Deliverability manual
How inbox placement works, what you control, and what to do when it goes wrong.
Foundations
Understanding Email DeliverabilityLearn what email deliverability really means and why it’s different from simple email delivery.Signal FlowSee how signals move between senders, receivers, and mailbox providers to shape inbox decisions.Value ChainUnderstand the key players in email and how each one influences deliverability outcomes.The Signal GameExplore how mailbox providers score emails using history, reputation, and engagement patterns.
Controllables
Authentication & Identity ControlBuild trust with mailbox providers through SPF, DKIM, and DMARC alignment.Infrastructure & Routing StrategiesLearn how your sending IPs, domains, and routing choices impact reputation.List Quality & Acquisition IntegrityWhy a clean, engaged list matters more than anything else for long-term inboxing.Engagement EconomicsUnderstand how opens, clicks, and complaints drive inbox placement decisions.
The Reputation Engine
Understanding Mailbox Provider AlgorithmsPeek into how Gmail, Outlook, and others score your emails behind the scenes.How Senders Earn Long-Term InboxingMove from unknown sender to trusted sender with consistent, positive signals.Red Flags: Spam Traps, Complaints & BlacklistsAvoid the signals that can instantly damage your reputation and inbox rates.
The Human Layer
CAN-SPAM, GDPR, & CASLStay compliant with key global email laws that protect user privacy and trust.Content Psychology & Filtering SignalsWhy content rarely causes spam placement—and the subtle signals that still matter.User Expectations & EngagementHow user behavior shapes reputation far more than content or infrastructure.
Playbooks & Diagnostics
Inbox Placement TestingLearn practical ways to test and monitor where your emails actually land.Analyzing SMTP LogsDecode SMTP logs to spot delivery issues before they become major problems.Incident: Soft BouncesUnderstand why soft bounces happen and how to respond effectively.Incident: Block BouncesLearn to diagnose and resolve hard blocks that stop mail at the gate.Incident: Reputation Tanking OvernightSteps to take when your sender reputation suddenly collapses.Google Postmaster Tool: Access ControlManage access to Google Postmaster Tools for better visibility into Gmail deliverability.When to Reach PostmasterKnow when and how to contact mailbox providers for help with delivery issues.Scaling Without Breaking DeliverabilityScale your email volume safely without triggering reputation penalties.
Advanced Strategies
Domain Strategy for Complex SendersLearn how to manage multiple domains and subdomains for optimal deliverability.Traffic ShapingControl sending speed and patterns to stay within mailbox provider thresholds.Deliverability as a Business LeverTurn strong deliverability into a measurable business advantage.
Future of Email Deliverability
AI Filters & User-Level TrustExplore how AI filters and per-user trust models are reshaping inbox placement.AI and DeliverabilitySee how AI-driven tools will transform email deliverability practices.Beyond Deliverability OpsImagine what email operations look like in a world beyond traditional deliverability.