How to set a Slack Reminder with Slack Reminder API to a channel?

The current Slack API for Reminders allows developers to create a reminder for a specific person. This reminder is directly messaged to them via Slackbot; however, I want the reminder to be posted in a public channel. The Reminder API does not specify a channel argument so I’m unsure how to accomplish this with their API. I’ve posted my current code to create a reminder for a specific user below as reference.

Slack Reminder to user

var payload = {
    "token": settings.slackToken,
    "text": text,
    "time": time,
    "user": user
};

var options = {
    'method': 'post',
    'payload': payload
};

var response = UrlFetchApp.fetch(settings.slackRemindersURL, options);

Answer

I had this same question about a month ago. When I asked slack support, this was their answer:

It’s not currently possible to use the API to set a channel reminder. However, it’s an interesting idea and one we’ve had from other developers too. I’ve shared your thoughts with the Platform team for consideration in a future release.

Sorry for being the bearer of bad news. But maybe if you email them as well, they will know it is a needed feature.