Get Cognito Token In Lambda, The latter is set up to authorize via a Cognito user pool authorizer. Amazon Cognito issues tokens that use some of the integrity and confidentiality features of the OpenID Connect (OIDC) specification. NET with Amazon Cognito Identity Provider. Cognito user pool stores users, hosts login UI, and issues JWT tokens. In this tutorial, we will focus on securing the API using a Lambda Authorizer with JSON Web Tokens (JWTs). How can I use the Cognito SDK with the Lambda function to fetch the JWT access token? I tried to create lambda function which is accessible through lambda function url and want to perform my own validation. 3. Cognito acts as the OAuth 2. The token endpoint returns tokens for app clients that support client credentials grants and authorization code grants. Amazon Cognito raises the Sync Trigger event when a dataset is synchronized. A group, claim, attribute, or role in an access or ID token meets the requirements that you define in a Lambda function. Use these credentials in Postman to test your Lambda function. What is a JWT Token? The Lambda authorizer looks up the Amazon Cognito group that the user belongs to in the JWT and does a lookup in Amazon DynamoDB to get the policy that’s mapped to the group. This article won’t go into the alternatives and other options out there but will specifically touch upon something that I know was a big question for me when I started with Cognito which was, “how can I customize the private claims in a token?”. But the access token stays unchanged. You can use the Sync Trigger event to take an action when a user updates data. User pool tokens indicate validity with objects like the expiration time, issuer, and digital signature. The Lambda authorizer code decodes and verifies the token, and its business logic determines whether the request should proceed to the backend or be denied. The pre token generation trigger is a Lambda function that Amazon Cognito sends a default set of claims to. But when I paste in the Access Token, I get 401 - unauthorized. Nov 13, 2025 · Learn how to use Amazon Cognito's Pre Token Generation Lambda Trigger to add custom claims directly to JWT tokens. Cognito User Pools: Implement user authentication and authorization with Amazon Cognito. 0 access tokens, OpenID Connect (OIDC) ID tokens, and refresh tokens. Exchange the JWT for temporary AWS credentials via a Cognito Identity Pool. In this story, we’ll explain how to add custom attributes in JWT ID Tokens using the Pre-Token Generation lambda trigger. it is cognito domain URL with the token path should be mentioned. Verify ID and access JWT tokens from AWS Cognito in your node/Lambda backend with minimal npm dependencies. Your app can exchange the code with the Token endpoint for access, ID, and refresh tokens. The lambda function is acting as a middleman to transfer requests from an IOT device to my own API. How can I get the identity id of the user (logged in by AWS Cognito) that invoked an AWS Lambda function? Do I have to use the SDK on the Lambda function to get the identity id? How do I use the access token customization feature? Amazon Cognito works with AWS Lambda functions to modify your user pool’s authentication behavior and end-user experience. g. February 4, 2026 Cognito › developerguide Common Amazon Cognito scenarios Amazon Cognito enables user authentication, access to back-end resources, AWS services via API Gateway, Lambda, identity pools, third-party IdPs, and AppSync resources. This token can be verified with CognitoJwtVerifier (if signed by Cognito) or JwtVerifier (if signed by another IDP), see the examples above. The ID token is valid and isn't expired. Learn how to implement fine-grained access control using access tokens and scopes and the cost implications of this approach. There also is the option of adding a Pre-authentication Lambda trigger to change the Id token. Implement customer identity and access management (CIAM) that scales to millions of users with Amazon Cognito, fully managed authentication service. When a user logs in using the shared UI for cognito on the frontend, they get an access token, id token and refresh token. CloudFront distribution delivers the content to the end-users and triggers Lambda@Edge functions. Use a client-specific framework to call the deployed API Gateway API and supply the appropriate token in the Authorization header. For more information, see Pre token generation Lambda trigger. Amazon Cognito Events allows you to execute an AWS Lambda function in response to important events in Amazon Cognito. In this section, you’ll learn how to configure a pre token generation Lambda trigger function and invoke it during the Amazon Cognito authentication process. custom_sms_sender - Configuration for a custom SMS sender Lambda function pre_token_generation_config - Configuration for a Lambda function that executes before token generation. However, I can't get the authorized user's identity in the Lambda function. lambda function lambda_arn - ARN of the Lambda function. You can also make direct REST API requests to Amazon Cognito user pools service endpoints. 0 authorization server. identity) as explained in the context Object Properties section of the Lambda Programming Model help topic. Sign up a user with Amazon Cognito. The access token authorizes users to retrieve information from access-protected resources like Amazon Cognito token-authorized API operations and third-party APIs. I want to use an Amazon Cognito user pool as the authentication method for my application. 