Why deliverability is the first thing we audit
You can write the best campaign of your life and still lose the revenue if it lands in spam. Before we touch copy or design for a new client, we run the same twelve checks. Work through them in order — the early ones are worth more than the later ones.
1. Authenticate properly (SPF, DKIM, DMARC)
Google and Yahoo now require bulk senders to authenticate. You need a valid SPF record, DKIM signing on your sending domain, and a DMARC policy published at _dmarc.yourdomain.com. Start at p=none so you can read the reports, then move to p=quarantine once your legitimate sources are all passing.
2. Send from a subdomain
Use something like mail.yourdomain.com for marketing. It keeps your corporate email reputation separate from your campaign reputation, so a bad send never stops your sales team's replies arriving.
3. Warm up new domains and IPs
A brand new sending domain that suddenly pushes 50,000 emails looks exactly like a spammer. Ramp over three to four weeks, starting with your most engaged contacts and doubling volume every couple of days.
4. Clean the list before you send
Remove hard bounces immediately, suppress anyone who has not opened in 12 months, and run a validation pass on any list you have not mailed in six months. Spam traps live in old data.
5. Stop mailing unengaged contacts
Mailbox providers score you on engagement. Sending to people who never open drags down inbox placement for the people who do. Segment by recency and mail your 0-90 day segment most often.
6. Set up a real re-engagement flow
Before you suppress a contact, give them one last honest sequence: what they signed up for, what they will get, and an easy way to leave. A shrinking, engaged list outperforms a large dead one every time.
7. Make unsubscribing easy
One-click list-unsubscribe headers are now expected. Hiding the link pushes people to hit "report spam" instead, which is far more damaging than an unsubscribe.
8. Watch your complaint rate
Keep spam complaints under 0.1%. Above 0.3% and you will see placement collapse. Google Postmaster Tools shows this for Gmail; check it weekly.
9. Fix the content signals
Avoid image-only emails, keep a healthy text-to-image ratio, use a real reply-to address, and never use link shorteners or a redirect domain with a poor reputation.
10. Align the from-name with expectations
If people signed up on a brand site, send as that brand. Sudden changes in from-name look like a hijacked list to both filters and humans.
11. Monitor blocklists
Check your sending IP and domain against the major blocklists monthly. Most listings are recoverable if you fix the cause and request delisting quickly.
12. Test placement before every major campaign
A seed-list placement test takes ten minutes and tells you whether your biggest send of the quarter is heading for the Promotions tab, the spam folder, or the inbox.
Where most UK teams get stuck
Steps 1-4 are technical and usually get done. Steps 5-8 are ongoing habits, and that is where programmes drift. If your open rates have slid over the last two quarters without an obvious cause, it is almost always engagement-based filtering rather than a sudden block.
If you want a second pair of eyes on this, our email deliverability consultants run a full audit and hand you a prioritised fix list.