Gleb Bahmutov's blog post details the process of using Cypress for end-to-end (E2E) testing in a continuous deployment pipeline, emphasizing its simplicity and effectiveness when combined with immutable deployments via Zeit.co's Now tool. The post showcases the setup and execution of Cypress tests on a local React TodoMVC app, highlighting how these tests can be run locally, on a continuous integration (CI) system, and in a cloud environment to ensure code reliability before making changes to the production system. Bahmutov explains how to integrate Cypress into Git workflows using pre-push hooks and outlines the use of a Cypress Docker image for streamlined testing on CI platforms like GitLabCI. The concept of immutable deployments is explored, where new deployments are tested independently without affecting existing ones, allowing for seamless DNS switching upon successful testing. The combination of Cypress and Zeit.co is presented as a robust solution for maintaining a reliable and efficient deployment pipeline, capable of handling frequent updates while providing peace of mind.