Fastify
50/100 quality score
Overall Pick
Fastify
Best all-around based on popularity, size, maintenance & quality
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Choosing between Fastify and Koa? Here's a data-driven comparison based on real npm data — downloads, bundle size, health scores, and more — to help you decide which package fits your project best.
Downloads & Popularity
Fastify leads with 15.3M weekly downloads — roughly 2.0x more. Koa has 7.8M weekly downloads. Higher download counts generally indicate broader community adoption and a larger ecosystem of tutorials, plugins, and support.
Bundle Size
Koa has the smallest gzipped bundle at 61.8 KB. Fastify comes in at 141.7 KB. A smaller bundle size means faster page loads, which improves user experience and Core Web Vitals scores.
Health Score Comparison
Fastify has an overall health score of 85/100 (very good), with strong maintenance, security, popularity scores. Koa has an overall health score of 73/100 (good), with strong security, popularity scores. Health scores are calculated from maintenance activity, code quality, security posture, popularity, and stability metrics.
When to Choose Each
Choose Fastify if you value massive community and ecosystem, actively maintained, strong security track record. Choose Koa if you value large community support, strong security track record.
Our Verdict
Both Fastify and Koa are solid choices for JavaScript development. Fastify has the edge in overall health score (85/100), while each package brings unique strengths to the table. Evaluate them based on your project's priorities — whether that's community size, bundle efficiency, or maintenance activity — and choose the one that aligns best with your requirements.
Frequently Asked Questions
- Is fastify better than koa?
- It depends on your needs. Fastify has a health score of 85/100 while Koa scores 73/100. Fastify has more recorded weekly downloads (15.3M). Consider your specific requirements — bundle size, community support, and feature set — to decide which is the better fit.
- Which has a smaller bundle size, fastify or koa?
- Koa has the smaller gzipped bundle at 61.8 KB. A smaller bundle means faster load times for your users, which can positively impact SEO and user experience.
- How many developers use fastify vs koa?
- Fastify has more recorded weekly downloads (15.3M). Download counts reflect package installations, not unique developers.
- Which is better maintained, fastify or koa?
- Fastify has a maintenance score of 100/100. Fastify scores 100/100 and Koa scores 60/100 on maintenance.
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