What is sender reputation?

It's the trust score mailbox providers assign to your sending domain and IP based on how recipients react to your mail. Strong engagement and low complaints and bounces earn inbox placement; spam complaints, dead addresses, and spam-trap hits push you toward the spam folder or an outright block.

How often should I clean my list?

Regularly. Suppress hard bounces immediately, and periodically remove or move aside subscribers who haven't engaged in a long time. A smaller, engaged list almost always outperforms a larger, stale one, and it can keep you on a cheaper subscriber tier.

What's a sunsubscribe versus a spam complaint?

An unsubscribe is a normal, healthy exit and is far better than a spam complaint, which actively harms your reputation. Make unsubscribing easy and obvious so unhappy recipients opt out instead of hitting 'report spam'.

Do I need to warm up a new domain?

Yes, if you're sending in volume from a new domain or IP. Ramp up gradually, start with your most engaged subscribers and increase volume over days and weeks, so providers see a steady, trustworthy pattern rather than a sudden spike.

Improve your sender reputation

Reviewed by Eran Betzalel, founder · 2026-06-29

Your sender reputation is the trust mailbox providers place in your domain based on how people react to your email, and it is what decides whether you reach the inbox or the spam folder. Boostmail helps you target 95% inbox placement with built-in sender-reputation monitoring and bounce and complaint handling, but the day-to-day habits below are what keep that reputation healthy. The core idea is simple: send wanted mail to engaged people, and stop sending to addresses that bounce or complain.

Keep your list clean

List hygiene is the foundation of good deliverability:

Only mail people who opted in. Never send to purchased or scraped lists. This starts at import, where you should bring in consented contacts only.
Suppress hard bounces immediately. A hard bounce means the address is invalid. Continuing to mail it signals to providers that you don’t maintain your list. Boostmail handles bounces so dead addresses stop receiving mail.
Prune disengaged subscribers. Periodically remove or sideline people who haven’t opened or clicked in a long time. A smaller, engaged list beats a large, stale one, and fewer active subscribers can mean a lower-cost tier.

Earn engagement

Providers watch how recipients interact with your mail. Opens, clicks, and replies are positive signals; deletions without opening and spam complaints are negative ones. To keep engagement high, send relevant content to well-defined segments, maintain a consistent but not overwhelming cadence, and write subject lines that set honest expectations.

Handle complaints and unsubscribes well

A spam complaint hurts far more than an unsubscribe. Make unsubscribing easy and visible so dissatisfied recipients opt out instead of reporting you. Boostmail’s complaint handling helps you act on feedback so repeat issues don’t drag down your reputation.

Warm up new domains and IPs

If you’re sending volume from a new domain, don’t blast your whole list on day one. Warm up by starting with your most engaged subscribers and increasing volume gradually over days and weeks. A steady, growing pattern looks trustworthy; a sudden spike from a cold domain looks like spam. The same applies when ramping up scheduled sends at scale.

Start with authentication

None of this works without the basics in place. If you haven’t already, authenticate your domain with SPF, DKIM, and DMARC first, it’s the prerequisite for everything above. Learn more about Boostmail’s deliverability features.

Frequently asked questions

What is sender reputation?: It's the trust score mailbox providers assign to your sending domain and IP based on how recipients react to your mail. Strong engagement and low complaints and bounces earn inbox placement; spam complaints, dead addresses, and spam-trap hits push you toward the spam folder or an outright block.
How often should I clean my list?: Regularly. Suppress hard bounces immediately, and periodically remove or move aside subscribers who haven't engaged in a long time. A smaller, engaged list almost always outperforms a larger, stale one, and it can keep you on a cheaper subscriber tier.
What's a sunsubscribe versus a spam complaint?: An unsubscribe is a normal, healthy exit and is far better than a spam complaint, which actively harms your reputation. Make unsubscribing easy and obvious so unhappy recipients opt out instead of hitting 'report spam'.
Do I need to warm up a new domain?: Yes, if you're sending in volume from a new domain or IP. Ramp up gradually, start with your most engaged subscribers and increase volume over days and weeks, so providers see a steady, trustworthy pattern rather than a sudden spike.