[mchakravarti7]

You can use OPT, but would suggest not to so so because it will have implications on how long you can stay in the US after graduating. CPT is another option if your college allows you to use it. Post-graduation, OPT, H1-B, B1/B2 and O1 are all viable options of varying difficulty

[geekytech03]

For H1B I should be employed by someone. In OPT, I couldn't find anything related to self-employment(https://www.uscis.gov/working-united-states/students-and-exc...).

[mchakravarti7]

There are VC firms that can help you work on an H1B, or even make you an employee in the short term. There's also programs in MA where an university can employ you on an H1B and let you work on your startup. I believe UMass Boston's VDC program is one. OPT is a completely valid option too (source: know a ton of people who have used this and have extensively spoken to attorneys about it)