Email deliverability for Customer Insights – Journeys

Email deliverability — the fraction of emails that actually land in the recipient's inbox rather than spam — is the single largest determinant of marketing email ROI. Customer Insights – Journeys gives you the tools; the configuration discipline is the customer's responsibility.

The sending architecture. Customer Insights – Journeys sends through Microsoft's email infrastructure with the customer's sending domain as the visible "from" address. The mechanics:

• Email comes from marketing@customer.com (or whatever sender the customer configures).
• But it's sent through Microsoft's mail servers — not the customer's own mail relay.
• DNS records on customer.com tell receiving servers that Microsoft's servers are authorised to send on behalf of customer.com.

The required DNS records.

• SPF (Sender Policy Framework) — a TXT record listing IPs/domains authorised to send for the domain. Customer Insights – Journeys provides the include statements to add.
• DKIM (DomainKeys Identified Mail) — cryptographic signing of outgoing email. Microsoft generates a key pair; the customer adds the public key as a DNS TXT record. Each outgoing email is signed with the private key; receiving servers verify the signature against the published public key.
• DMARC (Domain-based Message Authentication, Reporting & Conformance) — a policy DNS record declaring what should happen to email that fails SPF/DKIM (none / quarantine / reject) and where to send aggregate reports.

Without all three, deliverability suffers across major email providers (Gmail, Outlook, Apple Mail, Yahoo). Setting them up before first send is non-negotiable.

Sending subdomain. Best practice is to send marketing email from a dedicated subdomain (e.g. mail.customer.com or news.customer.com), separate from transactional and personal email on the main domain. A reputation problem on the marketing subdomain doesn't poison the main domain. Microsoft recommends and supports this pattern.

IP warm-up. New sending IPs have no reputation; sending high volume from a cold IP triggers spam-folder routing. Warming up:

1. Week 1: 1,000–5,000 emails to highly-engaged contacts only.
2. Week 2–3: gradually increase to full volume, prioritising contacts likely to open and click.
3. Avoid bursts to unverified addresses early in the warm-up.

The platform handles the IP pool; the customer's responsibility is content quality and list hygiene during the warm-up window.

List hygiene. Major drivers of deliverability collapse:

• High bounce rate — sending to invalid addresses signals you don't manage your list. Validate addresses on capture; remove repeated hard bounces.
• Spam complaints — recipients clicking "report spam" damages reputation. Make unsubscribe prominent; honour it instantly.
• Low engagement — Gmail and Outlook downrank senders whose recipients consistently ignore the mail. Suppress disengaged contacts after configurable periods.

Content quality. Email content drives spam-filter scoring:

• Subject lines — avoid spammy phrasing ("FREE!!!", "100% guaranteed", excessive punctuation, all caps).
• Image-to-text ratio — image-only emails get flagged; balance with real text content.
• Links — too many, or links to dubious domains, hurt scoring.
• Unsubscribe link — required by CAN-SPAM, GDPR, and similar regulations. Customer Insights – Journeys auto-inserts; ensure it works.

Monitoring. Built-in dashboards track delivery rate, bounce rate, open rate, click rate, spam-complaint rate per send. Postmaster Tools (Gmail, Microsoft) provide additional signal. Anomalies require investigation — sudden drops are usually configuration issues or reputation problems.

Operational reality. Deliverability is a discipline, not a one-time setup. Audit DNS records quarterly; review engagement metrics weekly; act on bounces and complaints monthly.