---
title: "Email Deliverability Guide"
description: "What decides whether your email reaches the inbox, and how to stay out of spam."
source: "https://www.mailmark.dev/guides/email-deliverability"
site: "Mailmark"
---

# Email Deliverability Guide

Reaching the inbox is only half the battle. This guide covers how to build and maintain a strong sender reputation so your emails land in the inbox, not spam.

Email deliverability is the ability of your emails to reach subscribers' inboxes. The major factors are domain authentication, sender reputation, email content, and list quality. Neglecting any one of them can route your email to spam or get it blocked entirely.

## Healthy benchmarks

| Metric | Target |
| ------ | ------ |
| Open rate | > 20% |
| Click rate | > 2% |
| Bounce rate | < 2% |
| Spam complaint rate | < 0.1% |
| Unsubscribe rate | < 0.5% |

## 1. Authenticate your domain

- Set up SPF, DKIM, and DMARC records (see the [DNS Setup Guide](/guides/dns-setup)).
- Use a custom domain. Never send campaigns from @gmail.com or @yahoo.com.
- Start with DMARC policy `p=none`, then graduate to `p=quarantine` as you gain confidence.

## 2. Warm up your sending IP

- Start with small volumes (50-100/day) and increase by 30-50% every 3-5 days.
- Send to your most engaged contacts first. High open rates signal good sender reputation.
- Avoid large one-off blasts. Consistent daily volume beats spikes.

## 3. Maintain list hygiene

- Remove hard bounces immediately and soft bounces after 3-5 attempts.
- Remove contacts who have not engaged in 90+ days, or run a re-engagement campaign first.
- Never purchase email lists. They contain spam traps and dramatically hurt deliverability.
- Use double opt-in for new subscribers.

## 4. Write better email content

- Avoid spam trigger words like "FREE!!!", "Act now", "Guaranteed", "No risk".
- Maintain a healthy text-to-image ratio (more text than images).
- Always include a plain-text version of your email.
- Use a clear, recognisable sender name and reply-to address.

## 5. Monitor your metrics

- Keep open rate above 20% and click rate above 2%. Lower rates signal disengagement.
- Keep bounce rate below 2% and spam complaint rate below 0.1%.
- Monitor your domain's reputation with Google Postmaster Tools and Senderscore.org.
- Set up bounce and complaint webhook handlers to act on events in real time.

## 6. Send at the right time

- Tuesday to Thursday, 9 to 11 am recipient local time, consistently outperform other windows.
- Avoid major holidays and Fridays for B2B audiences.
- Test send times with A/B splits and let the data guide you.

## Quick summary

Great deliverability comes down to three things: proving you are who you say you are (authentication), earning trust over time (sender reputation), and respecting your recipients (list hygiene and content quality). Mailmark handles the technical infrastructure. The rest is up to you.

## Related

- [DNS Setup Guide](/guides/dns-setup)
- [Email Warmup](/docs/warmup)
- [Deliverability checker](/tools/email-deliverability-checker)

---

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