Whether an email reaches the inbox is decided in a fraction of a second by the receiving provider — Gmail, Outlook, Yahoo. They look at who you are, how you send and how people react. This guide walks through each, in the order that matters.
How providers decide
| Signal | What they ask | What you control |
|---|---|---|
| Authentication | Is this really from the domain it claims? | SPF, DKIM and DMARC records |
| Reputation | Has this domain and server behaved well before? | Steady volumes, low bounces and complaints |
| Engagement | Do people open, reply and keep these emails? | Sending to people who asked, and only them |
| Content | Does it look like what people expect from you? | Honest subjects, a clear sender, an easy exit |
Content gets the most attention online, but it matters least. Authentication and reputation come first.
Authenticate your domain
SPF — who may send
A TXT record on your domain listing the servers allowed to send for it. Keep one SPF record only, and end it with ~all or -all — never +all.
v=spf1 include:_spf.google.com include:spf.your-host.com ~allDKIM — a signature on every email
Your mail provider signs each message with a private key; the public key sits in DNS under a “selector”, such as default._domainkey. Turn it on in your provider’s settings and publish the record they give you.
DMARC — the policy that ties them together
DMARC tells providers what to do when SPF and DKIM fail, and sends you reports. Start gently and tighten once everything passes:
v=DMARC1; p=none; rua=mailto:[email protected]— watch the reports.p=quarantine— failing mail goes to spam.p=reject— failing mail is refused. Full protection against spoofing.
Devlo reads all of this live from DNS in Settings›Email Sending → Domain Health, with a corrected record to copy when something is wrong — and holds a campaign if SPF, DKIM or DMARC is broken.
Choose how you send
- Your own mailbox (Gmail, Microsoft 365, Zoho, cPanel) — simple and personal, but with daily and hourly limits. Good for small lists.
- An email-sending service (Amazon SES, Mailgun, Brevo) — built for volume, with its own SMTP login. Good for larger lists.
- A subdomain for campaigns, such as
news.yourdomain.com, keeps campaign reputation apart from your day-to-day email.
Whichever you choose, send campaigns from an address on your own domain. Bulk email from a free @gmail.com address fails DMARC at most providers.
Build a list on permission
- Collect addresses where people sign up knowingly — your website, your shop, an event.
- Say what they will receive and how often.
- Consider double opt-in: a confirmation email before they are added.
- Never buy, rent or scrape a list. Our Anti-Spam Policy forbids it, and so does the law in most countries.
Keep the list clean
A clean list protects your reputation more than anything else you can do.
- Remove hard bounces immediately — Devlo stops sending to them automatically.
- Honour unsubscribes at once and forever.
- Catch typos and broken addresses on import.
- Every few months, ask quiet contacts if they still want your email, and let go of those who do not answer — Campaigns›Re-engagement does this with tiers and a sunset policy.
Write emails that belong in the inbox
- A sender name people recognise, and a reply-to that reaches a person.
- A subject that matches the content. No false “Re:”.
- A sensible balance of text and images; not one big image.
- Links to your own domain, not long chains of redirects or shorteners.
- A visible unsubscribe link — Devlo adds it, plus the one-click unsubscribe header.
Pace your sending
Sudden spikes look like spam. Keep volumes steady, and grow slowly when you start — see the 14-day ramp-up plan. In Devlo, batch size, delay and a maximum per hour per domain keep every campaign at a human pace.
Monitor what matters
| What | Healthy | Where to see it |
|---|---|---|
| Spam complaints | below 0.1% (Google’s limit is 0.3%) | Google Postmaster Tools, Yahoo Sender Hub |
| Hard bounces | below 2% | Devlo → Bounced |
| Blocklists | not listed | Devlo → Domain Health |
| DMARC reports | all your mail passes | The address in your DMARC record |
| Opens and clicks | steady or rising | Devlo → Campaign History |
When things go wrong
Stop adding volume while you investigate.
Re-run Domain Health. A changed host or a new tool often breaks SPF or DKIM.
Where did the recent contacts come from? Remove anything without clear permission.
If listed, fix the cause first, then request removal on the list’s own page.
Send to your most engaged contacts first, and grow back gradually.
The one-page checklist
- SPF, DKIM and DMARC published and passing.
- Campaigns from your own domain.
- Only people who asked to hear from you.
- Unsubscribe link and one-click header in every email.
- Bounces and unsubscribes removed automatically.
- Quiet contacts re-engaged or let go.
- Steady, paced volumes.
- Complaints under 0.1%, bounces under 2%.
Check your domain in a minute
Devlo reads your SPF, DKIM, DMARC and 9 blocklists for you. Start free.