← Back to Operational Notes Archive Engineering Operational Note · Published Production Engineering Memo · Technical Architecture · 14 min read Executive Summary Separating Signal from Noise in SMTP Accounting Logs SMTP accounting logs contain thousands of events per hour. Not all carry equal diagnostic weight. Architecture Scope Fleet Scale High-Volume Infrastructure Production Status 100% […]
← Back to Operational Notes Archive Engineering Operational Note · Published Production Engineering Memo · Technical Architecture · 14 min read Executive Summary Email Compliance Infrastructure: CAN-SPAM and GDPR Side by Side CAN-SPAM and GDPR both govern bulk email, but they have different philosophies, different requirements, and different compliance infrastructure… Architecture Scope Fleet Scale High-Volume […]
← Back to Operational Notes Archive Engineering Operational Note · Published Production Engineering Memo · Technical Architecture · 14 min read Executive Summary Why Dedicated Infrastructure Scales Differently Than Shared ESPs Shared ESPs and dedicated sending infrastructure scale along different curves. At low volume, shared ESPs win on simplicity and cost. Architecture Scope Fleet Scale […]
← Back to Operational Notes Archive Engineering Operational Note · Published Production Engineering Memo · Technical Architecture · 14 min read Executive Summary Operational Protocols for Managing IP Reputation Events IP reputation events — blacklistings, SNDS status changes, Postmaster Tools IP reputation declines — require structured response protocols. 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 How Retry Storms Occur and Why They Damage Sender Reputation A retry storm is when deferred messages accumulate faster than they clear, causing exponential growth in SMTP connection attempts to an ISP. […]
← Back to Operational Notes Archive Engineering Operational Note · Published Production Engineering Memo · Technical Architecture · 14 min read Executive Summary Measuring Email Infrastructure ROI: A Framework for Justifying Investment Email infrastructure investment is often approved on instinct rather than evidence. Architecture Scope Fleet Scale High-Volume Infrastructure Production Status 100% Inboxing Verified deliverability […]
← Back to Operational Notes Archive Engineering Operational Note · Published Production Engineering Memo · Technical Architecture · 14 min read Executive Summary Infrastructure Response to Sudden Volume Spikes: What to Do and What Not to Do Sudden volume spikes — from a product launch, acquired list, or accidental re-send — stress email infrastructure in […]
← Back to Operational Notes Archive Engineering Operational Note · Published Production Engineering Memo · Technical Architecture · 14 min read Executive Summary The Deliverability Impact of Sending from New Geographic Regions Adding new sending geographies — new datacenter locations, new regional IP pools — affects deliverability through PTR record expectations… Architecture Scope Fleet Scale […]
← Back to Operational Notes Archive Engineering Operational Note · Published Production Engineering Memo · Technical Architecture · 14 min read Executive Summary Designing a DKIM Key Management System for Multi-Tenant Infrastructure Multi-tenant email infrastructure requires DKIM key management at scale: separate key pairs per tenant, independent rotation schedules, secure key… Architecture Scope Fleet Scale […]
← Back to Operational Notes Archive Engineering Operational Note · Published Production Engineering Memo · Technical Architecture · 14 min read Executive Summary Header Hygiene in High-Volume Sending: What ISP Filters Inspect ISP filters evaluate email headers at delivery time. Malformed headers, missing required fields, inconsistent From/Reply-To combinations, and… Architecture Scope Fleet Scale High-Volume Infrastructure […]