Glossary Entry
What is DKIM?
DKIM without the jargon — the definition, the analogy, and why any site owner should care.
The short answer
DKIM puts a cryptographic signature on outgoing mail, letting receivers confirm it came from your domain and arrived unedited.
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
0
Jargon left undefined
100+
Entries, all cross-linked
Real
Working examples
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To read, always
Your mail server signs each message with a private key, and the matching public key sits in DNS under a selector for receivers to fetch and check against. Unlike SPF, the signature travels inside the message, which means it survives being forwarded.
Every service sending on your behalf signs under its own selector, so several keys coexist without conflict. Each of hosting mail, the newsletter tool and the CRM can be verified on its own.
The everyday parallel
Every letter carries a wax seal, checked against the impression you published. An intact seal proves the sender and proves nobody opened it, however many hands passed it along.
Any analogy flattens the detail, naturally — but this one is solid enough to think with, and thinking is what a jargon buster is for.
What genuinely rides on it
Your sending reputation is built through DKIM, and DMARC cannot be enforced without it. Leave it out and you see the result as mail landing in spam. Putting it in place is generally one click in the panel and one DNS record.
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.
One worked example
Forward an invoice from one address to another and it still verifies at the far end. That forwarding hop broke SPF's check against the sending server, and the DKIM seal inside the message came through it intact.
Scale that example across every website online and you have described the whole job of the concept in one stroke.
How Hosting & Domains deals with it
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 SPF, DMARC, TXT Record and SMTP.
The rate you register at is the rate you renew at, so year two costs precisely what year one did — nothing lying in wait on the invoice.
Unexplained jargon slows everybody down
An unexplained piece of jargon is, to us, a service defect. This is the support team's collected translations, published where a search engine can hand them over on our behalf.
A copy is taken daily on every plan, and putting a file or a database back is one click in the panel rather than a support ticket.
- 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
Jargon-free by design
Definitions written for people who run sites, not for other sysadmins — translation rather than restatement.
This term, properly landed
DKIM defined, pictured by analogy and located in your own panel — recognise-level after a single read.
The next step, drawn out
Carry on into SPF and DMARC — ideas rarely travel alone, so the neighbours are linked in.
Analogies that hold
Every concept comes with a mental model that returns exactly when you need it.
Tied to real hosting
Examples name platforms you would genuinely use, never an abstract diagram on a whiteboard.
Cross-wired entries
Related terms point at each other, so one lookup compounds into working knowledge.
Quick Start
Order placed to site online
- 1
Find it in your own account
Nothing teaches a hosting term faster than finding it in your own panel; five minutes of looking beats an hour of reading.
- 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 — SPF, DMARC and TXT Record finish this one's picture, each a two-minute read away.
Built In
Fitted to every plan
- Staging copies for trying a change before it goes live
- No set-up charge at any point, and no joining fee
- WebP image optimisation built in, at no extra charge
- cPanel, which is what most of the industry already runs
- SSH, Git and Composer on the developer plans
- Softaculous included for one-click application installs
- People on the support desk every hour of every day
- A renewal figure identical to the one you registered at
- DDoS filtering absorbed at the network edge
- A daily copy, with restores you run yourself from the panel
Frequently Asked
The questions that come up most
Do I need SPF and DKIM both?
Both, because they fail in different circumstances. SPF breaks on forwarding, DKIM can break when a mailing list rewrites the body, and DMARC passes as long as one of them aligns. The pair plus DMARC is what receivers now expect.
What is a DKIM selector?
It is the label telling a receiver where to find a particular key, published at selector._domainkey.yourdomain. Since each signing service chooses its own selector, one domain can carry several keys at once. Both the panel and every platform sending on your behalf tell you exactly which record to create.
Can I transfer in a name I already own?
Yes, and it is routine. Unlock the name at your current registrar, take the auth code, and start the transfer from your client area. Whatever registration time remains carries over, and DNS keeps resolving the whole way through.
Will you move my existing site free of charge?
Yes. Open a ticket with the login for your current host and we bring the lot across — files, databases, mailboxes, configuration. You check the copy before DNS moves, and the old site keeps taking traffic right up to the moment the new one serves it, so nobody meets a gap.
Keep reading
SPF (Sender Policy Framework)
SPF is a DNS record naming the mail servers allowed to send for your domain, which gives receivers a way to…
DMARC
DMARC is the policy layer above SPF and DKIM, telling receivers how to treat mail that fails those checks a…
How to Set Up DKIM Signing
The way it is really done, in order, with the usual mistake pointed out.
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