Send an opt-in approval email to a recipient. GoodSender dispatches a verification link. Statuses after call: unverified → verification_sent.
Look up the current verification lifecycle state for any address. Possible statuses: unverified · verification_sent · failed · approved · rejected. Returns 404 if address is unknown.
Send a transactional email via a predefined template. No recipient consent required. Returns "rejected" if recipient has explicitly opted out. Unknown recipients are auto-registered as unverified.
Send a custom email to a recipient who has approved status. Supports plain text, HTML, and Markdown (rendered server-side). Unverified or rejected recipients will be silently skipped.