Steam
Playtests and beta branches for games before release.
Early access on Steam is tricky: Playtest hands out free keys via a button, beta branches open with a password, demos live separately. Indies polish balance and hunt bugs for months before release.
A Steam campaign gathers playtesters with commitments: not “grab a key and vanish”, but report back — bugs, impressions, screenshots.
[✓]playtest keys and beta branches
[✓]Windows, macOS and Linux
[✓]feedback before Early Access
[✓]testers with obligations, not a crowd