Documentation

Email deliverability

How Bulk Mail keeps your emails out of the spam folder — and the three DNS records you set up once on your sending domain.

Whether an email reaches the inbox depends on two things: reputation — how you send — and authentication — proof that you are who you say you are. Bulk Mail takes care of the first automatically. The second is a one-time DNS setup on your domain, described below.

How Bulk Mail protects your deliverability

Your own mailbox	Campaigns go out through your own email account and domain — not a shared sending pool — so your results depend on your own sending, never on other customers'.
Gradual warm-up	Each mailbox starts at 15 emails a day and adds 5 per day up to its daily limit, building trust with mail providers the way they expect.
Human pacing	Emails go out in small batches with random pauses, spread through your sending window on business days — like a person working through a list, not a blast.
One-click unsubscribe	Every campaign email carries the `List-Unsubscribe` and `List-Unsubscribe-Post` headers that Gmail, Yahoo and Outlook expect from bulk senders, plus an unsubscribe link in the footer.
Well-formed messages	Plain-text and HTML versions of every email, a proper Message-ID and date, and your Reply-To — the signals spam filters look for in legitimate mail.
Automatic suppression	Hard bounces and unsubscribes are never emailed again, and are filtered out of every list you upload.
Follow-ups that listen	A follow-up is cancelled as soon as someone replies (out-of-office replies excepted), so nobody is chased after answering.
Sensible list sizes	Audience size limits per plan (3,000 on Regular, 25,000 on Pro) keep volume in proportion to a mailbox's reputation.
Health monitoring	Your bounce and unsubscribe rates are tracked continuously and you're alerted if they become risky — see below.

Deliverability health

Bulk Mail calculates your bounce and unsubscribe rates over the last 30 days and shows a status on your dashboard once you have sent enough email for the numbers to be meaningful (around 500 emails):

Rate	Green	Yellow	Red
Hard bounces	below 4%	4–5%	5% or more
Unsubscribes	below 1.6%	1.6–2%	2% or more

If your status gets worse you receive an alert email with the numbers. Bulk Mail doesn't stop your sending on its own — you decide what to do. On yellow or red: pause the campaign, remove or verify old addresses, and check your DNS records below.

List hygiene

Keep bounces under 2%. Mail providers start to distrust senders above that. Purchased and registry lists often contain dead addresses — run them through an email verification service before uploading.
Start small. Send to your best-quality contacts first while the mailbox warms up.
Write like a person. Personal greeting, short text, one or two links, no attachments, no image-only emails.
Make it easy to say no. A Not interested one-click button costs nothing and prevents spam complaints from people who would otherwise press “Report spam”.

Set up SPF, DKIM and DMARC

When you send through your own SMTP mailbox, Gmail, Outlook, Apple Mail and every other major provider check three DNS records on your sending domain to decide whether a message is legitimate. Without them — or with them set up incorrectly — your emails are very likely to land in spam, or be rejected outright.

SPF	Names the mail servers authorized to send on behalf of your domain.
DKIM	Cryptographically signs each message so receivers can verify it was not tampered with in transit.
DMARC	Tells receivers what to do when SPF or DKIM fail — report, quarantine or reject.

The mailbox setup wizard checks all three for your domain and tells you exactly what is missing.

SPF — Sender Policy Framework

SPF is a single TXT record on your sending domain. It authorizes your email provider's servers to send messages from your domain.

Provider	SPF record (TXT on yourdomain.com)
Hostinger	`v=spf1 include:_spf.mail.hostinger.com ~all`
Google Workspace	`v=spf1 include:_spf.google.com ~all`
Microsoft 365	`v=spf1 include:spf.protection.outlook.com ~all`

Only one SPF record per domain. If you already have one, merge the new include: into it rather than adding a second record.

DKIM — DomainKeys Identified Mail

DKIM publishes a public key in DNS so recipients can verify each message was signed by your mail server. Enable DKIM at your email provider, then add the CNAME or TXT record they generate to your DNS.

Hostinger: Hosting panel → Emails → DKIM → Enable. Selector: hostingermail1
Google Workspace: Admin console → Apps → Google Workspace → Gmail → Authenticate email → Generate new record
Microsoft 365: Microsoft 365 Defender → Email & collaboration → Policies → DKIM → Enable
Other providers: search the provider's documentation for “DKIM setup” — it gives you the exact records to publish.

DMARC — Domain-based Message Authentication

DMARC ties SPF and DKIM together and tells receivers what to do with messages that fail authentication. It is a TXT record named _dmarc.yourdomain.com. Always start in monitoring mode and tighten gradually as you confirm legitimate mail is passing.

Phase	Record	Effect
1. Monitoring (start here)	`v=DMARC1; p=none; rua=mailto:[email protected]`	Run for 2–4 weeks. Nothing is blocked; reports arrive at the `rua` address.
2. Partial enforcement	`v=DMARC1; p=quarantine; pct=25; rua=mailto:[email protected]`	25% of failing mail goes to spam. Raise `pct` to 50, then 100.
3. Full enforcement (target)	`v=DMARC1; p=reject; rua=mailto:[email protected]`	Failing mail is rejected — the strongest protection against spoofing of your domain.

Check your records are live

DNS changes can take 1 to 24 hours to propagate. Confirm your records are visible before launching a campaign:

MXToolbox	SPF, DKIM, DMARC and MX lookups in one place.
dnschecker.org	Checks propagation across 30+ servers worldwide.
mail-tester.com	Send a test email and get a 1–10 deliverability score with detailed feedback.

Common issues

Multiple SPF records

Only one TXT record starting with v=spf1 is allowed per domain. If you see more than one, merge their include: parts into a single record.

DKIM not propagated yet

DNS changes can take up to 24 hours worldwide. Use dnschecker.org to confirm the record is visible from several regions before sending.

DMARC too strict too soon

Stay on p=none for at least 2–4 weeks. Only move to p=quarantine or p=reject after reviewing the reports and confirming legitimate mail passes.

From address on a different domain

The domain in your From address must be the one with the SPF, DKIM and DMARC records. Sending from [email protected] requires the records on example.com.

Campaign seems to have stopped

Usually today's warm-up limit is reached or the sending window has closed; sending continues automatically in the next window. See Mailboxes & sending limits.