Do I own the IP created by a contractor?

As an initial matter, at least part of your venture's budget should account for legal services. Generalized opinions on websites like IPNexus and Avvo are helpful, but truly useable advice is very fact specific and should be elicited through private correspondence with an attorney.

That being said, the other contributors raise important points: (i) you very likely will not own the work created by the third-party ICs; and (ii) you need some contractual language in place. "Work for hire" is, like many IP-related terms, a bit abused and misunderstood. A "work made for hire" is defined in 17 U.S.C. s 101 and most often the definition will not apply to what one might hire an IC to do. Language invoking the term is invariably incorporated into an IC agreement's IP provision(s), but more important than calling something a "work for hire" (when it usually is not) is to have catch-all language contractually assigning all IP rights in whatever is being created to you, the client.

Software development-related IC agreement do not have to be monstrous and with some judicious searching, you should be able to find a local IP attorney who can evaluate your situation and provide a flat-fee quote.

Disclaimer:

This communication: (i) is not a substitute for professional legal advice; (ii) does not create any attorney-client relationship; and (iii) is not a solicitation to offer legal advice. There is no duty to keep any confidential information you disclose in this forum confidential or refrain from providing representation adverse to your interests. You should seek the advice of a licensed attorney in an appropriate jurisdiction before taking any action that may affect your rights.