AWS IAM policy additional to AWSLambdaFullAccess and AmazonAPIGatewayAdministrator policies.

OwnServerlessPolicy

{
    "Statement": [
        {
            "Action": [
                "apigateway:*",
                "cloudformation:CancelUpdateStack",
                "cloudformation:ContinueUpdateRollback",
                "cloudformation:CreateChangeSet",
                "cloudformation:CreateStack",
                "cloudformation:CreateUploadBucket",
                "cloudformation:DeleteStack",
                "cloudformation:Describe*",
                "cloudformation:EstimateTemplateCost",
                "cloudformation:ExecuteChangeSet",
                "cloudformation:Get*",
                "cloudformation:List*",
                "cloudformation:UpdateStack",
                "cloudformation:UpdateTerminationProtection",
                "cloudformation:ValidateTemplate",
                "iam:AttachRolePolicy",
                "iam:CreateRole",
                "iam:DeleteRole",
                "iam:DeleteRolePolicy",
                "iam:DetachRolePolicy",
                "iam:GetRole",
                "iam:PassRole",
                "iam:PutRolePolicy"
            ],
            "Effect": "Allow",
            "Resource": "*"
        }
    ],
    "Version": "2012-10-17"
}