Cognito is an identity management service that enables developers to add user sign-up, sign-in, and access control to web and mobile applications. It is fully managed by AWS, which means it scales automatically to accommodate hundreds of thousands of users. Cognito supports a variety of standard identity protocols such as OAuth 2.0, SAML, and OpenID Connect.
The service integrates seamlessly with other AWS services, providing a secure and scalable user directory that can handle user data storage, authentication, and synchronization across multiple devices. With AWS Cognito, developers can focus on creating a smooth user experience without the complexity of building and managing a custom authentication system.
OAuth2 is an authorization framework that enables applications to obtain limited access to user accounts on an HTTP service, such as Facebook, GitHub, or Google. It works by delegating user authentication to the service that hosts the user account and authorizing third-party applications to access the user account.
OAuth2 specifies a process for resource owners to authorize third-party access without sharing their credentials, using different types of authorization grants (e.g., authorization code, implicit grant).
This framework simplifies developers’ work by providing a standardized way to securely authorize web, mobile, and desktop applications. It is designed with flexibility in mind, allowing it to be used for various types of applications including those running on smart devices.
User pools in AWS Cognito are managed directories that store user profile information and handle user authentication. They use OAuth 2.0 to provide a secure, standardized way to manage user access and authorization. OAuth 2.0 grants in user pools facilitate various authentication scenarios, ensuring seamless integration with different application types.
This grant type is designed for applications that can securely store client secrets. It works by exchanging an authorization code for tokens after the user has authenticated. Initially, the application redirects the user to the AWS Cognito login page. Upon successful authentication, AWS Cognito redirects back to the application with an authorization code. The application then exchanges this code at the token endpoint for an ID token, access token, and refresh token.
This method is considered more secure than other grant types because the tokens are transmitted directly to the application without passing through a user’s web browser, reducing the risk of interception. It is recommended when developing web applications that require high levels of security and access control.
The Implicit Grant type is primarily used for client-side applications where the application cannot securely store client secrets. This flow begins with the application directing the user to the AWS Cognito login page. After successful authentication, AWS Cognito redirects the user back to the application with an access token and, optionally, an ID token directly in the URL. These tokens are then used by the application to make requests on behalf of the user.
However, due to its inherent security weaknesses—such as exposing tokens in URLs which can be intercepted or leaked through browser history—the implicit grant is considered less secure than other types like authorization code grant. It’s mainly for scenarios where front-end applications require immediate access without server-side token handling capability.
This grant type is designed for server-to-server communication, where an application needs to access an API without user interaction. Unlike other OAuth 2.0 flows, it does not involve user authentication but authenticates the application itself to access its own resources or those of another service.
To implement this, the application makes a direct request to the AWS Cognito token endpoint with its credentials (client ID and client secret). Upon successful authentication, AWS Cognito issues an access token that the application can use to make API requests.
The Client Credentials Grant is useful for background services or processes that need to perform actions on behalf of themselves rather than acting on behalf of a user. The access token is limited to the application’s own resources, ensuring secure and appropriate access.
Implementing the Authorization Code Grant flow in AWS Cognito involves several steps. This method is suitable for applications that can securely store client secrets, providing a secure way to handle user authentication and obtain tokens.
Note: In order to run the example in this tutorial, you will need to set up a domain name, SSL certificate, and a minimal web application that implements a redirect URL.
Step 1: Initiate authorization request
The application starts the process by directing the user’s browser to the AWS Cognito authorization endpoint. The request includes:
Example request:
Step 2: User authentication
Paste the above URL in your browser, after filling in the missing info, to test your flow. You should be redirected to a Cognito-hosted login page, like this:
Click Sign up and the following dialog should appear:
Enter new credentials to create a user account:
You can then visit the authorization URL and enter the credentials.
Step 3: Authorization code grant
Upon successful authentication, AWS Cognito redirects the user back to the specified redirect_uri with an authorization code.
Example redirect:
Step 4: Exchange authorization code for tokens
The application exchanges the authorization code for tokens by making a POST request to the token endpoint. This request includes:
POST https://<AUTH_DOMAIN>/oauth2/token
Content-Type: application/x-www-form-urlencoded
grant_type=authorization_code&code=<AUTHORIZATION_CODE>&redirect_uri=<REDIRECT_URI>&client_id=<CLIENT_ID>&client_secret=<CLIENT_SECRET>
Step 5: Receive tokens
AWS Cognito responds with JSON containing the access token, ID token, refresh token, and other details.
Example response:
{
“access_token”: “ACCESS_TOKEN”,
“refresh_token”: “REFRESH_TOKEN”,
“id_token”: “ID_TOKEN”,
“expires_in”: 3600,
“token_type”: “Bearer”
}
Full example implementation
Below is a basic example of how to implement this flow using an HTTP library:
Best Practices
Here are some of the main limitations associated with AWS Cognito, shared by users on the G2 platform.
Implementing and managing AWS Cognito can be complex. Developers must understand concepts such as user pools, identity pools, OAuth 2.0 flows, and federation with external identity providers. This can pose challenges for teams without AWS expertise.
In addition, the setup process involves multiple steps across different AWS services, which can be time-consuming and requires attention to detail. Developers need to write custom code to interact with Cognito’s APIs for user authentication, token validation, and user session management. \
The available guides and reference materials often lack comprehensive examples, detailed explanations of complex features, or step-by-step instructions for specific use cases. The documentation does not always keep pace with the frequent updates and new features released by AWS, and developers may find themselves working with outdated information.
Developers often encounter limitations when trying to tailor the user experience or integrate more closely with their application’s branding. The user interface for sign-up, sign-in, and password recovery pages provided by AWS Cognito, for example, offers only basic customization capabilities.
While Cognito allows some level of customization through themes and custom CSS, the scope is limited and may not meet all design requirements. This can lead to a disjointed user experience that doesn’t fully align with the look and feel of the parent application.
Cognito supports basic customization options for the login and registration interfaces, such as logo changes and color adjustments. However, the flexibility to customize these interfaces to match an application’s unique branding and UI design is limited. This can result in a user experience that feels disconnected from the rest of the application.
Frontegg provides a robust and flexible platform for user authentication and authorization, positioning itself as a strong alternative to AWS Cognito. It offers a pre-configured hosted login that simplifies the integration process, allowing developers to quickly add secure login functionality to their applications with minimal code changes.
Frontegg’s hosted login is compliant with the OpenID Connect protocol, ensuring a standardized and secure authentication process. It supports various OAuth2.0 flows, making it adaptable to different application needs. The platform also emphasizes ease of use with intuitive configuration options through its portal, where developers can manage authentication settings, configure redirect URLs, and set up authorization codes.
Frontegg also enhances security through features like Proof Key for Code Exchange (PKCE), which provides additional protection for public clients such as single-page applications. The platform’s flexibility extends to customization, allowing seamless alignment with an application’s branding and user experience.
Learn more about Frontegg for authentication
