Deliverability infrastructure

Built-in Tools to Keep Your Emails Out of Spam

Deliverability is not a feature you bolt on later. NexusProMail includes domain warming, authentication monitoring, bounce tracking and pre-send spam scoring in every account — from the Free plan up.

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Quick Answer

Email deliverability is the ability of an email to reach the recipient’s inbox rather than the spam folder or be blocked outright. It is determined by your sending domain’s reputation, authentication records (DKIM, SPF, DMARC), bounce rate, spam complaint rate and recipient engagement. NexusProMail includes built-in domain warming, authentication monitoring and deliverability tracking on every plan.

Key Takeaways

  • Domain reputation — not IP reputation — is the primary deliverability signal for most senders today
  • DKIM, SPF and DMARC must all be correctly configured before sending; Gmail and Yahoo now require DMARC
  • Keep hard bounce rate below 2% and spam complaint rate below 0.08% to maintain inbox placement
  • New sending domains must be warmed gradually over 6–8 weeks before sending at full volume
  • Sending to inactive contacts lowers engagement rates and directly harms sender reputation

The Five Factors That Determine Deliverability

Inbox placement is not luck. Every factor below is measurable and improvable — and every one is addressed by NexusProMail.

01Monitoring built-in

Domain Authentication

DKIM, SPF and DMARC are the baseline for any sending domain. Without them, major inbox providers reject or filter your email by default. NexusProMail guides you through DNS setup with one-click verification and live DNS health checks.

02Automatic protection

Sending Reputation

Inbox providers track every bounce, complaint and unsubscribe associated with your sending domain and IP. NexusProMail automatically removes bad addresses and pauses sending if your bounce rate exceeds safe thresholds.

03AI-powered engine

Domain Warmup

New sending domains have no reputation. The warming engine starts at 500 emails/day and scales up over 4–6 weeks, building reputation gradually with the major inbox providers before you reach full volume.

04Import validation

List Quality

Sending to stale, invalid or purchased addresses is the fastest route to the spam folder. NexusProMail deduplicates on import, catches invalid formats and tracks engagement scores so you can segment or suppress inactive contacts.

05Pre-send AI check

Content & Spam Score

Every email is scored 0–100 against spam filters before you send. The AI engine rewrites flagged phrases and checks your HTML for common spam triggers — subject lines, link ratios and image-to-text balance.

Domain Warming Engine

From 500 to 100,000 emails/day — safely

A new domain sent at full volume immediately will get blocked. The warming engine ramps volume over 4–6 weeks, monitors bounce and complaint rates at each stage, and auto-pauses if anything looks off.

  • ✓AI-managed ramp schedule
  • ✓Auto-pause on bounce spike
  • ✓Real-time domain health score
  • ✓Works alongside your existing DNS
Read the complete domain warming guide →
Warming schedule — example domain
Week 1500/dayBuilding baseline
Week 21,500/dayReputation growing
Week 35,000/dayGood standing
Week 415,000/dayEstablished
Week 6100,000/day✓ Fully warmed

Deliverability Metrics in Every Account

✓Open rate by campaign
✓Click rate by campaign
✓Hard bounce tracking
✓Soft bounce tracking
✓Spam complaint rate
✓Unsubscribe rate
✓Domain health score
✓DKIM/SPF/DMARC status
✓Per-campaign spam score
✓Engagement scoring (0–100)
✓Send volume over time
✓Suppression list growth
See full feature list →

Deliverability Questions Answered

What is email deliverability?+
Email deliverability refers to the ability of an email to reach the recipient's inbox rather than their spam folder or be rejected outright. It is affected by your sending domain reputation, authentication records (DKIM, SPF, DMARC), engagement rates and list quality.
What is domain warming?+
Domain warming is the process of gradually increasing email send volume from a new sending domain over several weeks. Inbox providers use sending history to assess reputation — starting slow and increasing volume prevents your domain being flagged as a source of spam.
How does NexusProMail help with deliverability?+
NexusProMail includes a domain warming engine, real-time DKIM/SPF/DMARC monitoring, spam score checking, bounce rate tracking, automatic suppression of hard bounces and complaints, and send-time pausing when bounce rates spike.
What DKIM, SPF and DMARC records do I need?+
SPF tells receiving servers which IPs are allowed to send on your domain's behalf. DKIM adds a cryptographic signature to every email that receivers can verify. DMARC tells receivers what to do when authentication fails — and sends you reports. All three are required for reliable inbox placement.
How long does domain warming take?+
A new domain typically takes 4–8 weeks to warm properly, depending on the volume you need to reach. NexusProMail's warming engine starts at 500 emails/day and increases automatically, pausing if bounce rates exceed safe thresholds.
What is a good email deliverability score?+
Tools like mail-tester.com score your setup out of 10. A score of 9.5 or above indicates strong technical configuration. NexusProMail's built-in spam checker scores emails 0–100 before you send, so you can fix issues before they affect your reputation.

Start sending with confidence

Domain warming, DMARC monitoring and spam scoring included on every plan.

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Also read: Domain warming guide · API integration guide · GDPR email marketing · Transactional email API · Email deliverability blog