There are so many freelance job sites out there now that finding a gig shouldn't be like looking for a needle in a haystack. Getty Images

As 2015 comes to a close, it's been hard not to notice how an increasing number of friends and colleagues are moving towards the freelancing model. People are simply more comfortable being their own boss these days, even if it means a bit more uncertainty than they might have at a full-time position. As of October 2015, 54 million people in the US alone have done freelance work in the past year. That's roughly 34 percent of the entire US workforce.

With so many freelancers doing work in the US and around the world, a freelance marketplace has evolved. Employers are the demand, freelancers the supply. Several job sites have risen to connect the buyers and sellers in this market for a profit by providing a streamlined platform that removes many of the complications of freelancing. If you're going to make the transition to freelancing in 2016, you'll need to know some of the biggest players in the market. Here are ten of them.

1. Toptal

This is one of the most well-known and widely-used sites out there right now. Toptal connects clients with a network of freelance developers and designers from more than 90 countries around the world. The service only works on technical projects, but Toptal does those well. The company rigorously screens its freelancers for personality, English-speaking, technical knowledge and skill. Ultimately, only 3 percent of applicants are accepted into Toptal's network. This service offers account teams to help clients find the best match. Interestingly, they are also an entirely remote company and don't have an office anywhere in the world. Go figure.

2. Upwork

Upwork is the giant of the freelance industry and is the largest network by a long stretch. Formed out of the merger of two large freelance job sites, oDesk and Elance, Upwork currently has 9 million freelances in its network and 1.5 million clients. The service covers a wide range of freelance jobs that can be done remotely, including everything from virtual assistants to paralegal work. Upwork offers hourly and fixed price projects, but they provide no vetting or screening for clients. Instead, they leave the interview process and technical assessment to the clients, who can then bid on the freelancers they want to hire.

3. 99Designs

I've had friends who've been using this one for years here in the Bay Area, it's based in Oakland, and Tim Ferris mentions them all the time on his podcast, so I can't escape this company. 99Designs is exclusively for designers, but it puts a cool spin on the freelance platform. Rather than let clients scroll through freelance profiles, clients crowdsource their projects. Clients first fill out a brief detailing their project, and then designers can submit work based on that brief. Clients pick the best submission, and the winning designer gets the money. If they so choose, clients can then continue to work with that designer to design a fully-fledged version of what they did for the contest.

99Designs has over a million designers in its network and has completed over $100 million in transactions between clients and designers, so the unusual business model is clearly working well for the company.

4. FlexJobs

FlexJobs stands out as a freelance job site by vetting jobs, not freelancers. Instead, freelancers are the ones who pay for the platform. In return, FlexJobs provides a list of jobs, currently just under 30,000 in number, that the platform has vetted as legitimate. Freelancers can then apply to those jobs through the contact information provided by FlexJobs. The service also provides skill testing, job search tips, and special members-only discounts through site partners to create loyalty among its freelance network and provide them added benefits.

5. Guru

Since its inception in 2001, Guru has completed 1 million jobs and received $200 million in payout. Today, Guru has 1.5 million freelancers on its platform. In order to look through such a large number of freelancers effectively, clients can look through freelancer portfolios that include previous earnings and client reviews as well as skills and experience. Freelancers in turn can get an idea of whether a client's job is viable by looking at how much they have spent on freelancers in the past.

6. Crowded

A self-described "marketplace for on-demand workers," Crowded aims to fix the supply and demand problem with freelance job opportunities: how do freelancers find job opportunities, and where do companies hire effective freelancers? Crowded pulls freelance job postings from several on-demand platforms and makes them available to its network of freelancers. The company was just founded in 2015, and even with its soft launch, the platform already has over 11,000 freelancers and 400 platform partners. Don't be surprised if this freelance site becomes much bigger in 2016, just based on the growth we've seen so far.

7. Freelancer

Freelancer boasts 17 million registered users, but not all of them are active. Regardless, what separates it from other job sites is its competitive edge. Freelancer regularly hosts contests in which employers post a project with a money prize, and freelancers bid on the project with their submissions. This serves as a way for freelancers to showcase their talent and hone their skills and makes the hiring process easier for employers as they can see different takes on their project. It should be noted that this process may not be very conducive to people just trying out freelancing or who are unsure of their skills.

8. PeoplePerHour

PeoplePerHour is a freelance site for all skills related to web projects, including web developers, designers, and SEO experts and marketers. Aiming to be a one-stop shop, PeoplePerHour wants to make your web building experience as streamlined as possible through their platform. To simplify the process even more, PeoplePerHour offers a tool called WorkStream, in which management, payment, and communication between employers and freelancers is all handled in one location.

9. Simply Hired

Simply Hired has a wider range than most freelance job sites because this particular website isn't focused on freelance work only. It's a job directory, offering 6 million jobs in 974 occupations through 700 thousand unique employers in 24 different countries. The site has a large following, supporting 30 million unique monthly visitors and in a year those visitors make roughly one billion searches. While not exclusively for freelance work, Simply Hired is simply too big to be ignored by this list.

10. Behance

Behance isn't normally thought of as a hiring platform, as it is also a showcase platform for designers, but it is quite an effective site for hiring those designers. Not only can clients look through designers' portfolios and see examples of their work, but clients can see how other people have reacted to that work as well. Clients pay a fee to post jobs on the site, but in return they get custom hiring recommendations for their project as well as access to Behance's network of 5 million creatives. This is a very active network that isn't leaving the freelance market any time soon.