# Email a sign-in link (/api/customers/send-customer-link)

`POST https://api.comecero.com/api/v1/customers/send_link`

Emails a customer a link that signs them in to your app without a password, for example to see past orders and downloads. The customer is found by email address. When several customers of the account have that email, the newest gets the link and the email offers the others too (up to 10). The link opens `https://<your app host>/link` and works for 4 hours. The account needs an app host in its technical settings and a notification set up for customer links, or the call fails with `422`. No token is needed. Every input is in the query string; there is no body.

## Parameters

- `account_id` (query, required): The account the customer belongs to.
- `app_id` (query, required): The id of an app installed on the account. The link signs the customer in to it.
- `email` (query, required): The customer's email address. Must match a customer's email exactly (not case sensitive).
- `redirect_uri` (query): A relative path in the app to open after sign-in, for example `/orders`. A full URL with `https://` is a `400`.
- `test` (query): `true` to look up a test customer.
- `date_start` (query): Only consider customers created on or after this date (ISO 8601).
- `date_end` (query): Only consider customers created on or before this date (ISO 8601).
- `date_type` (query): Which customer date `date_start` and `date_end` use.

Responses: 204, 400, 422.

Full schemas: operation `send_customer_link` in /openapi.json.