  Crowdsourcing of jobs to online freelance markets is rapidly gaining
popularity. Most crowdsourcing platforms are uncontrolled and offer freedom to
customers and freelancers to choose each other. This works well for unskilled
jobs (e.g., image classification) with no specific quality requirement since
freelancers are functionally identical. For skilled jobs (e.g., software
development) with specific quality requirements, however, this does not ensure
that the maximum number of job requests is satisfied. In this work we determine
the capacity of freelance markets, in terms of maximum satisfied job requests,
and propose centralized schemes that achieve capacity. To ensure decentralized
operation and freedom of choice for customers and freelancers, we propose
simple schemes compatible with the operation of current crowdsourcing platforms
that approximately achieve capacity. Further, for settings where the number of
job requests exceeds capacity, we propose a scheme that is agnostic of that
information, but is optimal and fair in declining jobs without wait.
