# Web

## Complete Guides

#### Sign in with Email/Phone Number

Authenticate users by sending a Magic Link or OTP via email, SMS, or WhatsApp

{% content-ref url="/pages/-M0ROJn7tosL9qeumqFd" %}
[Sign In with Email/Phone Number](/sdk-reference/web/web-sdk-verify-email-phone.md)
{% endcontent-ref %}

#### Sign in with WebAuthn

Authenticate users using TouchID or Windows Hello from your website.

{% content-ref url="/pages/-MCk3X5Dh4Fkxp20D4Rt" %}
[Sign In with WebAuthn](/sdk-reference/web/sign-in-with-webauthn.md)
{% endcontent-ref %}

#### Sign in with Device

If you have **mobile app**, you can ask the user to approve the login request from their phone.

{% content-ref url="/pages/-M3o-GTINgCweb4ATz-9" %}
[Sign In with Device](/sdk-reference/web/web-sdk-passwordless-login.md)
{% endcontent-ref %}

## Quickstart Guides

{% content-ref url="/pages/-MBpqtdlR54h41rVFGWy" %}
[React – Sign in with Email/Phone](/quickstart-guides/react-magic-link-with-email-and-phone.md)
{% endcontent-ref %}

{% content-ref url="/pages/-MAUbWpO8XONhF-vdxAG" %}
[HTML – Sign in with Email/Phone](/quickstart-guides/html-magic-link-with-email-and-phone.md)
{% endcontent-ref %}

{% content-ref url="/pages/-MCjwlfkbi3ejQQ0qQ4K" %}
[React – WebAuthn](/quickstart-guides/react-webauthn.md)
{% endcontent-ref %}


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# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://docs.cotter.app/sdk-reference/web.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.