AWS Cognito user pool identity REST examples

We are looking into using user pools for our application. I would like to try out API in REST manner. Documentation at https://docs.aws.amazon.com/cognito-user-identity-pools/latest/APIReference/Welcome.html doesn't have request and response examples like others. Looking for SignUp, ResendConfirmationCode,ChangePassword and ConfirmSignUp examples.

Currently it is not in Cognito user pools documentation, but following example should work for SignUp. Similarly you can formulate it for other APIs. Payload should be what has been mentioned in the documentation you pointed

CONTENT-TYPE: application/x-amz-json-1.1
X-AMZ-TARGET: com.amazonaws.cognito.identity.idp.model.AWSCognitoIdentityProviderService.SignUp

HOST: https://cognito-idp.us-east-1.amazonaws.com

{
"ClientId": "string",
"Password": "string",
"SecretHash": "string",
"UserAttributes": [
    {
        "Name": "string",
        "Value": "string"
    }
],
"Username": "string",
"ValidationData": [
    {
        "Name": "string",
        "Value": "string"
    }
]
}

Due to complex SRP calculation logic on client side during authentication, it is recommended to use the SDKs provided along with Cognito user pools. But seems like the APIs you mentioned above should not have this calculation, so it should be possible to make REST calls.