better-auth/docs/content/docs/plugins/passkey.mdx

---
title: Passkey
description: Passkey
---

Passkeys are a secure, passwordless authentication method using cryptographic key pairs, supported by WebAuthn and FIDO2 standards in web browsers. They replace passwords with unique key pairs: a private key stored on the user's device and a public key shared with the website. Users can log in using biometrics, PINs, or security keys, providing strong, phishing-resistant authentication without traditional passwords.

The passkey plugin implementation is powered by [SimpleWebAuthn](https://simplewebauthn.dev/) behind the scenes.

## Installation

<Steps>
    <Step>
        ### Add the plugin to your auth config
        To add the passkey plugin to your auth config, you need to import the plugin and pass it to the `plugins` option of the auth instance.

        **Options**

        `rpID`: A unique identifier for your website. 'localhost' is okay for local dev

        `rpName`: Human-readable title for your website

        `origin`: The URL at which registrations and authentications should occur. `http://localhost` and `http://localhost:PORT` are also valid. Do **NOT** include any trailing /

        `authenticatorSelection`: Allows customization of WebAuthn authenticator selection criteria. Leave unspecified for default settings.
            - `authenticatorAttachment`: Specifies the type of authenticator
                - `platform`: Authenticator is attached to the platform (e.g., fingerprint reader)
                - `cross-platform`: Authenticator is not attached to the platform (e.g., security key)
                - Default: `not set` (both platform and cross-platform allowed, with platform preferred)
            - `residentKey`: Determines credential storage behavior.
                - `required`: User MUST store credentials on the authenticator (highest security)
                - `preferred`: Encourages credential storage but not mandatory
                - `discouraged`: No credential storage required (fastest experience)
                - Default: `preferred`
            - `userVerification`: Controls biometric/PIN verification during authentication:
                - `required`: User MUST verify identity (highest security)
                - `preferred`: Verification encouraged but not mandatory
                - `discouraged`: No verification required (fastest experience)
                - Default: `preferred`
            
           
        ```ts title="auth.ts"
        import { betterAuth } from "better-auth"
        import { passkey } from "better-auth/plugins/passkey" // [!code highlight]

        export const auth = betterAuth({
            plugins: [ // [!code highlight]
                passkey(), // [!code highlight]
            ], // [!code highlight]
        })
        ```
    </Step>
      <Step>
        ### Migrate the database

        Run the migration or generate the schema to add the necessary fields and tables to the database.

        <Tabs items={["migrate", "generate"]}>
            <Tab value="migrate">
            ```bash
            npx @better-auth/cli migrate
            ```
            </Tab>
            <Tab value="generate">
            ```bash
            npx @better-auth/cli generate
            ```
            </Tab>
        </Tabs>
        See the [Schema](#schema) section to add the fields manually.
    </Step>
    <Step>
        ### Add the client plugin

        ```ts title="auth-client.ts"
        import { createAuthClient } from "better-auth/client"
        import { passkeyClient } from "better-auth/client/plugins"

        export const authClient = createAuthClient({
            plugins: [ // [!code highlight]
                passkeyClient() // [!code highlight]
            ] // [!code highlight]
        })
        ```
    </Step>

</Steps>

## Usage

### Add/Register a passkey

To add or register a passkey make sure a user is authenticated and then call the `passkey.addPasskey` function provided by the client.

```ts
// Default behavior allows both platform and cross-platform passkeys
const { data, error } = await authClient.passkey.addPasskey();
```

This will prompt the user to register a passkey. And it'll add the passkey to the user's account.

You can also specify the type of authenticator you want to register. The `authenticatorAttachment` can be either `platform` or `cross-platform`.

```ts
// Register a cross-platform passkey showing only a QR code
// for the user to scan as well as the option to plug in a security key
const { data, error } = await authClient.passkey.addPasskey({
  authenticatorAttachment: 'cross-platform'
});
```

### Sign in with a passkey

To sign in with a passkey you can use the passkeySignIn method. This will prompt the user to sign in with their passkey.

