Glossary Entry
What is CDN?
CDN without the jargon — the definition, the analogy, and why any site owner should care.
The short answer
A CDN mirrors your site's assets across servers in many countries, so each visitor collects them from whichever is nearest instead of from your origin.
What follows: the longer explanation, a picture that holds, the practical stakes, and the places you will genuinely meet it.
By the Hosting & Domains team · Reviewed 18 August 2026
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Jargon left undefined
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To read, always
Distance costs milliseconds. Move an edge node a continent closer and the round trip shortens for images, scripts, stylesheets and sometimes whole pages. Most CDN providers bundle security in with delivery, adding a WAF and absorbing traffic floods.
The value depends on where your audience is. Readers spread around the world gain a great deal, while one country's audience on hosting already sited near them gains much less. Measure before committing.
The everyday parallel
A mail-order firm running regional depots. Every order ships from the depot nearest its customer rather than from a single warehouse at the far end of the country, and head office handles only what the depots cannot supply.
Any analogy flattens the detail, naturally — but this one is solid enough to think with, and thinking is what a jargon buster is for.
Where it touches your own site
Where the audience is scattered, nothing after caching itself moves latency as much as a CDN. From day one it also joins the purge routine, since an out-of-date copy at the edge is one more place your edit has failed to arrive.
Nobody expects you to work at this layer daily. The aim is recognising it when it explains something — and that moment is exactly when this page pays for itself.
How it turns up day to day
Readers of a tutorial site are everywhere, and its images come off local edges. Somebody in Sydney takes their assets from Sydney rather than waiting for a round trip to a European origin.
Scale that example across every website online and you have described the whole job of the concept in one stroke.
Where it appears on this platform
You will meet it in the control panel and now and then in a support thread, usually already set correctly. If this one landed, the natural follow-ups are Cache, DDoS Attack, Bandwidth and Nginx.
Mailboxes at your own name are part of the plan — mail is included, not sold back to you at the checkout.
Unexplained jargon slows everybody down
Sooner or later every confusing hosting term turns into a support ticket, so we defined the hundred commonest ones properly — once, in the same plain English we use with customers.
A free SSL certificate comes with every plan and reissues itself before the old one lapses — the padlock is never yours to diarise.
- 100+ entries, plain English all the way
- Ordinary analogies, working examples
- Neighbouring ideas linked together
- Written by our own support engineers
Why Hosting & Domains
Standard on every plan
Tied to real hosting
Examples name platforms you would genuinely use, never an abstract diagram on a whiteboard.
This term, properly landed
CDN defined, pictured by analogy and located in your own panel — recognise-level after a single read.
The next step, drawn out
Carry on into Cache and DDoS Attack — ideas rarely travel alone, so the neighbours are linked in.
Stakes made explicit
More than what a thing is: the moments it turns out to be the answer to a problem you have.
Clear about how deep to go
Most of these are recognise-level rather than operate-level, and every entry says which it is.
Analogies that hold
Every concept comes with a mental model that returns exactly when you need it.
Quick Start
Order placed to site online
- 1
Find it in your own account
Open the control panel and find where this idea sits — a definition turns into understanding the moment it attaches to your own site.
- 2
Check the defaults as they stand
Look at how your account has it configured. Nine times in ten the default is right, and a check turns the guess into certainty.
- 3
Chase the neighbouring terms
Hosting terms travel in groups — Cache, DDoS Attack and Bandwidth finish this one's picture, each a two-minute read away.
Built In
Fitted to every plan
- Webmail in the browser plus IMAP, POP and SMTP for any client
- SSH, Git and Composer on the developer plans
- Your existing site brought across by our engineers, at no charge
- Upgrades applied in place, with no migration when you change plan
- The name's first year included when you order annually
- No set-up charge at any point, and no joining fee
- DDoS filtering absorbed at the network edge
- A renewal figure identical to the one you registered at
- People on the support desk every hour of every day
- NVMe SSD storage on every tier, not only the dear ones
Frequently Asked
The questions that come up most
Does every website need a CDN?
No. There is very little left to win for a UK readership already on solid European hosting. Take one on when your visitors are geographically spread, when you serve a lot of heavy static files, or when you want the bundled security features. Leave it alone where the numbers say your latency is short already.
CDN first, or better hosting first?
Fix the hosting and the caching first, always. A CDN speeds up the delivery of whatever the origin hands over; it cannot make a sluggish origin think faster. Get the origin quick, then put a CDN in front of it, and the gains multiply.
What is the uptime commitment, and what happens in a month that misses it?
99.9% — and if a month falls below that through a fault on our side, our terms entitle you to a pro-rated credit; ask and we apply it. Calling it a target rather than a contractual SLA is a deliberate choice. Hardware and network faults surface through platform monitoring, usually before the first customer notices.
Does hosting include mail?
Yes — every hosting plan includes mailboxes at your own name, with webmail, IMAP, POP and SMTP plus spam filtering on from the start. There is standalone email hosting too, for a name whose website lives somewhere else.
Keep reading
Cache
A cache keeps hold of work already done, returning finished pages, query results and assets straight from m…
Bandwidth
Bandwidth in hosting is the total volume of data your site sends out over a billing month, with every page,…
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