# Email & Campaigns

Email is a product surface here, not just transactional plumbing. The platform
runs **bulk marketing campaigns**, tracks how they perform, and protects sender
reputation — all on top of AWS SES.

## Transactional email

Fifteen mailers cover the lifecycle of the store — orders, OTPs, wishlists,
flash sales, gift cards, payouts, vendor applications, and more. They share an
`ApplicationMailer` base, render HTML-only emails, and are always delivered via
`deliver_later` so a slow mail provider never blocks a web request.

## Marketing campaigns

`EmailCampaign` drives bulk sends:

- **Audience segmentation** — `CampaignAudienceService` builds the recipient
  list from user segments rather than blasting everyone.
- **Block-based composition** — `CampaignBlockRenderer` assembles a campaign
  from content blocks; `CampaignHtmlSanitizer` keeps the output safe.
- **Delivery** — `SendEmailCampaignJob` fans the send out across background
  workers, throttled by `EmailSendRateLimiter` to stay within SES limits.

## Tracking

Every campaign send is measured:

- **Open tracking** — a tracking pixel, with `EmailOpenClassifier`
  distinguishing genuine opens from prefetch noise.
- **Click tracking** — `CampaignLinkRewriter` rewrites links so clicks are
  recorded as `email_campaign_link_click` rows.
- **Attribution** — `CampaignAttributionService` ties downstream conversions
  back to the campaign that drove them.

## Protecting deliverability

Sending bulk mail badly gets a domain blocklisted. The platform guards against
that:

- **Bounce & complaint handling** — `email_bounces` and `email_complaints`
  capture SES feedback.
- **Suppression** — `EmailSuppressionService` ensures addresses that bounced or
  complained are never mailed again.
- **Newsletters** — `NewsletterSubscription` supports double-opt-in and
  tokenised one-click unsubscribe.

## Re-engagement

Email also closes the loop on shopping behaviour: abandoned-cart recovery,
abandoned-wishlist reminders, price-drop alerts, and restock notifications all
run as scheduled background jobs.

## Key files

| Concern | Files |
|---------|-------|
| Models | `EmailCampaign`, `EmailCampaignRecipient`, `EmailCampaignLinkClick`, `EmailBounce`, `EmailComplaint`, `NewsletterSubscription` |
| Services | `CampaignAudienceService`, `CampaignBlockRenderer`, `CampaignLinkRewriter`, `CampaignAttributionService`, `EmailSuppressionService`, `EmailSendRateLimiter` |
| Jobs | `SendEmailCampaignJob`, `EmailOpenClassifier` |