Mock Dream is a free Chrome extension designed for developers to efficiently mock HTTP requests. It allows users to intercept fetch and XMLHttpRequest calls and replace them with custom responses based on defined rules. This tool is particularly useful for building user interfaces without needing the backend ready, as well as for reproducing edge cases such as server errors or slow responses. Furthermore, it enables offline demonstrations of various flows, making it a versatile addition to any developer's toolkit.

Key features include an intuitive live traffic log that displays all requests, the ability to create rules with a single click, and options for importing and exporting rule sets in JSON format. Mock Dream operates entirely locally, ensuring user privacy with no data collection or transmission. The extension supports a detached window mode for better usability and includes a master switch for easy activation and deactivation of rules.