From the NordicCDN blog
Performance, caching, security and the craft of running a fast website or webshop.
Proof-of-work challenges: stopping bots without annoying humans
Nobody enjoys clicking traffic lights to prove they are human. Proof-of-work challenges take a different approach: make the work invisible to you and expensive for whoever is sending a million requests.
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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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Surviving a traffic spike: how a waiting room keeps your site alive
Sometimes demand simply exceeds what your site can handle — a product drop, a viral moment, a ticket release. A waiting room is the difference between a queue and a crash.
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GeoDNS vs anycast: two ways to send users to the nearest server
Two technologies promise the same thing — send each visitor to a nearby server — but they decide at different moments, and one of them has quietly got less accurate over the last few years.
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Rate limiting explained: protect your API without blocking real users
Rate limiting stops one bad actor — or one buggy script — from hammering your site into the ground, without slamming the door on everyone else. Choosing the limits is the hard part.
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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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PrestaShop performance: caching a dynamic shop the right way
PrestaShop gives you a serious shop out of the box, and a serious amount of work per page to go with it. How to make it fast without breaking the dynamic bits.
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DNS explained: how a domain name becomes a website
You type a name, a website appears. In between, four separate servers get consulted in under 50 milliseconds. Here is the journey, and why changing a record takes longer than making it.
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DDoS protection basics for small sites and shops
DDoS attacks are not just a problem for banks and game studios — small sites get caught in the blast radius constantly. How they work, and what to actually do when one starts.
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