A practical evaluation framework for choosing a transactional email provider — the criteria that matter in production, how to test them before committing, and the costs that only appear later.
The three ways to send transactional email, how to choose between them, and the architecture decisions — queueing, retries, template storage — that decide whether it holds up in production.
A working Node.js implementation — sending by API, queueing dispatch, handling retries idempotently, and keeping templates out of your repository.
What a transactional email is, how it differs from marketing email, the 15 most common types, and how sending actually works — from API call to inbox.