Most online casino sites these days have games from a wide range of studios. Developers compete with each other for the most exciting games to play, giving more choice to users.
But which companies are some of the most popular casino games studios right now?
Approaching the 15-year anniversary of the company's foundation, Evolution Gaming is certainly one of the top games studios in operation today.
Live dealer casino games are the speciality of Evolution Gaming, which runs everything from casino classics such as blackjack and roulette through to games like Deal or No Deal.
More than 300 casino operators have signed up Evolution Gaming to provide games on their sites, while the company has scooped a large number of industry awards as well.
Evolution was able to celebrate being named the Online Casino Supplier of the Year at the Global Gaming Awards. The company has also been given the Casino Content Supplier of the Year prize at the EGR Nordics Awards.
Arguably the biggest casino games studio in operation is NetEnt, short for Net Entertainment. NetEnt is considered by many to be the best casino games developer with more than 200 different titles having been released by the company so far.
Starburst and Gonzo's Quest are two of the most popular online casino games to have come out of the studio, which is also the company behind Dead or Alive 2 and Guns N' Roses.
Like Evolution, NetEnt has been awarded at several industry ceremonies over the years, including the EGR Awards, Global Gaming Awards and International Gaming Awards.
Next up is Play'n GO, certainly one of the leading casino games studios in the industry. New games are being released by the company on a regular basis, with Cat Wilde and the Doom of Dead one of the latest titles to come from the developers at Play'n GO.
The game is a follow-up to Rich Wilde and the Shield of Athena, where the character of Cat made her debut. Rich Wilde is one of the most famous characters to have been created in the world of online slots, so Play'n GO will be hoping that its latest release is another smash hit.
There is no doubt that Microgaming has to be included in any list of the world's most popular casino games studios.
The company is behind a lot of slots based on TV series or films, such as The Dark Knight Rises, Jurassic World and Game of Thrones. Recent releases from Microgaming also include 11 Champions, Wild Catch and Aliya's Wishes.
Avalon, Thunderstruck and Dragonz are among the most successful Microgaming releases to date and more than 800 titles have been released by the studio. It is clear the company is extremely prolific, having come up with its first online casino software all the way back in 1994.
Additionally, Microgaming has built a progressive jackpot network that the company claims is the largest in the world. Over €1 billion has been paid out through the network already.
Even though the company was only founded a few years ago, Yggdrasil Gaming is already a leading developer in the industry. The young age of Yggdrasil Gaming means its library of online casino games studios is not vast, but the firm goes for quality over quantity.
Innovation awards have been flowing towards Yggdrasil Gaming in recent times, showing the high level of praise for the company from within the sector.
Holmes and the Stolen Stones is one of the top online slots to have been released by the studio so far, while Blood Moon Wilds is another Yggdrasil Gaming title that is well worth checking out.
Wrapping up our list of some of the world's most popular casino games studios is Quickspin, which like Yggdrasil Gaming is a relatively new name in the industry.
Set up in Stockholm around a decade ago, after a buyout Quickspin is now a part of Playtech, which is one of the largest online gaming software suppliers on the planet.
Quickspin aims to release one new online slot game each month, meaning there is always something fresh for casino customers to try out from the developer.
Wild Tome of the Wood is one of the top Quickspin games to have come out so far.