TikTok is the international twin of China’s mobile short video app, Douyin, and one of the fastest growing short video platforms in the world. Owned by Chinese tech giant, ByteDance, TikTok and Douyin share many similarities in terms of appearance, functionality, and platform affordances; however, they exist in radically different markets and are governed by radically different forces. Unlike other popular mobile media platforms in China and internationally, TikTok and Douyin are neither part of the big three tech giants in China nor the big five in the US. This provides an interesting case study to investigate how an emerging internet company adapts its products to better fit divergent expectations, cultures, and policy frameworks in China and abroad. Using the app walkthrough method informed by platformization of culture production theory, this study highlights the similarities and distinctions between these two platforms. We argue the co-evolution of Douyin and TikTok is a new paradigm of global platform expansion that differs from strategies of regionalization adopted by previous major social media platforms. We contribute to platformization theory by developing the concept of parallel platformization to explain ByteDance’s strategies for surviving in two opposing platform ecosystems in China and abroad.