Customer development is a four-step framework that guides product managers through the process of discovering and validating customer needs and building products that effectively meet those needs. The process involves customer discovery, validation, creation, and building company processes around the customer's needs.
Slack's development team initially built the platform for internal use. However, through customer development processes, they discovered a broader market need for efficient team communication. This led to Slack pivoting towards a public offering, focusing on solving communication challenges for teams worldwide.