WWE SummerSlam 2020 was available to watch live on the WWE Network and select pay-per-view providers. The kickoff was also streamed on WWE's social media platforms like YouTube, Twitter, and Facebook, and the main event was broadcasted on the WWE Network and certain cable/satellite providers. The WWE Network supports multiple devices including Apple TV, Amazon Fire TV, PlayStation 4, Roku, Xbox One, Android and iOS devices with the WWE app, and many smart TVs.
For current or recent years, such as SummerSlam 2025, it is streamed live on Peacock in the US and Netflix in many international markets. Some theaters in the US also offer live screenings of the event.
To watch SummerSlam 2020 specifically now, one could look for on-demand options on streaming platforms like Prime Video or WWE Network's archives if available.
So for SummerSlam 2020, watching on WWE Network or platforms offering WWE events like Prime Video would be the main options. For recent editions, Peacock and Netflix are the primary streaming services depending on your location.