Backstory: My accountant retired this year and I had to scramble to find someone new. I had a few 1099's to send out and I was a bit behind. I tried to find a simple service to help pre-populate a 1099 form and couldn't find a small, simple service.
The Idea: A website to help fill out 1099 forms.
Deep Dive: You would build a series of questions to ask your customers to complete a 1099 form. You could eventually branch out to different tax services but keeping it simple and only offering payment per item will keep customer satisfaction high.
Validation: I looked for one and ended up signing up for a recurring system to send a once a year form? Kind of mind blowing.
Monetization: You would charge a set fee for each for generated. It scales when someone is sending multiple forms and you can give a discount at scale.