Why spam scoring matters in development
Most developers discover their transactional emails land in spam after deploying to production. By then, users aren't receiving password resets, order confirmations, or magic links — and support tickets pile up.
MailHog catches these issues at the source. Every email captured by your test inbox is automatically scored for spam indicators using a heuristic engine compatible with rspamd, the same engine used by major email providers.
What the spam analysis shows you
0–3
Clean
Likely to land in inbox.
3–5
Warning
Some indicators detected. Review rules.
5–8
Likely spam
Multiple spam signals detected.
8+
Spam reject
Would be rejected by most mail servers.
Triggered rules with score breakdown
MailHog tells you why an email scores high. Every triggered rule is listed with its score contribution:
URIBL_BLOCKED → +2.5 — URI in blocklist
DMARC_REJECT → +2.0 — DMARC policy violation
ALL_CAPS_SUBJ → +1.2 — Subject in all capitals
SUSP_TLD_TK → +1.0 — Suspicious TLD
Total: 6.7 — Likely spam
DMARC_REJECT → +2.0 — DMARC policy violation
ALL_CAPS_SUBJ → +1.2 — Subject in all capitals
SUSP_TLD_TK → +1.0 — Suspicious TLD
Total: 6.7 — Likely spam
Common spam triggers developers miss
- Missing or misconfigured SPF/DKIM/DMARC records
- ALL CAPS in subject lines or body text
- Suspicious URIs or link shorteners in email body
- Missing unsubscribe headers on transactional emails
- HTML-only emails without plain text multipart fallback
- Sending from domains with no reverse DNS
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