# External User ID

### Introduction

An external user is your way to set a custom username in Keyless, allowing you to represent Keyless users with an identifier that is more familiar to your business such as a Unique identifier, GUID or UUID. Customers are explicitly advised not to input pii in this field (i.e. custom usernames, names or email addresses).

{% hint style="success" %}
For customers using the Authentication Service (which supports IDV Bridge SaaS and WebSDK), the External User ID documented on this page is mapped automatically to the Username in that service and vice-versa for ease of use.
{% endhint %}

{% openapi src="<https://424053338-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-MCDr5oxGulTybKzhddo%2Fuploads%2Fgit-blob-80f0c096b523cb6a0d6ab1982fa047b165259269%2Fswagger-operations-service.yaml?alt=media>" path="/users/{userId}/external-user" method="post" %}
[swagger-operations-service.yaml](https://424053338-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-MCDr5oxGulTybKzhddo%2Fuploads%2Fgit-blob-80f0c096b523cb6a0d6ab1982fa047b165259269%2Fswagger-operations-service.yaml?alt=media)
{% endopenapi %}

{% openapi src="<https://424053338-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-MCDr5oxGulTybKzhddo%2Fuploads%2Fgit-blob-80f0c096b523cb6a0d6ab1982fa047b165259269%2Fswagger-operations-service.yaml?alt=media>" path="/users/{userId}/external-user" method="patch" %}
[swagger-operations-service.yaml](https://424053338-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-MCDr5oxGulTybKzhddo%2Fuploads%2Fgit-blob-80f0c096b523cb6a0d6ab1982fa047b165259269%2Fswagger-operations-service.yaml?alt=media)
{% endopenapi %}

{% openapi src="<https://424053338-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-MCDr5oxGulTybKzhddo%2Fuploads%2Fgit-blob-80f0c096b523cb6a0d6ab1982fa047b165259269%2Fswagger-operations-service.yaml?alt=media>" path="/external-users/{externalUserId}" method="delete" %}
[swagger-operations-service.yaml](https://424053338-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-MCDr5oxGulTybKzhddo%2Fuploads%2Fgit-blob-80f0c096b523cb6a0d6ab1982fa047b165259269%2Fswagger-operations-service.yaml?alt=media)
{% endopenapi %}

{% openapi src="<https://424053338-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-MCDr5oxGulTybKzhddo%2Fuploads%2Fgit-blob-80f0c096b523cb6a0d6ab1982fa047b165259269%2Fswagger-operations-service.yaml?alt=media>" path="/external-users/{externalUserId}/users" method="get" %}
[swagger-operations-service.yaml](https://424053338-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-MCDr5oxGulTybKzhddo%2Fuploads%2Fgit-blob-80f0c096b523cb6a0d6ab1982fa047b165259269%2Fswagger-operations-service.yaml?alt=media)
{% endopenapi %}