Signin method accepts:

`autoFill`: Browser autofill, a.k.a. Conditional UI. [read more](https://simplewebauthn.dev/docs/packages/browser#browser-autofill-aka-conditional-ui)

`email`: The email of the user to sign in.

`fetchOptions`: Fetch options to pass to the fetch request.

```ts
const data = await authClient.signIn.passkey();
```

### Conditional UI

The plugin supports conditional UI, which allows the browser to autofill the passkey if the user has already registered a passkey.

There are two requirements for conditional UI to work:

<Steps>
    <Step>
        #### Update input fields

        Add the `autocomplete` attribute with the value `webauthn` to your input fields. You can add this attribute to multiple input fields, but at least one is required for conditional UI to work.

        The `webauthn` value should also be the last entry of the `autocomplete` attribute.

        ```html
        <label for="name">Username:</label>
        <input type="text" name="name" autocomplete="username webauthn">
        <label for="password">Password:</label>
        <input type="password" name="password" autocomplete="current-password webauthn">
        ```
    </Step>
    <Step>
        #### Preload the passkeys

        When your component mounts, you can preload the user's passkeys by calling the `authClient.signIn.passkey` method with the `autoFill` option set to `true`.

        To prevent unnecessary calls, we will also add a check to see if the browser supports conditional UI.

        <Tabs items={["React"]}>
            <Tab value="React">
            ```ts
            useEffect(() => {
               if (!PublicKeyCredential.isConditionalMediationAvailable ||
                   !PublicKeyCredential.isConditionalMediationAvailable()) {
                 return;
               }

              void authClient.signIn.passkey({ autoFill: true })
            }, [])
            ```
            </Tab>
        </Tabs>

    </Step>

   </Steps>

Depending on the browser, a prompt will appear to autofill the passkey. If the user has multiple passkeys, they can select the one they want to use.

Some browsers also require the user to first interact with the input field before the autofill prompt appears.

### Debugging

To test your passkey implementation you can use [emulated authenticators](https://developer.chrome.com/docs/devtools/webauthn). This way you can test the registration and sign-in process without even owning a physical device.

## Schema

The plugin require a new table in the database to store passkey data.

Table Name: `passkey`

<DatabaseTable
    fields={[
        { 
            name: "id", 
            type: "string", 
            description: "Unique identifier for each passkey",
            isPrimaryKey: true
        },
        {
            name: "name",
            type: "string",
            description: "The name of the passkey",
            isOptional: true
        },
        { 
            name: "publicKey", 
            type: "string", 
            description: "The public key of the passkey",
        },
        { 
            name: "userId", 
            type: "string", 
            description: "The ID of the user",
            isForeignKey: true
        },
        {
            name: "credentialID",
            type: "string",
            description: "The unique identifier of the registered credential",
        },
        { 
            name: "counter", 
            type: "number", 
            description: "The counter of the passkey",
        },
        {
            name: "deviceType",
            type: "string",
            description: "The type of device used to register the passkey",
        },
        {
            name: "backedUp",
            type: "boolean",
            description: "Whether the passkey is backed up",
        },
        {
            name: "transports",
            type: "string",
            description: "The transports used to register the passkey",
        },
        { 
            name: "createdAt", 
            type: "Date", 
            description: "The time when the passkey was created",
        },
        {
                name: "aaguid",
                type: "string",
                description: "Authenticator's Attestation GUID indicating the type of the authenticator",
                isOptional: true
        },
    ]}
    />

## Options

**rpID**: A unique identifier for your website. 'localhost' is okay for local dev.

**rpName**: Human-readable title for your website.

**origin**: The URL at which registrations and authentications should occur. `http://localhost` and `http://localhost:PORT` are also valid. Do NOT include any trailing /.

**authenticatorSelection**: Allows customization of WebAuthn authenticator selection criteria. When unspecified, both platform and cross-platform authenticators are allowed with `preferred` settings for `residentKey` and `userVerification`.

**aaguid**: (optional) Authenticator Attestation GUID. This is a unique identifier for the passkey provider (device or authenticator type) and can be used to identify the type of passkey device used during registration or authentication.