The toJSON() method of the PublicKeyCredential interface returns a JSON type representation of a PublicKeyCredential.

The properties of the returned object depend on whether the credential is returned by navigator.credentials.create() when creating a key pair and registering a user, or navigator.credentials.get() when authenticating a user.

This method is automatically invoked when web app code calls JSON.stringify() to serialize a PublicKeyCredential so that it can be sent to relying party server when registering or authenticating a user. It not intended to be called directly in web app code.

None.

A JSON type representation of a PublicKeyCredential object.

The included properties depend on whether the credential was returned by navigator.credentials.create() on registration, or navigator.credentials.get() when authenticating a user. The values and types of included properties are the same as for PublicKeyCredential, with the exception that base64url-encoded strings are used in place of buffer properties.

The object properties are:

id

The value returned by PublicKeyCredential.id.

rawId

A base64url-encoded version of PublicKeyCredential.rawId.

authenticatorAttachment Optional

The value returned by PublicKeyCredential.authenticatorAttachment.

type

The string "public-key".

clientExtensionResults

An array contaning base64url-encoded versions of the values returned by PublicKeyCredential.getClientExtensionResults().

response

The response property object depends on whether the credentials are returned following a registration or authentication operation.

• When registering a new user response will be a JSON-type representation of AuthenticatorAttestationResponse where buffer values have been base64url encoded.
• When authenticating a user the returned value will be a JSON-type representation version of AuthenticatorAssertionResponse where buffer values have been base64url encoded.

When registering a new user, a relying party server will supply information about the expected credentials to the web app. The web app calls navigator.credentials.create() with the received information (createCredentialOptions below), which returns a promise that fulfills with the new credential (a PublicKeyCredential).

const newCredentialInfo = await navigator.credentials.create({
  createCredentialOptions,
});

The web app then serializes the returned credential using JSON.stringify() (which in turn calls toJSON()) and posts it back to the server.

const registration_url = "https://example.com/registration";
const apiRegOptsResp = await fetch(registration_url, {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify(newCredentialInfo), //Calls newCredentialInfo.toJSON
});

• Web Authentication API
• PublicKeyCredential.parseCreationOptionsFromJSON()
• PublicKeyCredential.parseRequestOptionsFromJSON()