cognito

name	cognito
description	AWS Cognito user authentication and authorization service. Use when setting up user pools, configuring identity pools, implementing OAuth flows, managing user attributes, or integrating with social identity providers.
metadata	{"category":"development","source":{"repository":"https://github.com/itsmostafa/aws-agent-skills","path":"skills/cognito","license_path":"LICENSE","commit":"4ab904a69cda893b5c98f97966bf9a48311823e9"}}

AWS Cognito

Amazon Cognito provides authentication, authorization, and user management for web and mobile applications. Users can sign in directly or through federated identity providers.

Table of Contents

• Core Concepts
• Common Patterns
• CLI Reference
• Best Practices
• Troubleshooting
• References

Core Concepts

User Pools

User directory for sign-up and sign-in. Provides:

• User registration and authentication
• OAuth 2.0 / OpenID Connect tokens
• MFA and password policies
• Customizable UI and flows

Identity Pools (Federated Identities)

Provide temporary AWS credentials to access AWS services. Users can be:

• Cognito User Pool users
• Social identity (Google, Facebook, Apple)
• SAML/OIDC enterprise identity
• Anonymous guests

Tokens

Token	Purpose	Lifetime
ID Token	User identity claims	1 hour
Access Token	API authorization	1 hour
Refresh Token	Get new ID/Access tokens	30 days (configurable)

Common Patterns

Create User Pool

AWS CLI:

aws cognito-idp create-user-pool \
  --pool-name my-app-users \
  --policies '{
    "PasswordPolicy": {
      "MinimumLength": 12,
      "RequireUppercase": true,
      "RequireLowercase": true,
      "RequireNumbers": true,
      "RequireSymbols": true
    }
  }' \
  --auto-verified-attributes email \
  --username-attributes email \
  --mfa-configuration OPTIONAL \
  --user-attribute-update-settings '{
    "AttributesRequireVerificationBeforeUpdate": ["email"]
  }'

Create App Client

aws cognito-idp create-user-pool-client \
  --user-pool-id us-east-1_abc123 \
  --client-name my-web-app \
  --generate-secret \
  --explicit-auth-flows ALLOW_USER_SRP_AUTH ALLOW_REFRESH_TOKEN_AUTH \
  --supported-identity-providers COGNITO \
  --callback-urls https://myapp.com/callback \
  --logout-urls https://myapp.com/logout \
  --allowed-o-auth-flows code \
  --allowed-o-auth-scopes openid email profile \
  --allowed-o-auth-flows-user-pool-client \
  --access-token-validity 60 \
  --id-token-validity 60 \
  --refresh-token-validity 30 \
  --token-validity-units '{
    "AccessToken": "minutes",
    "IdToken": "minutes",
    "RefreshToken": "days"
  }'

Sign Up User

import boto3
import hmac
import hashlib
import base64

cognito = boto3.client('cognito-idp')

def get_secret_hash(username, client_id, client_secret):
    message = username + client_id
    dig = hmac.new(
        client_secret.encode('utf-8'),
        message.encode('utf-8'),
        digestmod=hashlib.sha256
    ).digest()
    return base64.b64encode(dig).decode()

import os

username = '[e-mail]'
client_id = os.environ['COGNITO_CLIENT_ID']
client_secret = os.environ['COGNITO_CLIENT_SECRET']

response = cognito.sign_up(
    ClientId=client_id,
    SecretHash=get_secret_hash(username, client_id, client_secret),
    Username=username,
    Password=os.environ['COGNITO_INITIAL_PASSWORD'],
    UserAttributes=[
        {'Name': 'email', 'Value': username},
        {'Name': 'name', 'Value': 'Example User'}
    ]
)

Confirm Sign Up

cognito.confirm_sign_up(
    ClientId='client-id',
    SecretHash=get_secret_hash('[e-mail]', 'client-id', 'client-secret'),
    Username='[e-mail]',
    ConfirmationCode='123456'
)

Authenticate User

response = cognito.initiate_auth(
    ClientId='client-id',
    AuthFlow='USER_SRP_AUTH',
    AuthParameters={
        'USERNAME': '[e-mail]',
        'SECRET_HASH': get_secret_hash('[e-mail]', 'client-id', 'client-secret'),
        'SRP_A': srp_a  # From SRP library
    }
)

