How to fix Error: Error creating Cognito User Pool: LimitExceededException in Terraform

Log into your AWS Console and navigate to Amazon Cognito. Count existing user pools in the affected region, or use the AWS CLI:

aws cognito-idp list-user-pools --max-results 60 --region us-east-1

This lists all user pools in the specified region. Remember that Cognito quotas are per-region per-account, so a pool in us-east-1 doesn't count toward quotas in us-west-2.

Check if Terraform is trying to create a duplicate user pool:

terraform state list | grep aws_cognito_user_pool

If the pool already exists in state but you're getting an error, refresh your state:

terraform refresh

If the pool exists in AWS but not in your Terraform state, import it:

terraform import aws_cognito_user_pool.example <user-pool-id>

Get the user pool ID from the AWS Cognito Console.

If you have reached the 1,000 user pool limit, check if you can consolidate:

# List all user pools with basic info
aws cognito-idp list-user-pools --max-results 60 --region us-east-1 --query 'UserPools[*].[Id,Name,CreationDate]' --output table

Review which pools are:
- Development or testing pools no longer in use
- Duplicate pools created by accident or automation
- Pools serving the same purpose

Delete unused pools via the AWS Console or CLI:

aws cognito-idp delete-user-pool --user-pool-id <pool-id> --region us-east-1

Deleting a pool frees up the quota immediately.

If you legitimately need more user pools, request a quota increase:

1. Go to AWS Service Quotas console: https://console.aws.amazon.com/servicequotas
2. Search for "Cognito"
3. Find "User pools per region" or "User pools"
4. Click on the quota and select "Request quota increase"
5. Enter your desired value (AWS typically allows increases up to 10,000+ pools)
6. Submit the request

AWS usually approves quota increase requests within minutes to a few hours. You'll receive an email confirmation. Note that quota increases are per-region, so you may need separate requests for each region you use.

If the error is related to API request rate limits rather than pool count, optimize your deployment:

# Check if you're hitting rate limits (look for TooManyRequestException in CloudWatch)
aws logs filter-log-events --log-group-name /aws/cognito/<pool-name> --filter-pattern TooManyRequestException --region us-east-1

In your Terraform configuration, implement retry logic or stagger resource creation:

resource "aws_cognito_user_pool" "example" {
  name = "my-pool"
  # ... other config

  timeouts {
    create = "10m"
    update = "10m"
    delete = "10m"
  }
}

In your application, implement exponential backoff for API calls and cache authentication tokens to reduce request volume.

Once your quota increase is approved, retry your Terraform deployment:

terraform plan
terraform apply

If using CI/CD pipelines, ensure:
- Your AWS credentials have permissions to create Cognito user pools
- Your pipeline has the latest credentials with updated quotas
- Multiple parallel deployments are not creating duplicate pools

Consider adding a delay between resource creation in large deployments to avoid rate limit issues:

terraform apply -parallelism=1