At long last Blizzard has released detailed information on the Overwatch beta. Starting October 27 the beta consists of two parts: an closed part with a limited amount of testers where the objective is to gather feedback on the gameplay (including "balance, feel and fun").
More participants will be invited in to stress test the infrastructure and servers. The first of these beta test weekends will be held after BlizzCon (November 6-7).
Blizzard mentioned that the closed beta will begin its roll out in North America, followed by Europe and Asia in that order. Exactly when the beta test will open up in Europe is still unknown, but hopefully it won't be too long after the Americans. The beta is only available for Windows and requires a Battle.net account.
First is the closed beta, and it runs initially in North America, followed by Europe and Asia, in that order. The Overwatch-beta is Windows only and will require Battrle.net.
If you want to learn more about Overwatch we suggest you check out our interview with game director Jeff Kaplan and senior game designer Michael Chu.