Signals, not one rule
Filters weigh dozens of signals: authentication, links, words, images-to-text ratio, how many people mark you as spam, and your sending history.
The fastest way to spam
Buying lists, misleading subject lines, all-image emails and no easy unsubscribe are quick ways to get filtered. Permission and clarity keep you safe.
Warm up and stay consistent
A brand-new domain sending hundreds of emails looks suspicious. Start small, send consistently, and let reputation build.
Key takeaway
Start small and send consistently — let reputation build before you scale up.