# List Hygiene (/guides/list-hygiene)

Plunk automatically monitors the bounce and complaint rates of your emails to help maintain a health sender reputation. High bounce or complaint rates can negatively impact your deliverability and may lead to your account being suspended.

## Bounce Management

A bounce occurs when an email cannot be delivered to the recipient's inbox. Plunk records every bounce as an `email.bounce` event on the contact, and automatically unsubscribes the contact **only on permanent (hard) bounces**. Transient (soft) bounces don't change subscription state — they're typically retried by the upstream mail server.

### Types of Bounces

| Type                 | Description                                                                       | Auto-unsubscribes? |
| -------------------- | --------------------------------------------------------------------------------- | ------------------ |
| **Permanent (hard)** | Permanent delivery failure — invalid address, blocked domain, recipient rejected. | Yes                |
| **Transient (soft)** | Temporary delivery failure — mailbox full, server unavailable, greylisted.        | No                 |
| **Undetermined**     | The upstream provider couldn't classify the bounce.                               | No                 |

Both bounce types fire an `email.bounce` event you can branch on inside workflows or webhooks (use the event payload's `bounceType` field to distinguish them).

### Preventing bounces

* [Verify email addresses](/api-reference/public-api/verifyEmail) at signup before adding them to your list.
* Regularly clean your email list — segment unengaged contacts and re-confirm or remove them.
* Build a confirmation flow with a workflow that sends a verification email and only marks the contact as confirmed when they click through.

## Complaint Management

A complaint occurs when a recipient marks your email as spam in their inbox provider. When Plunk receives that complaint, the contact is **always automatically unsubscribed** and Plunk fires an `email.complaint` event on the contact.

Complaints are taken more seriously than bounces by mail providers — even a small complaint rate can hurt your sender reputation and deliverability.

### Preventing complaints

* Ensure your emails are relevant and valuable to your audience.
* Include a clear, working unsubscribe link in every marketing email — Plunk injects this automatically for `MARKETING` template/campaign types.
* Monitor your email frequency to avoid overwhelming your contacts.
* Make sure recipients clearly opted in. Avoid scraped, purchased, or stale lists.