10 ways to land in the inbox, not spam

Deliverability isn't luck — it's a set of signals mailbox providers read every time you send. Get these right and your open rates take care of themselves.

1. Authenticate your domain (SPF, DKIM, DMARC)

These three records tell inbox providers your mail is really from you. SPF lists who can send for your domain, DKIM cryptographically signs each message, and DMARC ties it together. GO MAILBOX generates DKIM keys for you in a click.

2. Warm up new domains

A brand-new domain has no reputation. Sending 100,000 emails on day one looks like spam. Ramp up gradually over about two weeks so providers learn to trust you.

3. Only email people who asked

Permission is everything. Use double opt-in for signups so every subscriber genuinely wants your email. It's the single biggest predictor of inbox placement.

4. Keep your list clean

Remove hard bounces and long-term non-openers. A smaller, engaged list beats a huge, stale one every time. Automatic bounce handling and suppression do this for you.

5. Make unsubscribing easy

A visible unsubscribe link reduces spam complaints — which hurt far more than an unsubscribe ever will. GO MAILBOX adds a compliant unsubscribe footer automatically.

6. Watch your complaint rate

Keep spam complaints under 0.1%. If people mark you as spam, providers notice fast. Relevant content to a permission-based list keeps complaints low.

7. Balance images and text

An email that's one giant image trips spam filters. Use real text, a sensible image-to-text ratio, and always include alt text.

8. Avoid spammy words and tricks

ALL CAPS subject lines, "FREE!!!", and hidden text are red flags. Write like a human writing to a human.

9. Send consistently

Irregular giant bursts look suspicious. A steady, predictable sending rhythm builds a stable reputation.

10. Measure and adjust

Track opens, clicks, bounces and unsubscribes on every send. If a metric slips, investigate before it becomes a reputation problem.