The most concurrent viewers for a Twitch stream is 2,468,668, and was achieved by David "TheGrefg" Cánovas Martínez (Spain)
TheGrefg shatters Twitch record with more than 2 million viewers
Most Viewed Twitch Clips 2020, neekolul chess
Twitch's Viewership Record Shattered By The Grefg - GameSpot
Twitch in Spain: Spain's 'TheGrefg' shatters world record for
IGN - Content creator TheGrefg streamed his Fortnite reveal to over 2.4 million people live on Twitch, breaking any previously held record by any streamer ever.
New Viewer World Record on Twitch with over 2.5 Million
TheGrefg Breaks Ninja's Record for Most Viewed Twitch Stream - Sudairy
Fortnite Big Bang Shatters Streaming Records - Stream Hatchet
News You Might've Missed on 1/11/21: TheGrefg Smashes Twitch
Fortnite Streamer Breaks Twitch's All-Time Concurrent Viewer Record