Transactional email is the email your users depend on: password resets, order confirmations, receipts, account alerts. If it lands in spam, your product breaks. Here is the exact setup that keeps it in the inbox.
Transactional email is different from marketing email in one critical way: the user expects it and often needs it. A password reset that lands in spam is a support ticket. An order confirmation that lands in spam is a lost sale. That makes transactional deliverability a reliability problem, not a growth problem.
This guide covers the full setup: authentication, sending infrastructure, list hygiene, and ongoing monitoring.
Receivers (Gmail, Microsoft, Yahoo) require authenticated mail. Transactional domains are no exception. You need all three:
p=none, move to p=quarantine, then p=reject as you gain confidence.A minimal, safe DMARC policy for a new transactional domain:
v=DMARC1; p=none; pct=100; rua=mailto:dmarc@yourdomain.com; aspf=r; adkim=r
Check your current records in one click, or use the DMARC generator to build a safe policy.
Transactional email should come from a dedicated IP, not a shared one. Shared IPs inherit the reputation of everyone else sending from them. A dedicated IP means your reputation is yours alone.
When you get a new dedicated IP, warm it up over 2-4 weeks: start with a small volume and increase gradually. Jumping from 0 to 100k emails a day on a fresh IP is the fastest way to hit spam filters.
| Week | Daily volume | Goal |
|---|---|---|
| 1 | 500-1,000 | Establish baseline, confirm auth passes |
| 2 | 5,000-10,000 | Build sending history |
| 3 | 25,000-50,000 | Scale as reputation holds |
| 4 | Full volume | Steady-state sending |
Receivers watch two numbers closely: bounce rate and complaint rate. For transactional email, both should be near zero because you are emailing people who just took an action (signed up, made a purchase, requested a reset).
Practical steps: verify addresses before sending, suppress known bounces, and make sure every transactional email has a clear "why am I getting this?" line and a way to manage preferences.
Deliverability degrades silently. A new filter update, a reputation dip, or a misconfigured DNS record can push your transactional email into spam overnight. You will not notice from the dashboard alone.
Continuous monitoring catches the problem while it is small: a drop in your deliverability score, a new blocklist listing, or a failing SPF/DKIM/DMARC check. That is exactly what Inboxproof Pro does: it re-checks your domain daily and alerts you when your score drops.
Run a full audit now. Check SPF, DKIM, DMARC, MX, TLS, PTR, and blocklists for your transactional sending domain in one click.
Audit my domain Monitor it daily (Pro)mail.yourdomain.com) for transactional.