If your Ghost newsletter is landing in spam or not arriving at all it's almost always one of a small handful of fixable things. The most common by far is broken email authentication, and the single biggest culprit is having more than one SPF record on your domain. Fix that, get DKIM and DMARC right, and understand the two separate email systems Ghost runs, and you've solved 90% of deliverability problems.
Ghost sends two kinds of email
Almost every "my emails aren't working" confusion traces back to this. Ghost has two completely independent email systems, and they're configured separately:
- Bulk email (your newsletters). These go out through Mailgun's API, and only Mailgun. There's no SMTP option and no other provider you can plug in natively. If you send newsletters to members, you need Mailgun connected.
- Transactional email (everything else). Magic-link sign-ins, password resets, member signup confirmations, staff invites. These go through whatever you put in Ghost's
mailconfig. Any SMTP provider works (Gmail, SES, Postmark, Brevo, Resend, Mailgun-over-SMTP, you name it). Mailgun's API can also be configured.
Why does Ghost force Mailgun for bulk? Because sending thousands of newsletter emails over plain SMTP is the fastest way to get your IP blacklisted. Bulk sending needs a real email API with reputation management behind it. Ghost's own docs put it bluntly: basic SMTP for bulk "will result in your IP address being instantly blacklisted."
A newsletter that won't send is a Mailgun problem. A magic-link email that won't send is a mail config problem.
Why your newsletter lands in spam
Assuming your email is actually sending, landing in spam comes down to a few things. The following list is roughly in order of how often we've seen them be the cause of issues:
1. Your email isn't properly authenticated.
Mailbox providers (Gmail, Outlook, Apple) want proof that an email claiming to be from your domain is really from you. That's what SPF, DKIM, and DMARC do. Get them wrong and you're treated as suspicious by default.
Here's the whole authentication abbreviation scramble in plain language:
- SPF says "these servers are allowed to send email for my domain".
- DKIM cryptographically signs each email, so it essentially says "yes, this is a genuine email from this domain".
- DMARC, on the other hand, is a policy. It essentially says "this is what you should do with an email that doesn't pass the above tests".
DKIM is something your email sending provider should tell you. It's a key that needs to match 100% – so just copy the record they provide you with.
DMARC, on the other hand, is something you need to decide on. What do you want to happen with unauthenticated emails? To help you set this up, we have created a DMARC generator for you:
Jannis Fedoruk-Betschki
A practical tip: Send your newsletters from something like mail.example.com or send.example.com, not your root domain.
This isolates your bulk-sending reputation from your main domain (and from your inbound/business email), so a rough patch on newsletters doesn't poison everything else. Your from address can still read you@example.com – the sending domain and the visible from-address are different things.
2. You have more than one SPF record.
I'll let someone with more deliverability scars than me make this point. On our podcast, I sat down with Christine Trac, Magic Pages' very first customer, who now does email deliverability professionally for everyone from solo creators to eight-figure e-commerce brands. Her single most-common finding, even at big companies?
Domains with more than one SPF record.
The rule is simple: a domain may have exactly one SPF record. Not one per sender. One, total. If you use Google Workspace for your business email and Mailgun for your Ghost newsletter, you don't add a second v=spf1 record for Mailgun. You merge Mailgun's include: into your existing SPF record:
# WRONG — two SPF records, silently breaks authentication
v=spf1 include:_spf.google.com ~all
v=spf1 include:mailgun.org ~all
# RIGHT — one record, both senders included
v=spf1 include:_spf.google.com include:mailgun.org ~all
When there are two records, providers don't know which to trust, and SPF effectively fails. As Christine put it: this was the reason some of her clients were having spam problems — businesses doing serious revenue, tripped up by a duplicate DNS line.
And if you want to set up a well-defined SPF record, we also created a DNS record generator for that:
Jannis Fedoruk-Betschki
3. Your sending reputation is low or new.
A brand-new sending domain has no reputation, so providers are cautious until you've built a track record. And if past emails got marked as spam or bounced a lot, that follows you.
4. Low engagement. If people don't open, click, or reply, providers learn your mail isn't wanted and start routing it to spam. Deliverability is mostly a popularity contest.
5. It's not actually spam — it's the Promotions tab. Gmail sorting your newsletter into Promotions is not the same as the spam folder. It's still delivered. Don't burn days "fixing" a problem you don't have.
"Can I use something other than Mailgun?"
This question comes up in the Ghost forum quite frequently, especially since Mailgun doubled its pay-as-you-go (Flex) price from $1 to $2 per 1,000 emails on 1 December 2025. The gist of it:
- For newsletters (bulk): no native alternative. Ghost only speaks the Mailgun API for bulk. You can't drop in SendGrid, Postmark, or SES through Ghost's settings.
- For transactional email: total freedom. Magic links and the rest go through any SMTP provider you like.
- The real "alternatives" are proxies, not swaps. There are open-source and managed tools that impersonate the Mailgun API and route the actual sending to a cheaper backend like Amazon SES. They work, but you're now running and owning extra infrastructure – and the deliverability risk that comes with it.
I'll be candid here: Magic Pages itself ran on Amazon SES for our first ~1.5 years and only fully moved to Mailgun in January 2025. So the backend genuinely is swappable behind the scenes, but doing it well, with authentication, reputation management, and bounce handling, is a real job.
For most people the honest answer is: if Mailgun's price is the problem, look at managed hosting. Mailgun's pricing works better in bulk. At Magic Pages we are probably paying a fraction of what you'd get at Mailgun – and we pass this on.
Frequently asked questions
Why does Ghost require Mailgun for newsletters?
Bulk sending needs a real email API with built-in reputation and deliverability management. Plain SMTP gets blacklisted fast. Ghost chose to support one bulk provider – Mailgun – rather than maintain integrations with many. Transactional email (magic links, etc.) can use any SMTP provider.
Can I use Gmail or another SMTP service to send my Ghost newsletter?
Not for newsletters. Those are bulk email and go through the Mailgun API only. You can use Gmail or any SMTP for transactional email (sign-in links, password resets) via Ghost's mail config. To use a different backend for newsletters you'd need a proxy that mimics the Mailgun API.
Why are my Ghost emails going to the Promotions tab?
The Promotions tab isn't the spam folder. Your email is still delivered. It's Gmail categorising newsletter-style mail. Encouraging readers to reply or drag you to Primary helps, but it's not a deliverability failure.
Is Mailgun getting more expensive?
Yes. Mailgun doubled its pay-as-you-go Flex rate from $1 to $2 per 1,000 emails on 1 December 2025. Above ~18,000 emails a month, a fixed monthly plan is usually cheaper than pay-as-you-go. Managed hosting for Ghost might already pay off below that, depending on the provider.
