Why Google's new Interactions API is such a big deal for AI developers

For the last two years, the fundamental unit of generative AI development has been the "completion." You send a text prompt to a model, it sends text back, and the transaction ends. If you want to continue the conversation, you have to send the entire history back to the model again. This "stateless" architecture—embodied by Google's legacy generateContent endpoint—was perfect for simple chatbots. But as developers move toward autonomous agents that use tools, maintain complex states, and "think" over long horizons, that stateless model has become a distinct bottleneck.Last week, Google DeepMind finally addressed this infrastructure gap with the public beta launch of the Interactions API (/interactions).While OpenAI began this shift back in March 2025 with its Responses API, Google’s entry