How to improve email deliverability
Deliverability is the share of your email that actually reaches the inbox, not the spam folder and not a silent drop. For transactional email it is critical: a receipt or a password reset that never arrives is a support ticket, or a lost customer. Here is a practical checklist, roughly in the order that matters most.
1. Authenticate your domain
Nothing else helps until this is done. Set up SPF, DKIM and DMARC so mailbox providers can verify your mail is really from you. If you only do one thing, do this. See our guide on SPF, DKIM and DMARC.
2. Send from a domain you control
Send from your own verified domain, not a shared or free-mail address. noreply@yourapp.com on a domain with DKIM and DMARC builds reputation that belongs to you. A From address on a domain you have not authenticated has none.
3. Separate transactional from marketing
Keep password resets and receipts on a different sending stream, and ideally a different subdomain, from newsletters and promotions. Marketing mail attracts more complaints and unsubscribes; you do not want that reputation dragging down the email your users are waiting for. This is what message streams are for.
4. Keep your list clean
Every hard bounce and spam complaint hurts your reputation. Stop sending to addresses that bounce, honour unsubscribes immediately, and never buy or scrape lists. A good provider maintains a suppression list automatically, so a hard-bounced or complained address is never emailed again without you having to track it.
5. Warm up new sending gradually
A brand-new domain or IP has no reputation. Ramp your volume up over days rather than blasting thousands of messages on day one, so providers see a steady, trusted pattern instead of a sudden spike that looks like spam.
6. Write mail that people want
Content still matters. Set a clear, honest subject line, keep a sensible text-to-image and text-to-link ratio, always include a plain-text part alongside the HTML, and make the From name recognisable. Messages that look like the thing the user just asked for get opened, and opens are a positive signal.
7. Handle bounces and complaints
Process the webhook events your provider sends: hard bounces should suppress the address, and complaints (someone marking your mail as spam) should suppress it and prompt a look at what you sent. Ignoring these is how a small problem becomes a blocked domain.
8. Monitor and iterate
Watch your delivered, bounce and complaint rates over time. A rising bounce or complaint rate is an early warning. Set up DMARC aggregate reports so you can see every source sending as your domain, including ones you did not know about.
The short version
Authenticate, send from your own domain, split transactional from marketing, keep the list clean, warm up gradually, and act on bounces and complaints. Most of this is one-time setup; the rest is a provider doing the tedious parts for you.
Mailhuset handles the deliverability plumbing (DKIM signing, SPF and DMARC, automatic bounce and complaint suppression, and a searchable activity log) so you can focus on the email your product needs to send. Start free.