From the NordicCDN blog
Performance, caching, security and the craft of running a fast website or webshop.
Why your images belong on a CDN (and what an image CDN adds)
Images are usually the heaviest thing you ship and the easiest big win you are not taking. What a CDN fixes, and the four things an image CDN does that a plain one does not.
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ESI explained: cache the page, personalize the bits
The classic caching dilemma: the page is 99% identical for everyone, but that 1% — the username, the cart count — makes the whole thing uncacheable. ESI is one of two ways out, and it is not always the right one.
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Cart abandonment and speed: the link nobody talks about
There is a whole industry of advice about cart abandonment — emails, popups, discount codes. Almost none of it mentions the cause that quietly makes every other cause worse.
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TTFB: what a good time to first byte looks like, and how to get there
Time to First Byte is the wait before your server says anything at all, and it sets the ceiling for everything after it. What good looks like, and how to find which part of yours is slow.
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WebP vs AVIF: which image format should you actually use?
Images are usually the heaviest thing on your page, so the format matters. AVIF squeezes smaller, WebP is everywhere — but the decision most sites should be making is a different one entirely.
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Cache hit ratio: what it is and how to get yours above 95%
It is the one number that tells you whether your CDN is actually doing its job. What it means, the five things that usually wreck it, and how to work out which one is wrecking yours.
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Brotli vs Gzip: which one should your server use?
Both shrink your text before it hits the wire, and both are basically free speed. The honest comparison — which compresses harder, which is faster, and why the answer depends on whether the file is cacheable.
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Core Web Vitals in 2026: LCP, INP and CLS without the jargon
Three acronyms decide a chunk of how Google ranks you and how your site feels to use. Here is what LCP, INP and CLS really measure — and, for each, the change that moves the number most.
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What is a CDN, and do you actually need one?
CDN gets thrown around like everyone already knows what it means. Here is the plain-English version — what it does, how it works, and an honest answer to whether your site needs one.
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