> ## Documentation Index
> Fetch the complete documentation index at: https://docs.lekalao.com/llms.txt
> Use this file to discover all available pages before exploring further.

# List hygiene

> Addresses looked at before they cost a bounce, and readers who stopped reading left in peace.

Receivers judge a sender by two things above all: how often it writes to addresses that do not exist, and what its readers do with what they receive. Lekalao works on both without being asked.

## Addresses, looked at on the way in

Someone **new** to a list is looked at before they are let in — from a form, the API or an import alike. Whoever is already on the list is never judged again.

| What is found                                       | What happens                                                                                    |
| --------------------------------------------------- | ----------------------------------------------------------------------------------------------- |
| A **throwaway** mailbox (yopmail, mailinator…)      | Refused: "… is a throwaway address. Use one you read."                                          |
| A domain with **no mail server**                    | Refused: "… cannot receive e-mail: its domain has no mail server."                              |
| …that looks like a slip of the finger (`gmial.com`) | Refused, with what was very likely meant: "Did you mean [ada@gmail.com](mailto:ada@gmail.com)?" |
| An address a team reads (`info@`, `contact@`)       | Let in, and known as such.                                                                      |

A form tells the person there and then, while they can still fix it. The API answers `422` with the reason and the suggestion. An import counts the row in error and brings the others in.

The mail server is the judge: a domain that *looks* mistyped but does receive e-mail is somebody's domain, and is let in. And when the DNS does not answer at all, nobody is turned away: a resolver's bad minute is not a reason to lose a subscriber.

## Readers who stopped reading

Writing month after month to people who never open is how a domain earns the spam folder for everybody else on the list. In the list's **Settings**:

<ParamField path="Stop writing after this many days without an open" type="days, 30 to 1825">
  Empty: never. With a number, someone who was sent **at least five e-mails** over that time and opened or clicked none is **left in peace**: campaigns no longer go to them.
</ParamField>

They are **still subscribed** — they said nothing of the kind — and nothing about them is deleted. Their record says **Left in peace since…**, and the settings say how many are in that case today.

**The first sign of life wakes them**: an open by a person, a click, or filling in your form again. They are written to again from the next campaign.

<Note>
  Apple's Mail opens e-mails on behalf of its users and hides whether they looked. Such an open wakes nobody — it is no proof of a reader — but nobody is left in peace on it either: it is no proof of an absence. Being wrong that way costs an e-mail; being wrong the other way costs a reader. See [About opens](/campaigns/statistics#about-opens).
</Note>