When you're talking about some work as discrete as "write (or clone) an API Client library in [the contractor's language of choice]" Most of the advice here is

When you're talking about some work as discrete as "write (or clone) an API Client library in [the contractor's language of choice]" Most of the advice here is overblown. It's a small amount of work, you probably already have acceptance tests for your other libraries (which can be copied verbatim), and documentation is minimal. Just get a recommendation from somebody else who knows the language you're looking for well and pay whatever they ask, presuming that what they deliver passes whatever tests you already have. Make sure that the contract says that you own the copyright when you pay/they deliver. the fact that it will be OSS doesn't really matter much either way. If you're worried, agree on a deadline before you sign a contract and put in a positive or negative incentive around that. I've been a consultant for several years. The ones you want aren't spending their time on oDesk and elance, and they're not cheap. I've tried to be that guy, you can't compete. I've tried to hire that person, and you can't get repeatable results. You guys are hackers, you have a strong network. somebody somewhere knows someone with C# experience who has read a decent blog post on REST.