← Back to Operational Notes Archive Engineering Operational Note · Published Production Engineering Memo · Technical Architecture · 14 min read Executive Summary SMTP Pipelining and Deliverability Implications SMTP pipelining allows multiple commands to be sent before waiting for responses. Architecture Scope Fleet Scale High-Volume Infrastructure Production Status 100% Inboxing Verified deliverability standard MTA Engine […]
← Back to Operational Notes Archive Engineering Operational Note · Published Production Engineering Memo · Technical Architecture · 14 min read Executive Summary Why Email Infrastructure Decisions Compound Over Time IP reputation, domain reputation, ISP relationships, and list quality are all compounding assets. Good infrastructure decisions accumulate advantage. Architecture Scope Fleet Scale High-Volume Infrastructure Production […]
← Back to Operational Notes Archive Engineering Operational Note · Published Production Engineering Memo · Technical Architecture · 14 min read Executive Summary Why the Sending Domain Matters as Much as the Sending IP Email infrastructure discussion often focuses on IP reputation. Architecture Scope Fleet Scale High-Volume Infrastructure Production Status 100% Inboxing Verified deliverability standard […]
← Back to Operational Notes Archive Engineering Operational Note · Published Production Engineering Memo · Technical Architecture · 14 min read Executive Summary Technical Requirements for Large-Scale Newsletters Operational guide to the technical requirements for running a large-scale newsletter in 2026. Architecture Scope Fleet Scale High-Volume Infrastructure Production Status 100% Inboxing Verified deliverability standard MTA […]
← Back to Operational Notes Archive Engineering Operational Note · Published Production Engineering Memo · Technical Architecture · 14 min read Executive Summary Feedback Loops: How They Work and Why Every Operator Needs Them ISP Feedback Loop programs send complaint reports to senders when recipients mark messages as spam. Architecture Scope Fleet Scale High-Volume Infrastructure […]
← Back to Operational Notes Archive Engineering Operational Note · Published Production Engineering Memo · Technical Architecture · 14 min read Executive Summary Logging as a First-Class Concern in Email Infrastructure Email infrastructure that logs poorly operates blind. This note argues for treating logging as a first-class engineering concern from day one — not… Architecture […]
← Back to Operational Notes Archive Engineering Operational Note · Published Production Engineering Memo · Technical Architecture · 14 min read Executive Summary SMTP Timeout Configuration and Its Effect on Delivery Behaviour SMTP timeouts control how long the sending MTA waits at each stage of an SMTP session. Architecture Scope Fleet Scale High-Volume Infrastructure Production […]
← Back to Operational Notes Archive Engineering Operational Note · Published Production Engineering Memo · Technical Architecture · 14 min read Executive Summary Authentication Is Table Stakes, Not a Differentiator SPF, DKIM, and DMARC are no longer advanced email deliverability practices. They are the baseline requirement for inbox delivery at scale. Architecture Scope Fleet Scale […]
← Back to Operational Notes Archive Engineering Operational Note · Published Production Engineering Memo · Technical Architecture · 14 min read Executive Summary Infrastructure Foundations for Cold Email at Scale How to architect cold email infrastructure that survives at volume in 2026: total IP and domain separation from marketing traffic, the MTA topology that… Architecture […]
← Back to Operational Notes Archive Engineering Operational Note · Published Production Engineering Memo · Technical Architecture · 14 min read Executive Summary Building Observable Email Infrastructure: Logging and Alerting Design What logging and alerting infrastructure high-volume email operations require to catch delivery problems before they become incidents. Architecture Scope Fleet Scale High-Volume Infrastructure Production […]