How to Improve Your Email Deliverability Rate
Deliverability starts long before you hit send. This guide covers sender reputation, list hygiene, bounce management, and more.
What is email deliverability?
Email deliverability is the percentage of your emails that actually reach the recipient's inbox — not their spam folder, and not a bounce. It's different from delivery rate, which only measures whether the receiving server accepted the message at all.
An email can be "delivered" but still land in spam. True deliverability means reaching the inbox, and it depends on a combination of technical setup, sender reputation, and content quality.
Build and protect your sender reputation
Mailbox providers like Gmail, Outlook, and Yahoo assign a reputation score to your sending domain and IP address. This score is based on your sending history: bounce rates, spam complaints, engagement levels, and authentication status.
A new domain has no reputation, which is why you should warm it up gradually. Start by sending to your most engaged contacts — people who are certain to open and click. Over several weeks, slowly increase your volume as your reputation builds.
Avoid sudden spikes in volume. Going from 100 emails per day to 10,000 overnight is a red flag that triggers spam filters. Consistent, gradual growth signals legitimacy.
Keep your list clean
List hygiene is one of the most impactful things you can do for deliverability. Remove invalid addresses immediately after a hard bounce. Set up automated rules to suppress addresses that haven't engaged in 90 or 180 days.
Never purchase email lists. Bought lists contain spam traps — addresses specifically designed to catch unsolicited senders. Hitting even one spam trap can devastate your reputation.
Use double opt-in for new subscribers when possible. It adds a small friction point, but it ensures that every address on your list belongs to someone who genuinely wants to hear from you.
Authenticate your domain
SPF, DKIM, and DMARC are non-negotiable in 2026. Google and Yahoo both require proper authentication for senders sending more than 5,000 emails per day, and other providers are following suit.
RemindMe sets up authentication automatically when you add your domain. If you're using multiple sending services, make sure each one is included in your SPF record and has its own DKIM key configured.
Write content that avoids spam triggers
Spam filters analyze your email content for patterns associated with spam. Avoid ALL CAPS subject lines, excessive exclamation marks, and phrases like "Act now!!!" or "Free money." These are obvious triggers, but subtler ones exist too.
Maintain a healthy text-to-image ratio. Emails that are mostly images with little text often get flagged. Always include a plain-text version alongside your HTML email.
Include a visible, working unsubscribe link. Not only is this legally required in most jurisdictions, but one-click unsubscribe is now mandatory for bulk senders under Google's guidelines.
Monitor your metrics
Watch your bounce rate (should be under 2%), spam complaint rate (should be under 0.1%), and engagement metrics closely. A sudden drop in open rates or a spike in complaints is an early warning sign.
RemindMe's analytics dashboard tracks these metrics in real time. Set up alerts to notify you when any metric crosses a threshold so you can investigate before it impacts your reputation.