Domain reputation and deliverability: how to land in the inbox

Deliverability decides whether your emails reach the inbox or land in spam, and it is governed by your domain reputation: the receiving servers' combined judgment of how your domain has behaved historically. Three things build that reputation: correct technical authentication, controlled volume and recipients who actually reply instead of deleting.

What are SPF, DKIM and DMARC?

The three acronyms are the baseline requirement. Without them, Google and Microsoft sort you out before the content is even judged.

• SPF is a public list of which servers are allowed to send mail for your domain. If someone else sends in your name, the check fails.
• DKIM is a cryptographic signature on every email that proves it was not changed in transit and that it really comes from you.
• DMARC is your policy for what the recipient should do when SPF or DKIM does not match: let it through, quarantine it or reject it.

All three are set up as DNS records and take a technician under an hour. Since 2024, Google and Yahoo require them in practice for anyone sending outgoing volume. Verify with a free test tool before you send anything at all.

Why is warmup needed?

A new domain or email address has no reputation. If it suddenly sends 200 emails a day, it looks exactly like a spammer who just registered a domain, and the receiving servers act accordingly.

Warmup means building the volume up gradually:

1. Start with a handful of emails per day to addresses that reply
2. Increase slowly over four to six weeks
3. Then hold at a cap, typically 20 to 40 outreach emails per address per day

The replies are what matter. A domain that gets replies builds reputation faster than one that only sends.

How do you handle bounces?

Every email to an address that does not exist, a hard bounce, is a signal to the receiving server that you do not maintain your list. According to Apollo, 22.5 percent of contact data decays per year, so a list that has sat untouched for three years can contain more than half dead addresses.

Rules to follow:

• Verify all addresses before sending, especially old CRM lists
• Keep the bounce rate under 2 percent. Over 5 percent is an emergency
• Remove hard bounces immediately, they never become valid again
• Pause on soft bounces and try later, but at most a couple of times

Why do mass sends burn the domain?

A generic email to 2,000 contacts at once creates everything that damages reputation at the same time: a volume spike, a low reply rate, high deletion rates and a few spam complaints. Spam complaints weigh heaviest of all. Around 0.3 percent complaints already starts Google acting against the whole domain, not just the campaign.

That is why personal, researched emails in low volume do not just convert better. They are also the only way to send sustainably without ruining the domain for the whole company, including your ordinary customer emails and invoices.

Subdomain or main domain?

The rule of thumb depends on who you are writing to:

• Cold volume to unknown recipients: use a separate domain or subdomain, so the main domain is protected if something goes wrong.
• Low volume to contacts who know you, for example reactivation of your own B2B leads: the main domain is often justified, because the sender should be recognized and the volume is controlled.

Whatever you choose: never mix outreach and transactional email on the same address.

Why measure replies instead of opens?

Open data is unreliable since Apple Mail began preloading all email, which registers opens that never happened. Tracking pixels can also hurt deliverability in themselves. Reply rate is the only metric that is both true and builds your reputation. A send with 40 percent opens and zero replies is a failure. Five replies to fifty emails is a working system.

That is also how Leo, Revexa's AI, is built: low volume, personal emails from your own domain and replies as the only yardstick. Run the numbers on your own list in the calculator on the home page.

Common questions

How long does it take to repair a burned domain reputation?

Count on one to three months of low volume and high quality. In severe cases it is faster to start over on a new subdomain with correct setup.

Is SPF, DKIM and DMARC enough to reach the inbox?

No. Authentication is the ticket into the judging, not a passing grade. Volume, list hygiene and recipient behavior decide the rest.

How many emails per day are safe?

For outreach: 20 to 40 per address per day after warmup is complete. If you need more volume, scale with more addresses, not a higher cap.