October 2026 Summaries

Courier has introduced preference-change webhooks and a preference history API to help organizations track when users opt in, opt out, or alter notification channels for specific topics. The new `preferences:user:updated` webhook delivers each change from any source, including hosted preference pages, unsubscribe links, in-app settings, and the API, with both current and previous values where available. The `GET /preferences/logs` endpoint provides a paginated, newest-first audit history that can be filtered by user, tenant, or time, and is supported across Courier’s server SDKs, CLI, and MCP server. Courier recommends using webhooks to maintain current CRM or database records and using the history API to recover missed events, while ensuring idempotent processing and signature verification. Preference resets that remove an override do not create events or history entries, so applications must synchronize those changes directly. The features are available now and are intended to improve compliance, customer support, and analysis of notification engagement and opt-out patterns.

Courier’s proposed end-to-end email testing workflow uses an AI coding agent, Courier’s Test environment, AgentMail inboxes, and Device Preview screenshots to send real template variants, inspect delivered messages, and identify issues before release. It recommends scripting objective checks for subjects, variables, links, authentication records, delivery status, and unexpected content, while having an agent review copy, visual rendering, dark mode, mobile layouts, and other subjective concerns that require human sign-off. The process tests normal, missing-field, and long-value data, stores approved expectations and artifacts, prevents production publishing, and reruns after fixes until all checks and reviews pass. Examples show the approach detecting staging links, blank greetings, misplaced transactional copy, incomplete delivery-date text, and misleading button labels, including defects that automated checks alone missed. The post also outlines setup, debugging delivery failures, CI integration, and the distinction between real-inbox testing and sandbox testing, emphasizing that live sends can validate providers, routing, DNS authentication, and the final user-facing email.