Toast displays the feedback and confirmation messages after the user takes any action.

This event “$A.get(“e.force:showToast”)” handled by the one.app container. It’s supported in Lightning Experience, Salesforce Mobile and Lightning Community.

showConfirmationToast : function(component, event, helper) {
    var toastEvent = $A.get("e.force:showToast");
    toastEvent.setParams({
        "title": "Success!",
        "message": "The record has been created successfully."
    });
    toastEvent.fire();
}

There are many attributes available to control the behavior and look and feel of this toast message.

NAME	TYPE	DESCRIPTION
title	string	Specifies the title for a message to display. The title is shown above the message in a slightly larger font.
duration	integer	Length of time the toast is visible for, in milliseconds. Applies to ‘dismissible’ or ‘pester’ toast modes. The default is 5000ms if the provided value is less than 5000ms.
message	string	The message to display in the toast.
key	string	Icon to use when toast type is ‘other’. Icon keys are available at the Lightning Design System Icons page.
mode	string	The toast mode, which controls how users can dismiss the toast. Valid values are ‘pester’ and ‘sticky’. The default is ‘dismissible’, which displays the close button.
type	string	The toast type, which can be ‘error’, ‘warning’, ‘success’, or ‘info’. The default is ‘other’, which is styled like an ‘info’ toast and doesn’t display an icon, unless specified by the key attribute.
messageTemplate	string	Overwrites message string with the specified message. Requires messageTemplateData.
messageTemplateData	object[]	An array of text and actions to be used in messageTemplate.

The below example will display the toast message for 5000ms and it will auto dismiss after that.

showConfirmationToast : function(component, event, helper) {
    var toastEvent = $A.get("e.force:showToast");
    toastEvent.setParams({
        "title": "Success!",
        "type" : 'success',
        "mode" : 'dismissible',
        "duration" : 5000,
        "message": "The record has been created successfully."
    });
    toastEvent.fire();
}