On Monday, Microsoft CEO Satya Nadella appeared at OpenAI’s developer conference and invited developers to build together.

The number one thing we have to do is build the best system, so you can build the best models, and then make those models available to developers,” Nadella told OpenAI CEO Sam Altman.

With its reported $13 billion investment in OpenAI, Microsoft wants to attract more developers to use its Azure cloud infrastructure rather than Amazon Web Services and Google Cloud. In recent years, Azure has become Microsoft’s key growth engine and has helped revive its developer brand.

According to a company spokesperson, around 900 people attended OpenAI’s first in-person event. OpenAI created ChatGPT, an artificial intelligence-powered chatbot that went viral late last year and sparked a rush of investment into the generative AI space. Wall Street Journal reported in September that OpenAI is in talks with investors about a share sale that would value the company between $80 billion and $90 billion

With just a few words of text, Microsoft is able to generate human-like prose using OpenAI’s GPT-4 large language model. The company is introducing GPT-4-based products, including an AI add-on for Office productivity apps and an assistant for Windows 11.

As part of the announcement, OpenAI said people would be able to create custom versions of the ChatGPT chatbot using the GPT-4 Turbo model. In addition, the company said it would reduce the fees that developers pay for its software. Developers can purchase OpenAI’s programming tools directly from the company or through Microsoft. Azure is the host in both cases.

The Azure Marketplace can help developers who are building on OpenAI “get to market rapidly,” Nadella said.