What problem does it solve? Transactional emails often fail silently: optional provider tokens turn sends into no-ops, development runs mail real users, plaintext parts go missing, and nobody can answer whether a recipient actually got the message. This Skill defines a safe pattern for wiring providers like Postmark, Resend, SendGrid, or SES so every environment sends through a sandbox key and every send is recorded. ## Core Features & Use Cases - Required provider token: Declares the provider API token as mandatory in lib/env/server.ts with no .optional(), so a misconfigured deploy fails fast instead of silently skipping sends. - Sandbox keys outside production: Routes development, CI, and preview environments through provider sandbox keys that accept messages without delivering them to real users. - Dual-part templates with render tests: Renders HTML and plaintext from one template and tests subject, key links, and non-empty plaintext, previewable via pnpm dev:email. - Delivery recording: Writes one row per intended send with the provider message id and a terminal status, turning delivery questions into a query. - Use Case: When adding a password-reset email, you configure the Postmark sandbox token, define the verified From address as a code constant, render both parts from one template, and record each send so support can confirm delivery. ## Quick Start Add a new transactional email for user invitations following the transactional email conventions, including the sandbox token setup and delivery row.
