Email deliverability. SPF, DKIM, DMARC

If your order confirmations land in spam, customers think they were scammed. Email authentication is non-optional.

The three records

You need all three on your sending domain:

• SPF. TXT record listing the IPs allowed to send from your domain. SellStein adds itself: `v=spf1 include:_spf.sellstein.com ~all`
• DKIM. Public key used to sign outgoing email. We provide a CNAME pointing at our DKIM key
• DMARC. Policy telling receivers what to do when SPF or DKIM fails. Start with `v=DMARC1; p=none; rua=mailto:dmarc@yourdomain.com` (monitor, don't block) for two weeks, then move to `p=quarantine`, then `p=reject` once you're confident

Settings → Email → Domains → Add domain

Type your domain. We show three DNS records to add at your registrar. After adding, click Verify. Most providers (Cloudflare, Route 53, Google Domains) propagate in <5 minutes.

Until verified, transactional emails go from a generic sellstein.com address. Verified domain = emails from `orders@yourdomain.com` with full reputation. Worth doing day one.

Sender reputation

Reputation is built per-IP, per-domain, over time. New domains have zero reputation. The first 1000 emails determine whether your domain is "trusted" or "suspicious". For years.

The signals that build reputation:

• Low bounce rate (<2%)
• Low spam complaint rate (<0.1%)
• High open rate (>15%)
• Authenticated (SPF/DKIM/DMARC pass)
• Consistent volume (no spikes)
• Engaged recipients (real people clicking, not bots)

The signals that destroy it:

• Buying email lists (death sentence)
• Sending to inactive addresses (bounces compound)
• Spam-trigger words ("FREE!!!", all caps, excessive emojis)
• Suddenly 10x'ing volume (looks like a compromised sender)

Warm-up

For a new domain, send slowly. Day 1: 50 emails. Day 2: 100. Day 3: 200. Double daily for two weeks until you're at your target volume. SellStein's bulk-send tool has a Warm-up mode that paces sends automatically.

Skip warm-up and your first big campaign goes straight to spam. Worse, the spam-folder placement persists for months.

Bounces and complaints

Settings → Email → Bounces. Hard bounces (recipient doesn't exist) auto-suppress. The address is added to a do-not-send list. Soft bounces (mailbox full, temporary issue) retry up to 3 times.

Complaints (recipient hit "Mark as spam") auto-unsubscribe and notify you. If complaint rate exceeds 0.3% in any 7-day window, we pause your sending and email you. This is to protect your reputation, not punish you. Sending into a spam-flagged campaign makes everything worse.

Inbox-placement testing

Before a big campaign, run Marketing → Email → Test inbox placement. We send a copy to seed accounts at Gmail, Outlook, Yahoo, Apple Mail, ProtonMail and report where each one landed. If it's in spam at any major inbox, fix the warning before sending to real customers.