But the real money is not on the monthly fee you will charge restaurants to update their menus. That you can give for free.
The money is in automating their purchases and delivery of ingredients they need to run their restaurants. If you already know what they serve and have a system running their backend, it's easy to do that.
And everyone in this business knows one of their main pain points is purchasing ingredients: it needs to be done frequently, fast, from a good supplier, preferably close to them, and at a good price. It's a hustle. They spend a lot of money, time and energy doing that.
There are fast-growing SaaS companies in Brazil making a lot of money in that area.