# For simple password auth (not recommended for production)
response = cognito.admin_initiate_auth(
    UserPoolId='us-east-1_abc123',
    ClientId='client-id',
    AuthFlow='ADMIN_USER_PASSWORD_AUTH',
    AuthParameters={
        'USERNAME': '[e-mail]',
        'PASSWORD': 'password',
        'SECRET_HASH': get_secret_hash('[e-mail]', 'client-id', 'client-secret')
    }
)

tokens = response['AuthenticationResult']
id_token = tokens['IdToken']
access_token = tokens['AccessToken']
refresh_token = tokens['RefreshToken']

Refresh Tokens

response = cognito.initiate_auth(
    ClientId='client-id',
    AuthFlow='REFRESH_TOKEN_AUTH',
    AuthParameters={
        'REFRESH_TOKEN': refresh_token,
        'SECRET_HASH': get_secret_hash('[e-mail]', 'client-id', 'client-secret')
    }
)

Create Identity Pool

aws cognito-identity create-identity-pool \
  --identity-pool-name my-app-identities \
  --allow-unauthenticated-identities \
  --cognito-identity-providers \
    ProviderName=cognito-idp.us-east-1.amazonaws.com/us-east-1_abc123,\
ClientId=client-id,\
ServerSideTokenCheck=true

Get AWS Credentials

import boto3

cognito_identity = boto3.client('cognito-identity')

# Get identity ID
response = cognito_identity.get_id(
    IdentityPoolId='us-east-1:12345678-1234-1234-1234-123456789012',
    Logins={
        'cognito-idp.us-east-1.amazonaws.com/us-east-1_abc123': id_token
    }
)
identity_id = response['IdentityId']

# Get credentials
response = cognito_identity.get_credentials_for_identity(
    IdentityId=identity_id,
    Logins={
        'cognito-idp.us-east-1.amazonaws.com/us-east-1_abc123': id_token
    }
)

credentials = response['Credentials']
# Use credentials['AccessKeyId'], credentials['SecretKey'], credentials['SessionToken']

CLI Reference

User Pool

Command	Description
aws cognito-idp create-user-pool	Create user pool
aws cognito-idp describe-user-pool	Get pool details
aws cognito-idp update-user-pool	Update pool settings
aws cognito-idp delete-user-pool	Delete pool
aws cognito-idp list-user-pools	List pools

Users

Command	Description
aws cognito-idp admin-create-user	Create user (admin)
aws cognito-idp admin-delete-user	Delete user
aws cognito-idp admin-get-user	Get user details
aws cognito-idp list-users	List users
aws cognito-idp admin-set-user-password	Set password
aws cognito-idp admin-disable-user	Disable user

Authentication

Command	Description
aws cognito-idp initiate-auth	Start authentication
aws cognito-idp respond-to-auth-challenge	Respond to MFA
aws cognito-idp admin-initiate-auth	Admin authentication

Best Practices

Security

• Enable MFA for all users (at least optional)
• Use strong password policies
• Enable advanced security features (adaptive auth)
• Verify email/phone before allowing sign-in
• Use short token lifetimes for sensitive apps
• Never expose client secrets in frontend code

User Experience

• Use hosted UI for quick implementation
• Customize UI with CSS
• Implement proper error handling
• Provide clear password requirements

Architecture

• Use identity pools for AWS resource access
• Use access tokens for API Gateway
• Store refresh tokens securely
• Implement token refresh before expiry

Troubleshooting

User Cannot Sign In

Causes:

• User not confirmed
• Password incorrect
• User disabled
• Account locked (too many attempts)

Debug:

aws cognito-idp admin-get-user \
  --user-pool-id us-east-1_abc123 \
  --username [e-mail]

Token Validation Failed

Causes:

• Token expired
• Wrong user pool/client ID
• Token signature invalid

Validate JWT:

import jwt
import requests

# Get JWKS
jwks_url = f'https://cognito-idp.us-east-1.amazonaws.com/us-east-1_abc123/.well-known/jwks.json'
jwks = requests.get(jwks_url).json()

# Decode and verify (use python-jose or similar)
from jose import jwt

claims = jwt.decode(
    token,
    jwks,
    algorithms=['RS256'],
    audience='client-id',
    issuer='https://cognito-idp.us-east-1.amazonaws.com/us-east-1_abc123'
)

Hosted UI Not Working

Check:

• Callback URLs configured correctly
• Domain configured for user pool
• OAuth settings enabled

# Check domain
aws cognito-idp describe-user-pool \
  --user-pool-id us-east-1_abc123 \
  --query 'UserPool.Domain'

Rate Limiting

Symptom: TooManyRequestsException

Solutions:

• Implement exponential backoff
• Request quota increase
• Cache tokens appropriately

References

• Cognito Developer Guide
• Cognito User Pools API
• Cognito Identity API
• Cognito CLI Reference