Email Deliverability Guide
Everything that determines whether your email lands in the inbox or gets buried in spam. This hub collects our best deliverability resources — from DNS authentication to warm-up schedules to ongoing reputation management.
What is email deliverability?
Email deliverability is the ability to land in a recipient's primary inbox — not the spam folder, not the promotions tab, and not bounced back. It depends on three pillars: sender authentication (SPF, DKIM, DMARC), sender reputation (bounce rates, complaint rates, engagement), and content quality (avoiding spam triggers, clean HTML, proper text-to-image ratios).
Most deliverability problems come from skipping one of these pillars. A perfectly authenticated domain still lands in spam if the content is flagged. Great content still bounces if your DNS records are misconfigured. And both fail if your sender reputation is damaged from sending to stale or purchased lists.
The guides below cover each pillar in depth — start with whichever is most relevant to your current situation, or read them in order for a complete walkthrough.
Core deliverability guides
How to Avoid the Spam Folder
A step-by-step checklist covering domain authentication, list hygiene, content signals, and sending patterns that keep you in the inbox. Start here if your emails are landing in spam.
Email Warm-Up Playbook
A day-by-day plan to warm up a new sending domain: prerequisites, ramp schedule, metrics to watch, and when to pause or roll back. Essential for new domains and IP addresses.
Key deliverability topics
SPF, DKIM & DMARC setup
These three DNS records prove to inbox providers that your emails are really from you. Without them, your messages are far more likely to be flagged as spam or spoofed.
Follow the domain setup guide →Bounce rate management
High bounce rates damage your sender reputation fast. SendTrim automatically tracks hard and soft bounces, suppresses invalid addresses, and warns you before your bounce rate reaches dangerous thresholds. Keep your lists clean by removing unengaged contacts regularly and always validating before import.
List hygiene & email validation
Validating email addresses before sending prevents bounces and protects your domain reputation. Run your list through validation to catch typos, disposable addresses, and inactive mailboxes.
Try the SendTrim email validation tool →Sending reputation monitoring
Your sender reputation is a score that inbox providers assign based on your historical sending behavior. It factors in bounce rates, spam complaints, engagement metrics, and authentication status. A strong reputation means your emails get delivered; a poor one means even good content goes to spam. Monitor your reputation continuously and react quickly to any drops.