Humanitec provides an API-first platform to build internal developer platforms that enable self-service developer environments. A Postman collection can be used with Humanitec to deploy a full-stack application to Kubernetes, creating resources such as applications, services, databases, and logs through a unified UI and CLI. The process involves fetching the organization name, creating an application, adding backend and frontend services, connecting them, and deploying the complete application. Additionally, a second collection can be used to create a testing environment, deploy changes to it, set up auto-deployment based on branch updates, and optionally deploy to a staging environment. Newman, Postman's CLI tool, can also be used to trigger collections manually or as part of CI processes, allowing for more efficient automation of the deployment process.