How to improve your email deliverability
A simple guide to getting your marketing emails into the inbox, not the spam folder.
Delivery vs deliverability: what's the difference?
These two terms get mixed up a lot, but they're not the same thing.
Email delivery is about whether an email reaches your recipient's mail server at all. If it doesn't bounce, it's been delivered. Bounces happen for all sorts of reasons - a misspelled address, a server that's temporarily down, and so on.
Email deliverability is the next step: whether your email actually lands in the inbox, or gets filtered into spam. This is where things get trickier for bulk sends. A one-to-one email to a colleague will almost always land safely. A marketing email sent to your whole database is a different story, because email providers treat bulk sends with more suspicion — not because your platform has technical issues, but because bulk email can look like spam.
Every provider runs its own spam filters, using its own criteria, and those criteria change over time. It's not an exact science, so even good, legitimate emails can occasionally get caught out. You can't guarantee perfect deliverability, but you can stack the odds in your favour.
Five ways to improve your deliverability
1. Keep your database clean and consenting
Only email contacts who've explicitly opted in to hear from you. Don't repurpose an old list from a different venue or campaign - permission doesn't transfer.
2. Send content people actually want
The more relevant and useful your emails are, the more engaged your audience stays — and the less likely they are to hit "report spam." Engagement is one of the biggest signals providers use to judge you.
3. Steer clear of spam triggers
A few things that raise red flags with spam filters:
- Excessive symbols in your subject line (!!!, $$$, ???)
- ALL CAPS or classic spam trigger words
- A heavy image-to-text ratio
- URL shorteners
- Oversized images
Keep your emails short, well-balanced, and clean.
4. Watch your engagement metrics
Track your open and click rates, and review them regularly. They'll tell you:
- The best times to send
- Which content performs best
- Which subject lines aren't landing
- Whether you're sending too often
5. Don't send from a free email address
Sending from a Gmail, Hotmail, or similar address puts you under stricter authentication checks — and makes you more likely to be flagged. Use a proper domain-based sender address instead.
The bottom line
The fundamentals of good deliverability come down to one thing: send wanted emails, to people who asked for them, with content they'll actually value. Get that right, and the rest follows.