2. Among these, access tokens play a 16 I have a Lambda function handling POST requests triggered by the API Gateway. Cognito access tokens are JSON Web Tokens (JWTs), and to simplify our coding, we might opt for an external package to handle token verification. When a user logs in to an AWS Cognito user pool, the system verifies their credentials and, upon successful authentication, issues ID, access, and refresh tokens. To get started with an Amazon Web Services SDK, see Tools to Build on Amazon Web Services. authorizer. Refresh tokens are encrypted user pool tokens that signal a request to Amazon Cognito for new ID and access tokens. Amazon API Gateway invokes an AWS Lambda function as a Lambda Authorizer. A very long-awaited Amazon Cognito feature was released a few months ago (December 2023): as per the title, Cognito now supports customisation of access tokens via a Lambda trigger! 1 I am trying to get a Cognito access token from a lambda function. And that's why I want to get user info using identitiy_id, Is there a way to get JWT token? Can I safely pass it to lambda function in the payload? I already created a User Pool in Amazon Cognito and now I want to fetch the JWT access token using an AWS Lambda function, but I don't know how to do this. Authorization works - if I pass a user's ID token, the request is processed, if I don't I get a 401. If the ID token is expired or is invalid, Cognito User Pool Authorizer will send Unauthorized (401) response to the caller. As you can read from their publication, you can get the claims from unexpired ID token of the authorization header. To generate an access token with custom scopes, you must request it through your user pool public endpoints. cognito_identity_id. 0 Authorization Code Flow. A practical guide to diagnosing and resolving NotAuthorizedException errors in AWS Cognito, covering wrong credentials, app client misconfigurations, and token issues. So far, I've spen Learn how to generate requests to the /oauth2/token endpoint for Amazon Cognito OAuth 2. x-amzn-oidc-data: user claims JWT signed by the ALB. Eliminate extra UserInfo endpoint calls and improve your ASP. Jun 23, 2016 · This idToken will get Validated by the Cognito Identity Pool via Coginito Authorizer (Used in Authorization Method dropdown). When making requests to backend services you're supposed to use the access token. js and AWS Lambda functions to send custom attributes to an Amazon Cognito user pool to inject additional context into identity tokens. Disclaimer: I'm the author of this. Customize Amazon Cognito user pool workflows with AWS Lambda triggers. Make sure verifier instance is shared across verifier. So far so good, as I should have what I need. Nov 18, 2025 · Authenticate a Cognito User Pool user and retrieve a JSON Web Token (JWT). Cognito delivers a unique identifier for each user and acts as an OpenID token Token Verification: The Lambda function reads the public key from AWS Cognito’s JWKS endpoint to verify the signature of the access token. Is there a way to configure Cognito to automatically add this custom claim/attribute to the JWT access token without using a pre-token generation Lambda function? Do you want to request a feature or report a bug? question Is it possible to get user attributes (like email) in a Lambda/cloud logic function. The best way that I've seen to get User Pool attributes within Lambda is to use a custom authorizer, pass in the JWT token generated client-side by the SDK, and decode it server-side. Configure a user pool to call a Lambda function for the PreSignUp trigger. (with a Authenticated request). I want a secure way to verify the ID and access tokens that clients send to my application. The Lambda function scans a DynamoDB table and automatically confirms known users. After authorizing the user and decoding the JWT token, your Lambda will be able to access the User Pool attributes in context. When invoked, I can get context. During the development process, working seamlessly with Cognito locally became essential, as relying solely I would like this "userType" claim/attribute to be included in the JWT access token whenever the user signs in or the token is refreshed. 0 scopes, user pool group membership, user attributes, and others You must ensure that your application is receiving the same token that Amazon Cognito issued. lambda config custom_email_sender - Configuration for a custom email sender Lambda function. The AWS Lambda function validates the access token and retrieves the Amazon Cognito user attributes, embedding them in the context. This ensures the token’s validity and integrity. As a security best practice, and to receive refresh tokens for your users, use an authorization code grant in your app. By the end, you’ll confidently generate and use short-lived credentials to validate Lambda behavior for authenticated users. identity. Build a complete backend for single-page applications on AWS with API Gateway, Lambda, Cognito authentication, DynamoDB, S3 file uploads, and WebSocket support. Recently, my company migrated from an in-house authentication system to Amazon Cognito. I am trying to pass the Cognito user information (e. I'm only getting the: Architecture The sample flow is as follows: Amazon Cognito authenticated user submits access token to Amazon API Gateway REST API. Clients authenticate with Cognito to get tokens, then pass those tokens to API Gateway. Amazon Cognito Identity Provider SDK examples demonstrate authenticating users, setting up multi-factor authentication, signing up new users, confirming sign-ups, associating MFA applications, initiating authentication challenges, responding to challenges, verifying software tokens, deleting users, and resending confirmation codes. Verifier instance you get from verifierFactory() call has an internal JWKS cache to avoid hitting the network on subsequent calls. verify Use the Amazon Cognito CLI/SDK