Twitch further solidified its lead in the game streaming market in the first quarter of the year, with gains in both average concurrent viewership and peak concurrent viewership, while the number two streaming site, YouTube Gaming, saw losses on both fronts. According to a new report from Streamlabs, which has visibility into the market thanks to its software platform used by hundreds of thousands of streamers, Twitch viewership was up by 21 percent in the quarter, growing from 788K average concurrent viewers in Q4 2017 to 953K in Q1.

Meanwhile, YouTube Gaming dropped 12 percent from 308K average concurrent viewers to 272K during that same time.

Other streaming services also saw gains, but their viewership numbers are much smaller.

Facebook, for example, grew viewership by 103 percent to reach 56K average concurrent viewers, Periscope grew 18 percent to 94K, and Microsoft’s Mixer grew 90 percent to 9.5K. (Microsoft’s real figures are likely much higher, however, because Streamlabs can’t track Mixer’s viewership on Xbox – which is most of it. Streamlabs is also missing some of Facebook Live’s viewership, as it can’t track private live streams only shared with friends.)

It’s no surprise that Twitch has a killer quarter, however.

The company announced in February it saw a record-breaking 388,000 concurrent viewers tune into a stream by Dr. Disrespect. This milestone was then blown out of the water the following month when Ninja played Fortnite with Drake and Travis Scott, reaching 628,000 concurrent viewers.

But even without these special events, Twitch has been growing.

It also saw a 33 percent increase in average concurrent streamers in Q1, going from 27K to 36K. Mixer and Periscope gained as well, up 282 percent and 126 percent, respectively. But YouTube Gaming dropped by 13 percent on this metric, going from 8.7K average concurrent streamers in Q4 2017 to 6.1K in Q1.

As Twitch grew, streamers made more money, too, Streamlabs found.

It claims to have seen the biggest quarter ever in Streamlabs tipping volume, rising 33 percent to $34.7 million, up from $26.2 million in the prior quarter. (Keep in mind this is tipping that takes place through Streamlabs software – the total tipping volume across platforms will be even higher.)

The company chalks up these gains to a variety of factors, including streamers’ more professional-quality videos, streams from games with huge audiences like Fortnite, growth of non-game streams, and more.

Streamlabs’ full report, here, also delves into its own gains in terms of traction, as well as the breakdown of the quarter’s most popular games.