Email Deliverability Audit and Authentication Checklist

A beautifully written lifecycle programme has no commercial value when mail is rejected, filtered, or sent to people who never expected it. Deliverability is the result of identity, permission, infrastructure, list quality, content, volume, and recipient behaviour working together.

This checklist gives marketing, operations, and technology teams a shared audit path. It does not promise inbox placement. It helps identify controllable risks before a business increases automated or campaign volume.

This article is a supporting decision guide for Scallar's email automation service. It explains a specific implementation or buying decision without replacing the service page or its scope and pricing guide.

Verify the Sending Identity

Inventory every system allowed to send using the business domain: marketing platform, CRM, ecommerce platform, helpdesk, transactional provider, forms, and legacy tools. Unknown senders create authentication gaps and make incident diagnosis difficult.

Review SPF coverage and lookup limits, DKIM signing and alignment, DMARC policy and reporting, return-path alignment, TLS support, and visible From and reply addresses. Changes should be made by someone who understands DNS dependencies; a rushed edit can interrupt legitimate mail.

Separate Message Purpose and Infrastructure

Transactional, support, sales, and marketing messages have different expectations and risk. Appropriate subdomain and stream design can improve ownership and diagnosis, but separation is not permission to send poor-quality mail.

Document which system sends each message type, the legal and consent basis, the expected volume, the unsubscribe or preference path, and the operational owner. Keep critical account communication from being entangled with avoidable marketing reputation problems.

Audit Acquisition and Consent

Trace how every address enters the database. Review forms, imports, events, partner sources, checkout, offline collection, and CRM creation. Purchased or unclear lists create complaint, legal, and brand risk and should not be made respectable by cleaning software.

Store source, timestamp, consent context, and preference where appropriate. Make unsubscribe easy and effective across connected systems. A person removed in the email platform should not be silently re-added by the CRM integration.

Inspect Engagement and List Hygiene

Review hard bounces, repeated soft bounces, complaints, inactive recipients, role addresses, duplicates, malformed entries, and sudden list growth. Define suppression and re-engagement rules before continuing to send indefinitely.

Engagement decline may signal irrelevant content, excessive frequency, weak acquisition, seasonal behaviour, or inbox placement issues. Segment diagnosis before deleting history or making a large volume change.

Review Content and Sending Behaviour

Check sender recognition, subject accuracy, link destinations, redirects, image dependence, text balance, accessibility, mobile rendering, tracking domains, and the consistency of message purpose. Avoid deceptive urgency or misleading reply chains.

Inspect volume patterns and recent changes. Large spikes from a new domain or dormant list deserve controlled ramp-up and close monitoring. Scheduling should respect audience context, but timing cannot repair weak consent or authentication.

Build Monitoring and Incident Response

Create a regular dashboard for delivery, rejection, bounce, complaint, unsubscribe, engagement, and downstream outcomes by provider, domain, message stream, and journey. Monitor DMARC reports and provider postmaster data where available.

Define who pauses sending, investigates a block, contacts providers, corrects a source, validates recovery, and records the change. Deliverability is an operating discipline, not a one-time technical setup.

Deliverability Audit Checklist

1. Inventory every platform and domain that sends email for the business.
2. Validate SPF, DKIM, DMARC, alignment, reply paths, and tracking domains.
3. Separate transactional and promotional ownership where operationally useful.
4. Trace acquisition source, consent, preferences, and unsubscribe propagation.
5. Review bounces, complaints, inactive segments, duplicates, and import history.
6. Inspect sender identity, content accuracy, links, accessibility, and mobile output.
7. Control volume changes and monitor provider-specific results.
8. Document incident ownership, pause criteria, remediation, and recovery checks.

How to Read the Evidence

The D2C retention case study provides an adjacent example of lifecycle ownership and segmentation. It is not evidence of guaranteed deliverability; authentication and sender reputation must be evaluated for each sending environment.

Case studies should be used as evidence of the workflow, handoff, integration, or delivery method they actually document. An adjacent case does not prove that every organisation will achieve the same outcome. A responsible buyer should compare the starting process, data quality, team ownership, scope, and measurement method before drawing conclusions.

Continue Through the Authority Cluster

• Email automation implementation guide
• Email automation service
• Email automation pricing
• B2B nurture and CRM guide
• D2C retention workflow evidence

These links are intentionally selective. They connect this supporting article to the main service, commercial scope, adjacent implementation decisions, and relevant delivery evidence so readers can move through the topic without landing on multiple pages that compete for the same intent.

Research and Standards Consulted

• Google email sender guidelines
• Google sender guideline FAQ
• HubSpot email deliverability overview

External references are included for implementation context and risk awareness. Product capabilities, platform rules, and technical requirements change; confirm current vendor documentation during discovery rather than treating any article as a substitute for a live technical assessment.