Email deliverability determines whether your campaigns reach the inbox or the spam folder. This guide covers authentication (SPF, DKIM, DMARC), reputation management, and list hygiene — the three pillars of inbox placement.

→ Deliverability dictionary · Email Marketing Nepal · Open Rate

The three authentication protocols

Protocol Purpose Where configured
SPF Lists authorized sending IP addresses DNS TXT record
DKIM Cryptographic signature proving message integrity DNS TXT + ESP
DMARC Policy for failed auth + reporting DNS TXT record

All three should be configured before sending bulk marketing email.

SPF setup

Record type: TXT on root domain (@)

Email Deliverability Guide (2026): SPF, DKIM, DMARC & Inbox Placement

Example (Mailchimp):

v=spf1 include:servers.mcsv.net include:_spf.google.com ~all

Rules:

  • Only one SPF record per domain (merge includes into one)
  • ~all = soft fail (recommended during setup)
  • -all = hard fail (use once confident)
  • Maximum 10 DNS lookups in SPF chain

Verify: dig TXT yourdomain.com.np or use MXToolbox SPF checker

DKIM setup

  1. In your ESP (Mailchimp, Brevo, SendGrid) → Domain authentication
  2. ESP generates DKIM selector and public key
  3. Add CNAME or TXT record to DNS:

Example (SendGrid):

s1._domainkey.yourdomain.com → s1.domainkey.u123456.wl.sendgrid.net
  1. ESP verifies and enables signing

Verify: Send test email → view raw headers → look for DKIM-Signature: pass

DMARC setup

Record type: TXT on _dmarc.yourdomain.com

Starter policy (monitor only):

v=DMARC1; p=none; rua=mailto:dmarc@yourdomain.com; pct=100

Progression:

p=none   → monitor failures (week 1–4)
p=quarantine → send failures to spam (month 2)
p=reject → block failures entirely (month 3+, when confident)

Verify: DMARC Analyzer or Google Postmaster Tools

Authentication checklist

  • SPF record published and valid
  • DKIM signing enabled via ESP
  • DMARC record with p=none minimum
  • DMARC aggregate reports monitored weekly
  • From address uses authenticated domain (not @gmail.com)
  • Return-path / bounce domain aligned

Sender reputation factors

Factor Impact Target
Bounce rate High < 2%
Spam complaint rate Critical < 0.1%
Unsubscribe rate Moderate < 0.5% per campaign
Open rate Engagement signal > 20% (varies by industry)
List age Trust Remove inactive 6+ months

List hygiene workflow

  1. Double opt-in for marketing lists (recommended)
  2. Remove hard bounces immediately (automatic in ESP)
  3. Suppress soft bounces after 3 consecutive failures
  4. Re-engagement campaign at 90 days inactive
  5. Remove non-responders after re-engagement attempt
  6. Never purchase lists — destroys reputation permanently

Content and sending practices

  • Avoid spam trigger words in subject lines (FREE!!!, ACT NOW)
  • Maintain 60:40 text-to-image ratio
  • Include physical address and unsubscribe link (CAN-SPAM / legal)
  • Send from consistent From name and address
  • Warm up new domains: start 50/day, double weekly
  • Segment by engagement — send less to inactive subscribers

Nepal business context

Challenge Solution
Sending from cPanel @domain.com.np Use ESP with authenticated domain instead
Low Gmail deliverability SPF + DKIM + DMARC mandatory
Mixed transactional + marketing Separate subdomains: mail. for marketing, root for transactional
No dedicated IT for DNS Use ESP’s DNS setup wizard (Mailchimp, Brevo)

Monitoring tools

Tool Cost Purpose
Google Postmaster Tools Free Domain reputation with Gmail
Mail-tester.com Free Pre-send spam score check
MXToolbox Free tier SPF/DKIM/DMARC validation
ESP analytics Included Bounce, complaint, open rates

Pre-send test workflow

  1. Send to mail-tester.com address → target 9+/10
  2. Check SPF, DKIM, DMARC pass in raw headers
  3. Send to test group (5–10 internal addresses) on Gmail, Outlook, Yahoo
  4. Confirm inbox placement (not Promotions/Spam)
  5. Launch to full segment