You write a newsletter, press send, and half your customers never see it. It went to spam, or it was blocked. Email deliverability is the work of making sure your emails reach the inbox, and for businesses sending bulk email it starts with three acronyms: SPF, DKIM, and DMARC. This guide explains them in plain language.
Why emails go to spam
Email providers such as Gmail and Yahoo protect their users from spam, so they judge every message on:
- Who is sending it: is the sender really who they claim to be?
- How the sending domain is set up: are the right security records in place?
- How recipients react: do people open it, or mark it as spam or delete it unread?
- The list quality: how many addresses are wrong, old, or never agreed to receive it?
- The content: does it look like a normal business message, or like spam?
No provider can guarantee inbox placement, but you can improve your chances a lot.
SPF: who is allowed to send
SPF (Sender Policy Framework) is a record in your domain's DNS that lists the servers allowed to send email for your domain. When a message arrives, the receiving server checks whether the sending server is on the list. If it is not, the message looks suspicious.
DKIM: proof the email is genuine
DKIM (DomainKeys Identified Mail) adds a digital signature to every email you send. The receiving server checks that signature against a public key in your DNS. If it matches, it proves the message really came from your domain and was not changed on the way.
DMARC: what to do when checks fail
DMARC ties SPF and DKIM together. It tells receiving servers what to do with messages that fail the checks (nothing, send to spam, or reject), and it sends you reports about who is sending email using your domain. A common approach is to start by monitoring only, then move to stricter policies once your legitimate email is passing consistently.
Large mailbox providers such as Gmail and Yahoo now expect bulk senders to authenticate their email and to make unsubscribing easy, so setting these records up is no longer optional for businesses that send newsletters or promotions.
Build a clean list
- Only email people who agreed to hear from you. Never buy or scrape lists.
- Remove bounced addresses and people who have not engaged for a long time.
- Include a clear unsubscribe link in every marketing email, and honour requests quickly.
- Collect addresses properly, for example through a sign-up form or at checkout with clear consent.
Send well
- Send from your own business domain, not a free webmail address.
- Keep marketing and order emails separate, so a promotional campaign never delays an order confirmation.
- Increase volume gradually when you start sending from a new setup, rather than sending a large campaign on day one.
- Write for people: a clear subject line, useful content, and a good balance of text and images. Avoid all-capital subject lines and misleading claims.
- Watch the results: bounces, unsubscribes, and spam complaints tell you when something is wrong.
Transactional vs marketing email
Order confirmations, invoices, and password resets are transactional emails that a customer expects. Newsletters and offers are marketing emails. They have different rules, and many businesses send them from different servers or addresses so the important order emails are protected.
Frequently asked questions
Why do my emails go to spam even though I did everything right?
It can come from several things together: missing SPF, DKIM, or DMARC records, a list with old or unengaged addresses, or content that looks like spam. Fix the setup first, then clean the list.
How long does it take to build a good sending reputation?
It usually takes weeks of steady, consistent sending to people who engage with your emails. Reputation is built over time.
Do I need a dedicated mail server?
Not always. It depends on how many emails you send and how much control you need. We can recommend a setup after hearing about your volume.
Get your bulk email set up properly
We provide bulk SMTP mail servers and help set up your sending domain correctly. See our bulk email servers, our bulk SMS service, or contact us.