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

# WebauthnStamper

## Introduction

The [`@turnkey/webauthn-stamper`](https://www.npmjs.com/package/@turnkey/webauthn-stamper) package is used for stamping requests made to Turnkey's API with WebAuthn credentials, but specifically for use with passkeys.

For more information on passkeys and WebAuthn refer to [this section](/authentication/passkeys/introduction).

## Installing

To get started install the [`@turnkey/webauthn-stamper`](https://www.npmjs.com/package/@turnkey/webauthn-stamper) client.

<CodeGroup>
  ```bash npm theme={"system"}
  npm i @turnkey/webauthn-stamper
  ```

  ```bash pnpm theme={"system"}
  pnpm i @turnkey/webauthn-stamper
  ```

  ```bash yarn theme={"system"}
  yarn add @turnkey/webauthn-stamper
  ```
</CodeGroup>

## Initializing

The `WebauthnStamper` class is a utility designed to facilitate the process of creating a digital stamp using WebAuthn credentials. This stamp is essential for authenticating requests made to a web server or API that utilizes WebAuthn for secure, passwordless authentication. You can initialize a new `WebauthnStamper` using the WebauthnStamper constructor:

### `constructor(config: TWebauthnStamperConfig): WebauthnStamper`

#### Parameters

<ParamField body="config" type="TWebauthnStamperConfig" required>
  An object containing configuration settings for the stamper.
</ParamField>

<ParamField body="rpId" type="string" required>
  The RPID ("Relying Party ID") for your origin. For an origin named `https://www.example.com`, the RPID is typically `example.com`. If you're testing on localhost, the RPID should be `localhost`.
</ParamField>

<ParamField body="timeout" type="number">
  The time in milliseconds before the stamp request times out. Defaults to 300000 milliseconds (5 minutes) if not specified.
</ParamField>

<ParamField body="userVerification" type="UserVerificationRequirement">
  Specifies the user verification requirements. Can be set to values like `required`, `preferred`, or `discouraged`. Defaults to `preferred` if not provided.
</ParamField>

<ParamField body="allowCredentials" type="PublicKeyCredentialDescriptor[]">
  An array of credential descriptors specifying the credentials to be allowed during authentication. This is optional and defaults to an empty array.
</ParamField>

#### Types

##### `TWebauthnStamperConfig`

```js theme={"system"}
type TWebauthnStamperConfig = {
  rpId: string;
  timeout?: number;
  userVerification?: UserVerificationRequirement;
  allowCredentials?: PublicKeyCredentialDescriptor[];
};
```

##### `UserVerificationRequirement`

```js theme={"system"}
type UserVerificationRequirement = "discouraged" | "preferred" | "required";
```

Refer to our guide on [using passkeys](/authentication/passkeys/options#userverification) for more information on this type and its usage.

##### `PublicKeyCredentialDescriptor`

```js theme={"system"}
interface PublicKeyCredentialDescriptor {
  id: BufferSource;
  transports?: AuthenticatorTransport[];
  type: PublicKeyCredentialType;
}
```

Refer to our guide on [using passkeys](/authentication/passkeys/options#allowcredentials) for more information on this type and its usage.

#### Example

```js theme={"system"}
import { WebauthnStamper } from "@turnkey/webauthn-stamper";
import { TurnkeyClient } from "@turnkey/http";

const stamper = new WebAuthnStamper({
  rpId: "example.com",
});

// New HTTP client able to sign with passkeys!
const httpClient = new TurnkeyClient(
  { baseUrl: "https://api.turnkey.com" },
  stamper,
);
```

## Methods

### `stamp: (input: string) => Promise<TStamp>`

Creates a digital stamp, which includes the public key, signature scheme, and a signature based on WebAuthn credentials.

#### Parameters

<ParamField body="input" type="string" required>
  The Turnkey activity request, or query to be sent to Turnkey's API.
</ParamField>

#### Types

##### `TStamp`

```js theme={"system"}
type TStamp = {
  stampHeaderName: string;
  stampHeaderValue: string;
};
```