The &quot;minimum&quot; is that you have a (i) name,  (ii) dba filing in that name,  and (iii) a bank account in that name.<p>If you are a sole proprietor you can write off business expenses,  so that is not a reason to form a corporation.<p>Software liability is a funny thing and if deliberate wrongdoing or negligence can be proven and they know your address the corporate veil won&#x27;t stop them from making your life hell.<p>You probably will need some corporate structure once you get around the size where you are hiring managers.<p>There is no substitute to talking to a lawyer about this,  because it is a broad topic with a lot of details.  You don&#x27;t need to incorporate in Colorado,  however,  &quot;jurisdictions of convenience&quot; in places like Delaware and Nevada are more expensive.<p>As for S vs C that is a matter how you file your taxes,  not how you register your company (Delaware doesn&#x27;t know if you are an S or C and doesn&#x27;t care.)