[safek]

This strikes me as a case where you vaguely perceived a problem, thought "hmm, personal problems are the best source of project ideas," and quickly rushed to create a solution because you're a maker who enjoys making things. Did you open a text editor alongside Slack, or message yourself/slackbot, and find both solutions wanting? Would you pay $1/user/month for the added benefit of your solution?

My rude, unsolicited, very possibly erroneous, but ultimately well-intentioned suggestion is that you release it as a free service and maybe open source it. If you brand it well you can collect some stars. But I can't see someone paying for this.

[stevesun21]

what I can say, this is a problem I faced every day, especially, I need to add some code in my message or I write a long updates to my team.

I don't see any reason why I make it for free or even open source. I charge my customers monthly fee is not just based on how much time I spend to build, it's about how much commitment I have to keep it working to provide my customers high quality service.

If you think give tips to a waiter/waitress after they serve you meals and drinks makes sense, and then, why I provide my service for free? My pricing mode maybe need to judge a little in the future, but free is never my option.

[safek]

My guess about the project's origins may have been wrong. If so I apologize.

I'm not saying you don't deserve pay for your work, or that it's somehow wrong of you to charge money. I'm worried you'll have trouble finding paying customers because you're competing with a feature that Slack already comes with (slackbot).

I want this to work for you! If you find a way to sell this, I'll be pleasantly impressed and delighted to admit I was wrong.