PublicKeyCredential: authenticatorAttachment property

Baseline 2023
Newly available

Since November 2023, this feature works across the latest devices and browser versions. This feature might not work in older devices or browsers.

Secure context: This feature is available only in secure contexts (HTTPS), in some or all supporting browsers.

The authenticatorAttachment read-only property of the PublicKeyCredential interface is a string that indicates the general category of authenticator used during the associated navigator.credentials.create() or navigator.credentials.get() call.

Value

A string, which will be one of the following values:

"platform"

The authenticator is part of the device WebAuthn is running on (termed a platform authenticator), therefore WebAuthn will communicate with it using a transport available to that platform, such as a platform-specific API. A public key credential bound to a platform authenticator is called a platform credential.

"cross-platform"

The authenticator is not a part of the device WebAuthn is running on (termed a roaming authenticator as it can roam between different devices), therefore WebAuthn will communicate with it using a cross-platform transport protocol such as Bluetooth or NFC. A public key credential bound to a roaming authenticator is called a roaming credential.

Examples

js
const options = {
  challenge: new Uint8Array(26) /* from the server */,
  rp: {
    name: "Example CORP",
    id: "login.example.com",
  },
  user: {
    id: new Uint8Array(26) /* To be changed for each user */,
    name: "canand@example.com",
    displayName: "Carina Anand",
  },
  pubKeyCredParams: [
    {
      type: "public-key",
      alg: -7,
    },
  ],
};

navigator.credentials
  .create({ publicKey: options })
  .then((pubKeyCredential) => {
    const attachment = pubKeyCredential.authenticatorAttachment;
    // Do something with authenticatorAttachment
  })
  .catch((err) => {
    // Deal with any error
  });

Specifications

Specification
Web Authentication: An API for accessing Public Key Credentials - Level 3
# dom-publickeycredential-authenticatorattachment

Browser compatibility