Nocturnal Pumpkin Maelstrom


    1.0.1 • Public • Published


    Credential Handler API utility functions for Web applications


    This module provides some plumbing that makes writing a Credential Handler easier.

    A Credential Handler is an event handler for credential request and credential storage events. The Credential Handler API helps solve the Nascar Problem. The Credential Handler API enables websites to install Credential Handlers that can respond when users visit other websites that request or store credentials.

    For example, a user may visit a website that wants them to login using OpenIdConnect, provide an OAuth Token, authenticate using a DID, or present some Verifiable Credentials. When these other websites use the Credential Handler API, the user is shown an in-browser selection screen with visual representations (e.g. icons and origin information) of only those Credential Handlers that they have been previously installed by the user and that are compatible with the website's request. Once the user makes a choice, the appropriate Credential Handler is loaded and a credential event is sent to it.

    The Credential Handler receives the event via a Service Worker or, if the Credential Handler Polyfill is used, a simple page with no UI elements is loaded that uses the polyfill to receive and respond to the event.

    The Credential Handler must respond to the event with a credential that fulfills the request. If necessary, the Credential Handler may open a window on its website's origin to allow the user to interact with its website prior to responding. This UI can be styled and shaped according to the website owner's brand using arbitrary JavaScript and HTML like any other webpage.

    This module provides utility functions to handle installing/uninstalling a Credential Handler, receiving an event, responding to an event, and forwarding an event to another window for handling after user interaction with a UI.

    Without this module, a developer must setup this basic infrastructure to handle credential requests and credential storage requests and their interaction with a UI window on their own.

    See also:


    To install locally (for development):

    git clone
    cd web-credential-handler
    npm install

    To install as a dependency of another project, add this to your package.json:

    "web-credential-handler": "^1.0.0"


    Requiring web-credential-handler (browser)


    import {installHandler, activateHandler} from 'web-credential-handler';

    Installing a Credential Handler

    import {installHandler} from 'web-credential-handler';

    Uninstalling a Credential Handler


    import {uninstallHandler} from 'web-credential-handler';

    Activating a Credential Handler


    import {activateHandler} from 'web-credential-handler';

    Receiving a credential event in a UI window


    import {receiveCredentialEvent} from 'web-credential-handler';

    Getting a Credential Handler Registration


    import {getHandlerRegistration} from 'web-credential-handler';


    PRs accepted.

    Small note: If editing the Readme, please conform to the standard-readme specification.

    Commercial Support

    Commercial support for this library is available upon request from Digital Bazaar:


    New BSD License (3-clause) © Digital Bazaar




    npm i web-credential-handler

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    • davidlehn
    • codenamedmitri
    • msporny
    • dlongley
    • gannan