# Task 010 — Email Sending Engine

## Objective

Implement SMTP sending pipeline for prepared campaign recipients.

## Status

Completed.

## Notes

- Campaign preparation and recipient generation were completed in Task 009.
- This task will execute actual sending and status transitions.

## Completed scope

- Added SMTP transport verification/sending service.
- Added email rendering with template variables and tracking injection.
- Added campaign batch sending and single-recipient sending APIs.
- Added open/click tracking API routes with campaign/recipient status updates.
- Added `/email-test` protected page for SMTP verify and test send.
- Updated campaign detail UI with send actions and richer recipient delivery columns.
- Updated environment configuration and docs.

## Acceptance checklist

- [x] `npm run build` succeeds.
- [x] `npm run lint` succeeds.
- [x] SMTP env variables validated safely.
- [x] `/api/email/verify-smtp` implemented.
- [x] `/email-test` page implemented.
- [x] Campaign batch and single recipient sending implemented.
- [x] `CampaignRecipient` status updates to `sent/failed` and tracks open/click.
- [x] `EmailMessage` records are created and updated.
- [x] Campaign stats recalculation integrated after send/open/click.
- [x] Open tracking returns a transparent pixel.
- [x] Click tracking validates URL and redirects safely.