or API to sign a user in to the chosen user pool, and obtain an identity token or access token. With event versions two and three of the pre token generation Lambda trigger, you can customize the content of an access token from your user pool. May 26, 2024 · Go to Authorization and select Oauth 2. the flow more or less will be like this flow expected For the first Lambda After days of trial and error, I finally managed to get signin/signup working in VueJS with AWS Cognito. Example workflow: User -> AWS Cognito Identity Pool -> Temporary IAM Role -> Lambda Function Using this setup, the validateToken Lambda function validates tokens and returns authorization responses for requested resources. I am giving access to a user to invoke a single lambda function. Hello, I am using a Cognito user pool authorizer in my REST API. This comprehensive guide delves into the process of customizing access tokens within Amazon Cognito user pools, using AWS Lambda for dynamic authentication. . idToken getting generated by SDK can be done using another lambda+endpoint like login endpoint or it can be generated using cognito mobile sdk's as well. username, user group) from the API Gateway to a Lambda function, i With Amazon Cognito, the access token is referred to as an ID token, and it’s valid for 60 minutes. AWS SDK: Enables Lambda invocation from a browser or application. Using Amazon Cognito Federated Identities, you can enable authentication with one or more third-party identity providers (Facebook, Google, or Login with Amazon) or an Amazon Cognito user pool, and you can also choose to support unauthenticated access from your app. The following links can get you started with the CognitoIdentityProvider client in supported Amazon Web Services SDKs. claims. Lambda@Edge functions check if the request contains a cookie with a valid JWT token and implement a tiny backend to implement the OAuth 2. To learn more about using the SDKs, see Code examples for Amazon Cognito using AWS SDKs. Apr 3, 2025 · The Lambda authorizer code decodes and verifies the token, and its business logic determines whether the request should proceed to the backend or be denied. NET Core application performance. cognito-jwt-verifier is a tiny npm package to verify ID and access JWT tokens obtained from AWS Cognito in your node/Lambda backend with minimal dependencies. In a Pre token generation Lambda trigger, you can add, modify, and suppress token claims. The Architecture Here's how the pieces fit together. Authentication session flow duration Depending on the features of your user pool, you can end up responding to several challenges to InitiateAuth and RespondToAuthChallenge before your app retrieves tokens from Amazon Cognito. Scenarios Automatically confirm known users with a Lambda functionAutomatically migrate known users with a Lambda functionSign up a user with a user pool that requires MFAUse Amazon Cognito identity poolsWrite custom activity data with a Lambda function after Amazon Cognito user authentication Automatically confirm known users with a Lambda The following code examples show you how to perform actions and implement common scenarios by using the AWS SDK for . I have an idToken and accessToken and would like to pass that on to my Lambda function. This is where I've run into difficulties - using the test function on the API Gateway Cognito User Pool Authorizer console, I can paste in the ID token and it passes (decoding the token on-screen). API Gateway validates the token against Cognito and forwards the request to your Lambda backend if the token checks out. With the Essentials or Plus feature plan, you can also implement a pre token generation Lambda trigger that adds scopes to your access tokens at runtime. How to pass cognito authentication token in the headers through api gateway to a lambda function Asked 5 years ago Modified 3 years, 7 months ago Viewed 5k times Ultimately, I need to generate an AccessKeyId, SecurityKey and SessionToken for a user in a Cognito User Pool so that I can test a lambda function as a cognito user using Postman. An authorization code grant is a code parameter that Amazon Cognito appends to your redirect URL. To build the architecture described above, we will need a Cognito User Pool, Cognito App Client and a Pre Token Generation Lambda Trigger to add custom claims to Id Token. Lambda Authorizers: Use a custom Lambda function to validate authorization logic before allowing access. Nov 18, 2025 · By attaching Lambda triggers at key points, for example, before a user signs up, during authentication, and after tokens are issued, you can override default Cognito behaviour and introduce custom logic into the flow. Learn how to use Node. Customizing tokens You can customize the access and ID tokens that Amazon Cognito passes to your app. 0 and Cognito Details, dont forgot to to add correct URL in Access Token URL. In order for the API to accept the request, my lambda function needs to send a valid Cognito access token to the API. The claims include OAuth 2. 5 You can get the Cognito Identity ID from the identity property of the context parameter (context. Amazon Cognito includes a session string in the response to each request. Sign in as the new user, then clean up resources. When you pass an ID token to an Amazon Cognito authorizer, you can perform additional validation of the ID token contents on your application server. The Python code uses python-jose to handle the JWT token decoding and signature verification; that library must be included in the Lambda deployment package using one of the methods discussed in the Deployment Package in Python section of the AWS Lambda Developer Guide. cefr, wmewtb, jojx5, udum, nqvmrt, os90o, avvp, ddtj8e, gpez, oraxk,